Red Lines, Part 4

By Chris McCarthy


Leo drives the van out of the small parking lot and from this vantage point sees why Jack and his team chose it. It’s well hidden and poorly lit. You could look from the main road and see the hill up to the freeway and think it was a dead end, without seeing the driveway into the small parking lot just before the hill. 

Leo edges out past a stop sign on Main Street and takes a left, following the GPS, on his way to the freeway to head north back to Los Angeles. He wonders why Jack was in Manhattan Beach earlier today. Was he following the man that Leo had killed? What was this larger plan Jack had referenced? And who was the man in the van who ran into another vehicle at the top of the hill? Jack had been sparing in details, but was clear that the only way for Leo to get his life back is to trust Jack and his associates. But still the thought lingered… Should he have run? But then what would happen to his passengers?

Leo notices he’s gripping the wheel tightly and catching his reflection in the mirror, he looks like he’s aged five years in half a day.

Leo looks past his face in the rearview and catches the eye of the girl who looks a year or two older, the mother hen. 

“Where are you from?” He asks.  

She nods at the road ahead. “LA.” She says then drops her eyes. Leo nods. “Are you taking us home?” She asks, looking up again. 

Leo says “I don’t know exactly.” Forcing certainty, he adds, “But I know you’ll be safe there. I’m Leo by the way. What’s your name?”

“Emily.” 

The girl in the seat next to her has brown hair cut into a short bob and large brown eyes. She looks to be about thirteen. 

“How do we know you’re not taking us to Mexico.” The girls with the large brown eyes says. 

Emily, who has decided to trust Leo, turns to the girl and says, “We’re going the opposite direction,” Then she calmly looks out the window. 

Leo drives on the 405 freeway.  A radio buzzes then a channel opens, scratchy and loud, startling Leo. “Get off the freeway.” Leo pulls the black receiver off its hook on the dashboard. He looks at it for a moment then pushes a red button on the side. 

“What? Who is this?” Leo asks. 

“I want you to get off at the next exit. There’s an accident near Hawthorne. I need you to get off the freeway.” The voice says. 

Leo feels goosebumps raise on his arms, again feeling the seriousness of his situation. He looks in the rearview for anything suspicious. Nothing catches his eye. 

A crackle from the radio. Leo pushes the speech button and says, “I’m here. I’m here.”

“I said get off at Artesia.” 

“I’m getting over. I’ll get off right now. Then what do I do?” Leo asks. 

Leo looks behind him and sees a car with a busted headlight. It doesn’t follow him into the far right lane so he relaxes then sees the girl with the brown eyes staring at him in the mirror. She looks scared now for some reason maybe thinking their destination is nearby. He still doesn’t understand how these girls had gotten here. Maybe he’d learn soon. Or if he was lucky maybe he’d be able to leave all of this behind after he finishes this drive. He’d had two chances to get out of this but took neither, not that they were decent options. Once at the house in Santa Ana. And another chance when he could have booked it and gotten lost in the shadows of the back alleys and closed mechanic shops instead of getting into the driver’s seat of this van. 

Self-sabotage is in his DNA he remembers Celia saying. 

“Are you there? I said what do I do then?” Leo says into the radio.  

“I’m here, sorry I was checking with our other car to see if our path is clear. Just focus on driving. This will all be over soon.” 

“Ok…”

“Take a right on Aviation in just over a mile and keep going until I tell you different.”

“Can you at least tell me where we’re going?”

“Just be patient Leo. And don’t speed.” 

“Yeah, I got it. Don’t speed.” Leo says, shaking his head.

Leo turns right on Aviation Blvd, a seven mile thoroughfare stretching north to south from the city Westchester to the South Bay Area of Los Angeles, which includes Hermosa and Redondo beach.

After following a few more directions from the man on the radio, Leo turns left on Manchester street right after the airport. He drives through the middle class neighborhood and, following the man’s instructions, pulls into a small parking lot between a cul-de-sac of small one-story homes and before a large warehouse. There are about five small storage units with sliding steel doors. He pulls in and one of the storage unit doors opens and a man holding a walkie-talkie ducks his head under the opening sliding door and walks out. He waves Leo inside, his eyes scanning everywhere but the van. 

One of the girls in the back seat sniffles and the mother hen comforts her. The brown eyed girl has her head raised looking out the windows trying to gather any information she can about their location. She’s not getting much. Leo hears murmurs from the other four girls further back in the van.  

“It’s ok.” Leo says. “I think you’re safe now.” 

“But you don’t know,” Emily, the mother hen, says as she reaches over and combs her fingers through the brown-eyed girl’s hair.

The headlights blast against the back wall of the small twenty square foot storage unit, which is empty except for random scraps of things presumably stored by people over the years. A piece of coiled rope. A few cardboard boxes broken down and set against the right side of the unit. An old tire with a gash in it leaning against the wall. A single light bulb hangs down from the center of the ceiling. Leo pulls to a stop three feet in front of the back wall, the light bulb just grazing the top of the van, causing light to bounce around the unit. 

The man with the radio walks up along the driver’s side of the van and taps the door. Leo searches his face for what he’s trying to get across but the man is looking at the back wall. Leo follows his eyes and watches as the concrete wall slides open with the ease of a metal gate on wheels fencing off a driveway. Only he sees no wheels or other apparatus. The illusion is seamless. It just looks like a concrete slab sliding over to expose an opening in the wall.

The man taps the door again and this time looks at Leo and points at the window. It takes Leo a moment to find the window button to roll it down. 

“Drive,” the man says. 

Leo recognizes the voice as the one he heard over the radio. The man waves him forward and Leo pulls the steering wheel lever down a notch, putting the car back in drive. He drives down a small ramp then at the bottom turns left into a large well-lit…facility would be the best way to describe it. 

Two men walk out from either side. One of them carries a pistol in his hand, held low at his side, presumably to not spook anyone. The other holds a hand up, indicating he wants Leo to stop. Leo stops the car, the only sound in the car his breathing and assorted sniffles and movements from the girls behind him. The low hum of the motor has an eerily reassuring quality to it. 

The unarmed man walks to the side of the van and opens the sliding door. Leo looks over his shoulder and sees that two women have appeared from somewhere behind the van. They talk to the girls in hushed, reassuring tones.  

The armed man’s eyes are alert, searching every inch of the van. Leo hears a slight thud and realizes the wall up the ramp has closed. The man with the radio jogs down it and joins the women at the open van door. 

He looks in, scanning each the girl’s faces as the women help them out. One of the women moves her eyes over the faces and bodies of the girls with the searching eyes of a physician then leads the girls over to one corner of the room where there are some chairs, iPads, blankets, cots and a tent. The man with the radio looks at the woman. She nods her head. 

He turns away from the van and speaks into his radio with an air of military efficiency. “She’s here. We have her.” 

The armed man nods to Leo to get out of the car just as the man with the radio walks around to the driver’s side and opens Leo’s door. 

“So who the fuck are you?” He asks. Leo looks around the large sterile room, which resembles an empty floor of a parking structure, and sees three more capable-looking men, most likely armed discreetly. 

A man dressed in business casual attire walks up at a fast clip, looking down at a phone laying flat in his palm. He gets to the two men and holds it out. 

The man with the radio puts his radio on his belt, an annoyed look on his face. 

“It’s for you.” He says. After another second, he takes the phone out of the other man’s hand and holds it out for Leo to see. Leo looks at the phone. It’s a video call. 

“Leo? Are you Leo?” The man in the video says. 

“Yes. I’m Leo.”

“Thank you for your help.” The man says, sincerely. Behind him Leo notices a painting on the wall and a bureau. Leo can just see the tops of photo frames and imagines the man sitting in the dining room of an expensive home. 

“You’re welcome. Who are you?”

“Just a guy trying to help. Like you. I just wanted to say thank you. We don’t have a lot of time. Mike will tell you next steps. I have to go. Thank you, Leo.”  

Leo looks over and sees the two women are helping the girls, now clad in clean sweatshirts and blankets, get into two small odd-looking cars. It takes him a second to realize they’re the carts baggage handlers drive on the tarmac as they load and unload bags into planes. 

Leo feels a deep chill in the air. 

“Are we…under the airport?” Leo asks. 

Mike takes back his phone and nods. “We’ll have time to talk on the flight.” 

Mike takes in the look on Leo’s face and says, “There’s nowhere else for you to go. You need to stay with us for your own safety.” 

“What do you mean? Can’t I go back home now? I thought everything was…cleaned. Like the scene and everything…Jack told me…”

“Jack?” Mike says. 

The man takes a deep breath and looks closely at Leo. Too closely Leo thinks, as if he recognizes him. Mike types into his phone.

“This came out six minutes ago. You’re on the news.” Mike says, holding out the phone for Leo to see. 

Leo looks at the ABC News article and sees his face staring back at him. He recognizes the photo from an Instagram post from six months ago. 

He watches the first cart drive away. The second one idles. 

“We have to go,” Mike says, indicating the cart. He holds his hands out. 

Leo looks around the room and realizes everyone else has left. He looks at the cart idling on one side of the room and now realizes there’s an opening on the far side. It was so quiet opening that Leo didn’t realize that’s where the sudden burst of cold originated.

“Where are we going? When are we coming back?” Leo asks.  

“Coming back? Leo, you’re wanted for murder.” Mike says. 

A BRRRAT-A-TAT in the distance. BRRRAT-A-TAT. Mike looks to the ramp. Leo takes a millisecond longer. It’s a burst of gunfire. 

Then a SCREECH of tires echoes across the room. 

“Shit! Get in the cart!” Mike yells. He runs toward the cart. Leo freezes as he sees the blacked out late-model suburban tear down the ramp and make a hairpin turn, tires screaming, into the room. It takes a moment for the large vehicle to orient itself correctly, but Leo sees a large weapon hanging out the passenger side window. He runs toward the cart just as Mike falls to the ground, face-first, his head bouncing off the concrete. It’s then that he hears the BRRRAT of the semiautomatic weapon. Leo does a one-eighty and dives behind a concrete pillar supporting the ramp entrance. 

The cart drives away and Leo feels all hope leave his body. But then it slams grate-first into the wall and the driver slips out of the front seat, the back part of his skull imploded from a well-aimed round, and his torso oozing blood. He was dead before he even turned back to look at the suburban. 

Pushing himself as far as he will go into the concrete and shaking uncontrollably, Leo pulls out his phone to dial…someone. 911? But isn’t he being hunted by the police? His mom? But what can she do from San Jose? 

As he looks at his phone, a text pops up from Celia. I saw you ON THE NEWS! I think it’s my fault!

Then another one. I’m so sorry. But please turn yourself in, Leo!

The phone drops out of his hand and falls on the concrete. He reaches to the back of his waistband, but the pistol Jack had given him is still in the van. 

He hears the suburban doors open. 


Copyright Chris McCarthy and MDA Press, 2024, Graphics by Chris McCarthy with Imagen3.

Exponential Threat, Part 4

By Chris McCarthy


CRAACK. Another fist pounds into the door, leaving another huge indentation. Lisa looks at the marks in the steel door and her mouth drops. She looks at Ambassador Trong with a look of disgust. 

“You had him kill the magno-puppy?” Lisa asks.

“Yeah. I did.” Trong responds. “Do you have any idea how dangerous those magno-puppies are? How big they get? Besides puppy is a misnomer—they’re more like bears. There’s no place for those beasts on planet Tumis.” 

Lisa looks at Winston. “It’s all my fault. That innocent creature is dead because of me.”

“Well, we can’t do anything about it now. Besides I’m the idiot who helped you catch it. It’s not all on you.” Winston says.

“Guys, enough. Open the door, Sal,” Amanda says. 

“What do you mean open the door?” Salamander looks from the door back to her. 

“I mean, open the door. Like I just said.” Amanda responds, walking over to the door. 

“Fine.” Salamander says. “Why delay our inevitable gruesome deaths, right?”

Salamander taps a button on the command interface screen. The door at the back of the bridge slides open. On the other side is a hulking half man, half mechanical monstrosity. He has a powerful titanium exoskeleton frame grafted onto his muscular body, with pulsing bright blue energy lines pulsing visibly between the seams. One arm is an interchangeable weapons system that in its current form identifies as a sleek plasma cannon, softly humming with power. One eye can flip around revealing a powerful laser. He’s just under seven feet tall and weighs four hundred pounds. 

“Holy sh…” Salamander says just before he passes out, falling to the floor of the bridge with an echoing thud. 

Amanda tries to turn her head away from the blue-hued monstrosity but can’t tear her eyes away. She just ends up turning her head slightly in Lisa’s direction. “Help him, Lisa.” 

Lisa looks from Amanda to their giant visitor, speechless, then over to Salamander. “O…K.” She walks over to Salamander and takes a knee, gently slapping his cheek to wake him up.

Winston looks at his hand. Whatever he did with the blue energy stream earlier, he can no longer do. He says, “Well, I guess this is it, everybody. Really wish I hadn’t helped Lisa steal that mango-puppy because now Ambassador Trong is going to have this biomechanical freakshow kills us all.”

“That’s rich coming for a metal head like you.” Trong says. 

“Hey don’t call him metal head, you anti-mech bio-traditionalist. Like you’re not going to seek augmentation when you get old and ugly. Or I should say uglier.” Lisa says. 

Winston continues to himself, “Why do you always try to impress the wrong women? Three hundred years old, eleven marriages, and you still make the same mistakes. I should have just stayed out of it.”

This hits Lisa. “Excuse me? Stay out of it? Catching mango-puppies was your idea. How convenient for you to forget that now.” She points at the biomechanical monster in the doorway.  

Amanda puts a hand on Trong’s shoulder, “Man, he looks like he took a nosedive off the ugly tree and hit every branch on the way down before landing in a pool of, well, ugly. I mean, talk about darkening a doorway, jeez. This guy’s probably in the dictionary for that term.” 

“I don’t think they have terms in the dictionary. Just words right?” Maritha asks. 

“Will you shut up, Maritha?” Trong says. 

“Wow, you let him talk to you like that? You wave flags for this guy?” Amanda asks. 

Winston walks up to Lisa, “But the way, I’m no longer in love with you.”

“What?” Lisa says. 

“I’m not sure I was ever really in love with you.”

“Great, thanks for that. I’m gonna lose so much sleep over this realization. I would NEVER date you. Just fyi. But you don’t care anymore so that’s great.” Lisa says, with a pettiness that shocks even Amanda. 

Winston continues. “I think I’ve just been trying to prove to myself that I’m…still a human. Then, for a moment, having otherworldly power and shooting blue laser beams out of my hands, I thought I’d transcended my hybrid nature becoming something more. But that was just a fluke. I have to come to terms with the fact I’m neither human or machine. And that proof is standing in the doorway.”

Lisa takes in Winston’s admission and looks over at the blue mech in the doorway, her eyes following the blue pulses of energy in the cracks of his titanium frame. 



Chase, who has been sitting this whole time, stands up and turns around to face the doorway. He jumps back. “Jesus!” 

Chase gathers himself and nods at Trong. “What’s with death incarnate over here. And why is he just standing there. Is he waiting to be invited inside?” He looks at the mechanically augmented man standing the doorway. “Hey, God’s mistake, are you a vampire?” 

“No, he’s not a vampire. His name is Olg. He’s a terrifying specimen who’s going to kill all of you.” Trong then turns to the mech, embarrassed. “Come inside.” He waves him in dismissively. 

“Olg?” Chase says. “That is the dumbest name I’ve ever heard. Other than Trong, of course.” 

The crew laughs at this joke, making Trong uncomfortable. 

“Guess they modified everything but the brain, huh?” Amanda says. The laughter continues.  

“Looks like he doesn’t understand English? I’m not fluent in dumb, otherwise I’d see if that worked.” Salamander says.

The crew is in tears, including Amanda, who laughs so hard she leans on the wall for support. They’re tee-ing off on Trong and his associate. 

“It’s called gallows humor, Trong. Feel free to laugh with us. Release the tension. It’s stressful murdering a whole crew of innocent people, isn’t it?” Chase says. 

“I said you can come in, Olg!” Trong says.

“I said you can come in Olg!” Lisa repeats in a mock-serious voice, to everyone’s uproarious laughter. 

Olg takes a few steps inside the door. His arm cannon whirs and lights up a brighter blue. His eyes turn red and get larger.

“What is your command Ambassador Trong?” Olg says, his voice so terrifyingly low that it seems to shake the room. 

The crew get so silent you could hear a pin drop. Trong smirks. 

“Kill them all.” Trong says. 

Amanda stands frozen. “I guess this is it.”

Then Chase takes a knee. “Here boy.” 

Olg looks at him curiously, his arm cannon raising up to Chase’s chest level. Then suddenly, Olg gets on all fours, running around and bouncing off walls and consoles and the viewport. Amanda and the crew look on, in confusion. 

Chase watches Olg bout around the bridge. “Trongy, did you know that magno in magno-puppy is actually short for magno-morph?”

“Magno-morph? What does that mean?” Trong looks around, lost. “Maritha, what does that mean? What does that mean?”

Winston touches his temple then whispers in Amanda’s ear. 

“It means these animals can turn into any other creature they see, a defense mechanism they can access if they are in enough danger.” Amanda says.

“No. No, that can’t be…” Trong says. 

“Salamander, get us out of here. Go back to wide orbit. We’re leaving.” Amanda says. 

“God you’re good at leading, Amanda.” Salamander says. 

“Keep that kind of fawning inside Salamander, but I appreciate it.” Amanda says. 

Sal runs over to the front of the bridge and hops into his seat and hits a few buttons for new coordinates. 

“Lisa, can you chart a safe course out of here? I want to make sure those ionospheric disturbances don’t cause any more problems for us on our way out.” Salamander says.

“Look at you, Sal!” Winston says. 

“On it.” Lisa jumps into her chair, hopping over Liam’s body on the floor of the bridge. She activates her holoscreen, which pops out in front of her face. She looks at it. “Everything looks good, Sal. Just a couple of quick modifications to the flight plan and we’re good to go. Initiating now.” 

“So you’re saying…that’s the…” says Trong. 

“Oh yeah, you’re still here.” Amanda says. “Yeah. That’s our magno-puppy. To be honest I thought he’d kill and eat us all, but it seems like he’s… a part of this messed up family.”

“I don’t buy it. You must have hacked into his system somehow.” Trong says. 

Then Olg transforms into the magno-puppy, his body shaking, the metal exoskeleton seamlessly being replaced by hair. Back on all fours now, he sticks his tongue out and runs over to Chase, who reaches down and ruffles the dog’s face fur with both hands.

“Who’s a good boy? Oh…yes…that’s my good boy. Wait…” Chase looks between the animal’s legs a bit closer. “Who’s a good girl? That’s my good girl.” 

Lisa runs over to the five foot tall puppy. “I’m so glad you’re alive!” The puppy turns to her and starts licking her face. 

“Oh, you’re so sweet. Yes, give me all those kisses…Wait, is that? Is that…?” Lisa asks. 

“It’s blood,” Amanda says. 

“Ewww.” Lisa blinks both eyes quickly and her holoscreen pops up, already with a front facing camera feed running live. She looks into it at her face and wipes the blood from her lips and nose. “That is so disgusting…” She turns to the puppy who stands back from her, chastised. “You’re lucky you’re so cute.” 

The huge bear-like puppy spins around in excited circles then runs to Salamander and jumps in his arms, knocking him down to the ground. 

Trong takes in the scene. “What is…happening?”

Chase says, “The figs.” 

“Huh?” Trong says.

“When you and your retinue were boarding, I went down to check on our little…our huge… gal to make sure she was secure down in the brig—and to fuck with you by not being there for that fucking song and dance reception bullshit. Anyways, he was curled up in a corner. Turns out the gal had a ridiculous case of gas since we’d been feeding her popcorn for six days straight. Note to the crew—popcorn is not good for puppies. Anyways, I gave her some Parthian figs and won her over.” Chase says.

“And that’s when your freak of nature science project showed up at the ventral airlock—you thought you were being so slick, sneaking him aboard through another entrance while the crew was distracted on the bridge getting ready for receive you,” Chase continues, pacing away from Trong. He turns on his heels, the detective delivering his final blow. “But unluckily for you, our puppy, having had some of the figs, had gotten her appetite back.” 

Chase looks over at the puppy. “Isn’t that right, girl?” The puppy jumps down from Salamander’s chest and runs full speed back to Chase, who falls to the floor with her and rolls around. 

Trong shakes his head. “I’m not sure I’m catching the logic. She ate him…then became him?”

Amanda jumps in. “I think what he’s trying to say, Trong my good man, is that your human specter of death scared our puppy so much that his defense mechanisms kicked in and he morphed into a carbon copy. Then, spurred on by the taste of figs, he ate your man.” 

“So did he eat my man when he was a dog or did he eat him after he looked exactly like him…I’m just trying to get the picture here.” Trong says. 

“Don’t think too hard about it. It’s something I’ll never unsee if that helps.” Chase says. “Hey crew, I’m thinking we name him…Olg.”

The crew all nod and agree. “Excellent idea,” says Lisa.

Trong shakes his head, resigned and annoyed. 

“Well, isn’t this a…very strange and dysfunctional domestic picture. I think it’s time we took our leave…Maritha, what are you doing? Do not play with the creature.” 

Maritha is down on one knee waving her flags at the puppy. She looks up at Trong. “Oh come on, Trong. She’s so cute. Why can’t we ever have fun when you’re around?” 

“That’s Ambassador Trong or sir to you, Maritha. You insolent…” Trong says. 

Maritha stands up, “Ambassador? Are you sure about that?”

Trong takes a step forward. “Of course I’m sure… What do you…?” 

“Well, you’ve lost your entire retinue… And by Legion dictates, that means you have to relinquish your title.” Maritha says. “You’ve lost your people’s faith.”

“But, you’re still here, Maritha. I still have you. You’re on my side, right?” Trong says. 

“Nope. I don’t like you.” Maritha says. 

Amanda covers her mouth to try to hide her laughter. “Hah!” 

Amanda’s crew all cheer as Trong loses his last supplicant. He looks totally alone standing on one side of the bridge. 

Amanda walks over to Edwin and puts her hand on his shoulder. “Edwin, things just arent’t working out for you are they? Is this how you thought our reunion would go?” 

“No—hey, look, everyone. I think we started off on the wrong foot. Let’s reset.” He turns to Amanda and walks toward her, both arms extended. “Amanda, so good to see you!”

Amanda backs up and pushes Trong’s arms away. “Are you delusional? You were about to kill us.”

“Yeah, how are we supposed to get past that?” Chase asks. “Look, I see you sort of as a distant step-son, re your mom, of course, and…”

“What does that mean? RE your mom? I don’t understand…” Trong says. 

Chase looks around the room, then at Amanda, who puts her face in her hands. Her father’s infidelities are no secret to her. But Chase quickly tries to cover. 

“Nothing. Sorry—I just mean I like you a lot kid. I remember driving you and Mandy to school. You were always nice, just a bit clueless. But now it’s time to take the hint.” Chase says. 

“What’s the hint?” Trong asks. 

“Oh, that the puppy is going to eat you.” Winston says, as the puppy licks his face. 

Trong runs to the hallway exit, but it slides shuts just before he gets there. He looks over at Salamander. 

Salamander looks to the rest of the crew. “That’s the coldest thing I’ve ever done.” 

“Hell yeah, greenie.” Chase says, proud of Salamander’s assertive move. 

“Look at us,” Amanda says, looking around the bridge at the faces of her crew, a proud look on her face. “Coming together, like a real spaceship crew, over a thirst for vengeful blood. I could almost…No, I’m not going to do it. I’m not going to cry.” 

Lisa looks on empathetically. “Oh my gosh. Don’t cry, sis.” She walks over and hugs Amanda, moved by her emotional response. “I feel like we’ve gotten so close.” Both women hold back their tears. 

“What…the fuck…” Trong says, walking backwards to the wall, trying to keep distance between himself and the crew who seemed so ragtag a few moments ago but now seem to revel in a sudden bloodthirsty confidence. 

Trong trips on the foot of Lisa’s station. He trips but regains his footing and falls slightly against the back wall of the bridge, his face slamming against the aft viewport. 

The huge puppy takes several heavy steps and bares his teeth at Trong. 

Trong gulps. 


Chase and Amanda sit on the bridge. 

She’s in the captain’s chair and he’s in Salamander’s. The rest of the crew sit in a circle behind them playing with Olg. 

“You know, when I was young, my dream was to work as a crew member on your ship.” Amanda says. “I mean, before…”

Chase turns to her. “Before everything went to shit?” 

Amanda nods affirmatively.

“By went to shit, do you mean your two decades long campaign of drinking and womanizing yourself through the galaxy while leaving me and mom behind?” 

Chase looks at her, unsure how to take this, and for once has no words. Then Amanda cracks a half-smile and shakes her head.

“Well, I guess we’re here now. And maybe we can make the best of it.” Chase continues. 

Amanda smiles. Twelve years into her career as a ship captain in the Legion, she’s intimately familiar with the punishing toll the job takes on people and can see her father better than she ever could before. 

“Do you think we were too hard on him?” Amanda asks.

“Who?” Chase is genuinely confused. “Oh…him.” 

He looks out the viewport and angles his head down a few degree to look at the bow of the ship. Wearing a white thermasuit and pressurized helmet, Trong is attached to the front of the ship. 

“I mean, he’ll be fine as long as we don’t go too fast.” Chase says, leaning back in his chair. 

“That’s what I was thinking,” Amanda says.” 

Amanda smiles, enjoying the moment with her father. 


Copyright Chris McCarthy and MDA Press, 2024, Graphics by Chris McCarthy with Imagen3.

Exponential Threat, Part 3

By Chris McCarthy


Lisa looks on curiously as Winston stares at the blue glow emitting from his right hand.

They lock eyes and Lisa tilts her head slightly. Winston registers that she’s asking him if he’s going to do something. He looks at Ambassador Trong and his two henchmen and a chastised Maritha holding her ridiculous ribbons down at her side, then back at Lisa. He hides his hand behind his back and shakes his head, unsure.

Amanda takes a step toward Trong, who sits in the captain’s chair facing the inside of the bridge. 

“Edwin…” she says. 

“It’s ambassador Trong,” says Trong.

“Right,” says Amanda, taking another step forward, “Ambassador Trong. Let’s leave my crew out of this.” 

“Amanda, every single person—and half person and whatever the green guy would call himself—is guilty of transport of an illegal species. Why would I do you of all people any favors?” 

Amanda looks around the bridge. Everyone watches silently, Trong’s people waiting for a signal to take action, and Amanda’s people waiting for a sign of hope. 

“Why don’t you just take me in and let my crew continue on with their mission?” Amanda asks, her anxiety making its way into the pitch of her voice. “I don’t think Admiral Flake would…”

“Admiral Flake—hah!” Trong spits the words out. “Admiral Flake is as corrupt as they come. He has no authority over me. His splinter of the IL is on the chopping block. He’s from unlanded stock.”

“Whatever. I don’t care about politics… Look, just lock me up and throw away the key,” Amanda says, “Let my crew and my father go. I’m the one you want, right?” 

Trong stands up and gets in Amanda’s face. “What I want is my birthright! I want my planet back. Can you give that back to me, Amanda?” 

“Look…” Amanda says, stepping back but wearing a contrite look on her face. 

“I didn’t think so!” Trong yells.

Chase takes a step forward, “I think I can help here…”

“Sit down,” says Trong, pointing at him derisively. 

The ship passes through a particularly bright pink ionospheric aurora. As they do, the ship quivers noticeably, the Cardanian steel frame vibrating to the touch even on the interior of the ship. 

“Is that normal?” Chase asks, looking around at the wall and the ceiling of the bridge. 

“Aren’t they just light curtains?” Salamander asks, looking at the light displays as they hit a patch of green. 

Maritha looks out the viewport, “Happens all the time. It’s just an electromagnetic pocket. Sturgis, look at these novices. What are you guys like a local inter-moon transport ship or something?” 

“Yeah, they were. Until I showed up.” Chase says. 

Amanda gives him a tight smile, “Us showing up is the best thing that ever happened to you.” 

“The best thing that ever happened to me? You blew up my home and almost killed me.”

“Yet, here you are. You got off easy.” Says Amanda, turning to look out the viewport and taking a step back when she sees how intense the pink aurora has become.

“I become part of the crew and suddenly we’re all bounty hunters,” Chase says, gliding his hand through the air, indicating each member of the crew. 

“Wow.” Says Maritha, taking in the father-daughter dynamic. 

“I said sit down, Chase! And everyone shut up.” Trong says, taking a step forward. “Guys.”

Liam and Sturgis snap-to and grab Chase by either arm and sit him down at Winston’s station in the center of the bridge. 

“Easy, guys. We’re all on the same team here.” Chase says just before they slam him into the seat. 

He looks around at Winston’s console and notices the neural dock headpiece, then he looks up and instinctively pulls his head back as Liam pushes his blue chryo-blade in his face. 

The sharp energized blade hums as Liam gently but threateningly waves it in front of his face. Looking past the knife to the other side of the bridge, Chase notices Winston surreptitiously looking down at his glowing hand.

“I mean, we’re not on the same team, obviously,” Chase continues. “But it’s just something you say, you know what I mean? Maybe you don’t. You don’t seem so bright. He’s the one who does all the thinking huh?” Chase says, nodding at Sturgis. “Since he’s a computer. Best thing to happen to dumb guys right?”

“Hey, I’m holding a knife in your face.” Liam says, holding his face close. 

“Good lord. You need to loosen your trade restrictions, because legalizing gum would help you people out a lot. Your breath could kill a small animal. Maybe not a fully healthy one. But one that’s already injured or sick in some way. One breath from you would just be the final straw. What a way to go. Death by breath.” Chase says, turning his head away from Liam.

Liam pushes the knife right against Chase’s neck, “You insolent, past-his-prime, old…” 

“Owww.” Chase says, grimacing in pain. “Thanks…I forgot… to shave… this morning.” 

“Hey—stop that!” Amanda says.

“Enough!” Trong walks over to Chase’s seat and holds a finger in Liam’s face. “Don’t let your prisoner get your goat.” 

“Sorry, Sir. I’ll do better.” Liam says, pulling the knife off Chase’s neck. 

Salamander looks over at Winston and Lisa and notices Winston’s glowing hand. 

“Shhh,” Winston says. Salamander also notices that Lisa has taken the comm off her belt and holds it so the sharp angular side shows between her pointer and middle fingers. 

Salamander looks nervous and whispers, “Are we actually doing this? Ok, I can do this. Can I do this? This is exciting, right?” 

“Keep it down,” Lisa says.

Salamander glances at the display on the viewport. “Wait a minute…when they boarded, the ship prepped life support for five life-forms.” 

Lisa scans the bridge, “I only see…four.”

Winston, “So, what does that—?”

Amanda looks over at Salamander and the crew, “What?” She waves her hand dismissively for them to stop talking.

Chase slams the neural dock headpiece into Liam’s face. He drops the chryo-blade and falls back, clutching his face. “Aaaah. You son of a…” 

Trong takes a step back as Sturgis runs up to Chase’s seat, eyeing Trong for his command, as his eyes turn an even brighter shade of green. Trong nods to Sturgis and says, “Might as well kill him first.” 

“Why did you guys all just stand there? Wasn’t that a signal?” Chase asks. 

“No. That wasn’t a signal. I was waving my hand derisively at my crew like I always do. Why are you always jumping the gun? It might help to think things through once in a while, Chase.” Amanda replies.  

“What is it with all of this talking?” Trong asks. “It’s like you think I don’t have full control of your ship. Maybe I need to show you that I’m serious.” He looks straight at Amanda. “Liam, kill Chase.” 

Liam smiles and looks over at Sturgis, who laughs giddily. “With pleasure,” he says as he swings his knife through the air. The knife turns into a long sword with two handles, which Liam now wields with considerable skill, windmilling it around in the air, the blade hissing loudly as it cuts through the condensation in the air. 

“Wait, Trong, can we talk about this?” Amanda says, terrified. 

Chase gulps as Liam swings the sword. 

Trong looks at Liam, “What are you waiting for?”

Liam pulls the sword back with both hands and starts to swing. 

Chase closes his eyes. Then suddenly feels something heavy in his lap. He looks down surprised to see it’s Liam. 

The ship quakes again and everyone shuffles a bit to maintain their footing. The quake knocks Liam’s lifeless body off of Chase’s lap onto the floor. 

“What the…” Chase says in confusion. 

Then he looks up and sees Winston holding out his arm, a blue electric field encircling his extended hand. 

“Oh my god, Winston,” says Lisa. “You’re like…powerful.”

“Sturgis!” Trong says, backing away into the wall behind him. 

Sturgis looks from Liam to Winston with disbelief in his eyes, which have now turned an even brighter shade of green. 

Winston confidently steps toward Sturgis. He holds out his hand dramatically and… nothing happens. He does it again. 

Nothing. He smiles nervously. 

“Oh we’re no longer in the EM pocket,” says Maritha. “Clearly, the rapid-conversion circuitry in your arm, coupled with reinforced biological tissue to withstand energy transmission enabled you to transform the electromagnetic flux into directed energy. But now that you have no excess energy to pull from, you’re essentially an empty well.” 

She looks around the bridge as everyone is surprised at her explanation. 

“I’m a cybernetic interface researcher and plasma physicist.” Maritha says. 

“What, you thought she just waved flags around all day?” Trong says. “My girl’s wicked smart. She’s the one who made Sturgis what he is today.” 

Amanda looks from Trong to his murderous cyborg and his brilliant pageant guard and reads the looks on her crew’s faces. And for the first time senses impending doom. 

Winston looks out at his arm and extended hand and drops it to his side. 

Sturgis chuckles and shakes his head then locks eyes with Winston. Oddly, Winston can’t look away and he starts to sweat. A vein in his temple bulges blue. He can’t move his eyes away from Sturgis’ gaze as he grimaces in agony. Sturgis takes another step forward. 

Amanda look on helplessly. 

“Ambassador Trong, please stop. He’s hurting him.” Lisa says.

“Oh no. He’s killing him.” Trong says.

THUD THUD THUD. Heavy footsteps reverberate down the hallway.

“What’s that?” Salamander asks. 

Trong smirks. “That’s one of my men.”

“It’s the fifth one the life support system detected when they boarded.” Salamander says, looking at the display. He double takes then looks closer. He toggles to the camera feed just above the door in the hallway. 

“Oh shit. It’s a Biomech Executioner.”

Salamander pulls a holoscreen copy of the display off with a swipe of his finger and spins it around for Amanda to see. The video feed shows a huge hulking man. One gigantic hand wields a battering ram and the other hand isn’t there. In its place is an arm cannon, with multiple segmented plates, which can slide and realign, revealing different weapon configurations from a focused plasma lance to wide-dispersion energy cannon.

“Oh come on!” Says Amanda.

“Yeah. Can you say overkill?” Chase says.

“You brought an Executioner with you

“We had him enter the ventral side of the ship at the same time we boarded the port. Sent him straight to the brig, where I knew you’d have that magno-monster.” Trong bites a nail then examines his finger. “He killed it immediately. Now he’s going to come up here and finish the job.”

There’s a final THUD in the hallway. Then the sound of a metallic arm smashing against the door. It leaves and indentation.

“Ok, now we’re definitely all dead,” Salamander says. 

Winston tries to eek out a word but can’t say anything. 


Copyright Chris McCarthy and MDA Press, 2024, Graphics by Chris McCarthy with Imagen3.

Red Lines, Part 3

By Chris McCarthy


Leo feels the cold of the kitchen down in his bones as he looks up at the large Russian man standing above him. Despite his fear, he looks directly down the barrel of the gun then down at the floor. It doesn’t feel how he thought it would feel. It doesn’t feel like anything. In that moment, Leo realizes that his emotions aren’t him. He’s something else. He’s the thing observing the emotions. The emotions are warnings, indicators that he can observe and decide how to respond to with the part of himself that watches from behind. The part that’s actually him. The irony that these thoughts appear as his body succumbs to acute anaphylactic shock and he’s losing control of his motor functions, shaking uncontrollably, and his tongue is rolling back into his mouth down his throat is not lost on him. 

The things you learn at gunpoint. 

The Russian takes another step forward and presses the gun into the center of Leo’s forehead. But he can’t feel the cold of the metal. He only feels the pressure because his forehead feels thick as if there are layers of cotton between his skin and the barrel of the gun. Then Leo sees the grotesque image of a large knife blade exiting through the front of the Russian’s stomach on the right side. The Russian turns around, but the cop, with a surprising burst of energy pulls the knife out of the man’s back and slides it across his neck, in a soft supple motion. It seems to be done with such light pressure that surely it hasn’t done any harm. But then the black red hairline of the cut appears and a curtain of blood cascades down the man’s neck, his shirt almost immediately soaked with blood. Just as the man’s eyes register what’s happening, he expires, leaving behind an odd look of surprise on his face after it follows his body and slams to the floor. The cop drops the knife to the floor with a clang. He hobbles over and leans on the counter, breathing heavily, blood around his mouth. 

That’s when the girl runs into the room and says, “Help me untie the rest of the girls. We need to get out of here. The mean one will be back any minute now.” 

The cop looks at Leo. “What’s wrong with you?”

Leo hears himself trying to say… something.

The cop takes another two breaths, gathering himself, then pulls Leo’s shoulder forward, trying to get his arm around his neck. Then Leo’s feet feel like bricks dangling on lengths of rope and it’s all black again. 

Leo’s vision comes and goes. He sees something bright—perhaps the moon. Does he see clouds? He thinks he’s outside, and he’s moving. It’s so cold. There’s a high-pitched worried girl’s voice somewhere on the periphery of his awareness. The edges of his vision cloud and uncloud. 

Then Leo feels something pushing on his back and head. It’s the hard leather of the backseat of the police car. Then, a sharp jolt in his thigh. Leo is now cognizant that his hands are at his throat, desperate to somehow coax a breath through. But he can feel them again. And just like that he breathes in, the cool air going down his throat. His chest and neck muscles relax as his stomach now contracts pulling the cool, life-giving air inside. The whispered voices now become clear as he snaps back. 

The car starts. He sits himself up, leaning his shoulder against the door, and sees three girls around twelve or thirteen years old scrunched together into the seat next to him.  He looks forward and sees another two girls in the front passenger seat. 

He hears something but it’s unclear. Then he realizes the cop is talking to him. “We thought we lost you.” 

To Leo’s left, the three girls sitting there are entangled, holding each other close, one of them, who seems to be a year or two older, comforts the other two, one of whom balls silently. Leo thinks they look like tears of relief. Not that much relief. Just some relief. Leo feels a low beating thud in the back of his head. It’s been a long day.

As he looks down at his hands, which feel less puffy and heavy, he notices the cop’s darting looks into the rear view mirror. Leo sees the backs of the two girls heads in the passenger seat and counts five girls total.

That’s when he hears the sirens.

“Who’s after us?” Leo asks.

“It’s the police,” the cop answers. Leo detects no irony and no emotion in the response but he can tell the cop is concerned with this development.  

“What? The po— but aren’t you the police?” Leo asks, his mind racing now.

“Yeah. A different kind.” The cop says. 

“What do you mean a different kind?” Leo asks, swinging his head back to the front after looking out the back window. 

The cop is determined, now, as he reaches over to check the seatbelt of the girls in the front seat. “Let’s make sure this is tight,” the cop says with a warm smile.

The cop speaks quietly into his radio. Leo hears disconnected phrases—“a body” and “cleaned up”—and he connects the comment to Cam, instantly remembering the dead body lying in the cold dark kitchen. He’s about to ask about Cam, whom he knew for about thirty seconds, not even enough time to recognize his face if he saw him again. He recognized his body on the kitchen floor from his paunch…

“Hang on.” Says the cop. 

He jerks the wheel and Leo is pulled to the right of the car, pushing his forearm out against the window instinctively.

The cop drives the cruiser with no lights on and crosses over two lanes on the street in a downtrodden area of the city. He shoots down an alleyway between an abandoned old brick building that could be thirty or a hundred years old and a small commercial complex, one of those nondescript complexes filled with mom and pop mechanic or specialty car repair shops covering for who knows what. But even these seem like they haven’t seen much business in years. Leo instinctively looks for street signs to try to find some sense of location. But the area is so poorly lit that the one small sign he sees for the alleyway they travel down isn’t legible.

The cruiser rips down the alley. The cop makes a left turn at the end of the alley turning onto another dark street. 

Leo looks behind him. He still sees the blue and red lights. The car is still pursuing them. It’s then that he feels his phone vibrating in his pocket. He pulls it out.

Fifteen missed called. Thirty seven text messages. All from Celia. 

He quickly glides through the text messages. One of the earlier ones says, “What the hell is going on? Are you ok?”

Then another one catches his attention: “I saw everything!”


Red Lines GPS eps 4
Red Lines GPS eps 4

Leo is still looking at his phone screen reading Celia’s text message when he hears the cop speak low into his radio. The cop speeds up if that’s even possible, takes another quick left down an alley way, comes out on Main Street, hits a right, and Leo looks behind him realizing the police cruiser is no longer behind them. Then the cop takes another left and pulls into a parking lot between a small mechanic shop and a dirt hill. Leo still hears the siren but it’s becoming more distant. 

A chainlink fence covers three sides of the parking lot and as the cop drives into it and stops the car, Leo can hear a steady rush of traffic coming from somewhere. He looks up the hill and can just see the steel guardrails of the 405 freeway. 

He slides his phone back into his pocket, but not before the cop notices.  

“What the—?” The cop coughs blood and struggles to get the words out. “Did you call someone?” 

“No—I just have some messages from my girlfriend…” Leo says. 

The cop doesn’t respond because he’s distracted looking at a white, early 2010’s minivan parked in the darkness. A man steps out of the driver’s seat and shuts the door behind him. He walks around the side of the car and opens the sliding door in the side of the van. 

The cop undoes the seatbelt for the two girls in the passenger seat. 

“OK, everyone get in the van.” He looks at the girls to his right with a tight smile. “It’ll be ok. You’re safe now.” Then he looks over to the girls in the back seat and gives them the same tight smile. Leo notices just behind the smile is a pained grimace. 

The girls all hop out and make their way to the van. The driver of the van helps them in and shuts the door behind them.

“Who is that?” Leo asks, sticking his head through the opening in the plastic divide between the front and back seats. 

“You go too,” the cops says. “I’m staying behind.” Leo, for the first time sees that cop has a wound in his lower let stomach right about his hip bone. Dark blood oozes out.

“Shit. I didn’t know you were hurt that bad.” Leo says. 

“Get in the fucking van.” 

Leo watches as the van driver runs up the short hill to the freeway. He catches the glint of a mirror of a car parked right above them on the side of the freeway. The man is leaving. 

“Look, you can get in the car or you can wait here with me. That officer is only a few minutes away form finding us. They’ll have a bird in the sky looking for us in another minute…” 

Leo feels his face flush. “Wait, you’re a cop right?”

“I used to be.” 

“What does that mean? You’re wearing a uniform.” 

“None of that matters right now. The people chasing us—those officers, if you can call them that—they work for the same people as the guy you took care of earlier.” The cop says. 

“So…what…I’m fucked? Is that what you’re saying?” Leo asks, feeling his face flush.  

The cop pulls a device out of the center console and hands it to Leo, wincing as he does it. 

“It’s an encrypted GPS device,” the cop says. “Just follow the directions on the screen.” 

Leo turns the cellphone-sized device over in his hands. 

“What? I’m—I’m supposed to drive?! You’re leaving me and I’m driving those girls…? Where the fuck am I going?!” Leo asks. 

The cop gestures to the girls in the back seat of the van, all of whom are looking out the back window at the two men talking. 

“You need to go now.” The cop says.  

“Why do you need to leave?” Leo asks.

“I’m not leaving.” 

“What are you going to do then?” 

“I’m gonna delay them for as long as I can.” 

Leo looks around the parking lot. He thinks about running down the driveway and into the shadows of the alley. He looks up at the freeway. 

“You can’t run now. Only way out is to follow the plan. They’re coming for us.” The cop says. 

“What’s the plan? I don’t know what the plan is.” Leo says, getting increasingly anxious. 

“Just get those kids to the location on that device. There are people there who will take care of you. Leo, you can do this. You have to do this.” The cop says.

The cop swings his door open and steps out. He opens the drivers side back door. “Come on. Get out.” He says.

Leo shakes his head wondering how many days it’s been before remembering it’s only been a few hours. He steps out of the car. 

“I just realized I don’t even know your name,” Leo says. 

The cop walks to the trunk and pops it open. “Call me Jack.” 

He reaches in and pulls out a pistol and hands it to Leo. “Go. NOW!” 

Leo slips the GPS device into his pocket then reaches out and grabs the gun by the cold heavy barrel. Now that he knows him as Jack, Leo wonders if he has a family, friends, children. 

Jack nods and Leo walks to the van. 

“Be quick but try not to speed.” Jack says.

Leo opens the driver’s side door of the van and puts a foot up into the footwell, turning to Jack. “What the fuck does that mean?” 

Jack chuckles then winces and leans back into the trunk. As the trunk swings shut, Leo sees the shotgun in Jack’s hand. 

Leo starts the van’s engine. “Put your seatbelts on.” For some reason he’s uncomfortable making eye contact with the girls who sit quietly in their seats in the back of the three-rowed van. One of the girls helps another put her seatbelt on. Leo takes a deep breath and puts the van in drive. 


Copyright Chris McCarthy and MDA Press, 2024, Graphics by Chris McCarthy with Imagen3.

ZotSun: UCI Entry in the Formula Sun Grand Prix


Design of the 2025 Formul Sun Competition Vehicle: The UCI Solar Car Race Team presented the design of their 2025 competition vehicle at the end of the Fall quarter, December 10, 2024.  A pdf version of this presentation is presented below.  

They will build this vehicle during the Winter quarter 2025 and test it, train drivers and prepare for the competition in Summer 2025.  Here is the list of college race teams that they will be facing: Formula Sun Grand Prix.

Please support their efforts by donating to the UC Irvine Solar Car Project Zotfunder:


Fall 2024 Solar Car Design Presentation

These slides describe the race car that our UCI Solar Car Racing Team will begin building in January. Please take a minute to scroll through the slides:

UCI Anteater Baja Racing: Five Months to the Competition


Design of the 2025 Baja Competition Vehicle: The UCI Anteater Baja Race Team presented the design of their 2025 competition vehicle at the end of the Fall quarter, December 10, 2024.  A pdf version of this presentation is presented below.  

They will build this vehicle during the Winter quarter 2025 and test it, train drivers and prepare for the competition in mid Spring quarter 2025.  Here is the list of college race teams that they will be facing on May 1, 2025 at the Caterpillar Testing Facility in Marana, AZ, outside of Tucson: Baja SAE Arizona

Please support their efforts by donating to their Anteater Baja Racing Zotfunder:


Fall 2024 Baja Design Presentation

These slides describe the race car that our UCI Anteater Baja Racing Team will begin building in January. Please take a minute to scroll through the slides:

UCI Anteater Electric Racing: Six Months to the 2025 Competition


Design of the 2025 EV Competition Vehicle: The UCI Anteater Electric Race Team presented the design of their 2025 competition vehicle at the end of the Fall quarter, December 10, 2024.  A pdf version of this presentation is presented below.  

They will build this vehicle during the Winter quarter 2025 and test it, train drivers and prepare for the competition in Spring quarter 2025.  Here is the list of college race teams that they will be facing on June 17, 2025 at the Michigan International Speedway: Formula SAE Electric.

Please support their efforts by donating to their Anteater Electric Racing 2024-2025 Zotfunder site:

EV Zotfunder
EV Zotfunder

Fall 2024 EV Design Presentation

These slides describe the race car that our UCI Anteater Electric Racing Team will begin building in January. Please take a minute to scroll through the slides:

Getting to Know the Arduino IDE

By Brandon Tsuge,


In this post, we will see how to install the Arduino software and use the integrated development environment (IDE). For this series, I’m going to be using parts from the Arduino Starter Kit


Windows Installation

First, go to Arduino software download page here. For windows users, click on the installer option. Mac users will only have one option.

Arduino Software Download Page

Download and run the executable file. Agree to the license agreement. On the next screen, make sure the “Install USB driver” box is checked and finish going through the installation.

Arduino Software Installation Wizard


Mac Installation

For the Mac installation, clicking on the link from the download page will download a zip file. Inside the zip file is the application file. You can run Arduino by clicking on this link directly from your downloads folder, or you can move it to your applications folder.

Arduino Software Download for Mac


Using the IDE

Open up the Arduino software. This will be the environment where all of the code will be written. If the interface is too small to read, you can change the scale by going to File>Preferences. You’ll have to close and reopen the software for to it to take effect.

Arduino Software Preferences

Arduino Preferences Menu

The icon with the check mark is the “Verify” icon. This icon will check the syntax of the code for any errors. The icon next to it is the “Upload” icon. This checks the syntax and then uploads the code to the board. The three icons to the left are “New,” “Open,” and “Save.” The last icon on the far right will open up the serial monitor, which will be discussed in later posts.

Arduino IDE Icons


Communicating with the Arduino Uno

Next we’re going to verify that your computer can communicate with your Arduino. Connect the USB cable to the Arduino and the computer. You should see an LED light up.

Arduino USB Cable

In the Arduino IDE, we’re going to open up an example to upload to the board. Go to File>Examples>Basics>Blink.

Arduino Blink Example

Then make sure you have the correct board selected by going to Tools>Board>Arduino Uno.

Arduino IDE Board Selection

A COM port needs to be selected in order to send and receive data. Select the port by going to Tools>Port. For the Arduino Uno, the COM port is usually labeled. For Windows, the ports are numbered. For a Mac, the port will have “usbmodem” in the name.

Arduino COM Port Selection for Windows

Arduino COM Port Selection for Mac

If you choose the wrong port, the IDE just won’t do anything. To get out of this, choose the correct port and upload again. You’ll initially get an error. Then just click upload one more time.

Arduino IDE Error Message

On Windows, you can check which port is associated with your Arduino by going to the device manager. Scroll down to ports, unplug your Arduino, and then reconnect it. You should be able to see a new COM port pop up. This is the one that is connected to your Arduino.

Windows Device Manager

The particular example that was uploaded turns Pin 13 on and off, over and over again. The “L” LED is connected to this pin and will blink if everything was done properly.

Arduino Uno Pin 13 LED

Now that you’re able to upload to your board, you’re all set to start building circuits and writing code.




Remote Control of a Brushed DC Motor

By Brandon Tsuge,


Introduction

In this post, we’ll learn how to assemble a brushed DC motor with a rotary encoder that is controlled by a radio transmitter. 

Here are the parts I used for this demonstration:

Pololu 50:1 Brushed DC Gear Motor (https://www.pololu.com/product/4753)

I’m not and affiliate for Pololu, but I still recommend this, as it is a quality motor with thorough documentation).

Arduino Nano: https://amzn.to/37z5OJE 

USB Cable for Nano: https://amzn.to/39MXSqW

DROK Dual DC Motor Driver: https://amzn.to/36LDx3y

Radiolink RC Transmitter and Receiver: https://amzn.to/3qvZsU6

Breadboard: https://amzn.to/3ge63xH

Jumper Wires: https://amzn.to/3owv6Pz

AA Battery Holder: https://amzn.to/36N3M9M

Glass Fuse Holder: https://amzn.to/37Fea2w 

Glass Fuses: https://amzn.to/37CUvQP

A typical brushed, direct current (DC) motor has two leads. When a voltage is applied across these two leads, the motor shaft spins. Reversing the polarity of this voltage will reverse the direction of rotation of the motor shaft. DC motors are usually wired to a motor driver, which receive and interpret control signals to ultimately drive the motor’s speed and direction. Brushed motors like this are considered to be open loop, meaning they aren’t capable of sending back information about its shaft position or speed.

Brushed DC Motor

This type of motor becomes closed loop when a rotary motor is attached. In this case, the motor is driven in the same way as any other brushed motor. The only difference is that there is now the ability to measure the motor shaft position. Usually this type of motor will have 5 or 6 wires. 

Brushed DC Gear Motor with Rotary Encoder

Two of the wires are used for the motor power and the other wires are used for the encoder. Essentially the encoder works by turning a signal on and off as the motor shaft rotates. These pulses are directly related to the motor shaft position. I like to use the analogy of a playing card flapping in the spokes of a bicycle wheel. The faster the wheel moves, the more times you hear the playing card making a noise. In the case of a rotary encoder, a high number of pulses over a given time period indicates a faster motors speed.

For this example I will be using a Pololu DC brushed motor with a 50:1 gear ratio and a rotary encoder with two outputs. It has red and green wires to power the motor shaft movement. It has a green wire for a ground for the encoder, a blue wire (Vcc) to receive a positive voltage between 3.5V and 20V, and a yellow and white wire to output separate encoder signals.

Rotary Encoder Wiring




Below is what the output signals would look like as the motor rotates. Notice how they are out of phase. The signals alternate between values of the supplied Vcc and 0V throughout the motor rotation. For this encoder, if you count the rising and falling edges of a single output, you will count 32 counts per revolution. If you count rising and falling edges for both outputs, you will count 64 counts per revolution. Since this is a 50:1 geared motor, a single rotation of the output shaft will result in a total of 3200 counts (50 x 64 counts).

Rotary Encoder Output — Forward direction

The order in which the rising edge of a particular signal is read is an indication of direction. For instance, let’s say that when the motor is rotating clockwise, the rising edge of Output B is counted before the rising edge of Output A. If that was reversed, the rising edge of Output A is counted first, indicating that the motor is rotating counterclockwise.

Rotary Encoder Output — Reversed Direction

An Arduino Nano is being used to power the motor encoder and read the output values of the encoder. It is also sending signals to a dual motor driver to control the speed of the motor.

I’m also using an RC transmitter and receiver to send signals to the Arduino. Essentially, moving a stick on the controller transmits a signal to the RC receiver. The receiver sends a signal to the Arduino which interprets it and sends it to the motor driver. The motor driver receives the signal from the Arduino, interprets it and outputs power to the motor. All of these signals are pulse width modulated signals, which I will discuss in another post. Lastly, as the motor rotates, the Arduino reads the encoder values.

Hardware for Remote Control of a Motor


Wiring

To start this example, I place an Arduino Nano in a breadboard. I use wire jumpers to make connections to the components. The red and black wires on the motor are wired to one of the black sets of screw terminal blocks on the motor controller. The green wire is connected the Arduino ground and the Blue wire is connected to the Arduino 5V output. The yellow and white wires are attached to pins 2 and 3 on the Arduino.

Electronic Assembly of Nano and Motor-Encoder

For the motor driver, the tan screw terminal blocks receive power from an external power source between 6.5V and 27V. I’m using a AA battery holder and a set of 8 AA batteries for this example. The user manual for this board recommends putting a 10A fuse in between one of the leads of the motors and the motor driver and a 15A fuse between the positive end of the power source and the motor driver.

The motor driver also has a set of male header pins. These pins are what control the behaviors of the attached motors. If you look at these two pins, there are two columns. The left column is for one motor and the right column is for the other. The top pins are connected to 5V from the Arduino and the bottom pins are connected to a ground, also on the Arduino. The pins labeled ENA receive a PWM signal from the Arduino and are directly related to the motor speed. These can be connected to any Arduino pin capable of a PWM output. The pins labeled IN1, IN2, IN3, and IN4 control the direction of the motor. If IN1 has a value of 1 and IN2 has a value of 0, one of the motors will spin forward. If you reverse this configuration, the motor changes direction. This applies to the other motor output with IN3 and IN4. These pins can be connected to any digital pin on the Arduino

Dual Motor Driver Board

Lastly, I used and RC transmitter and receiver to indirectly control the motor speed. I chose to use Channel 3, which is the up and down movement on the left stick. I chose this channel because it is not spring loaded and will not return to the center position. The top pin connects to any digital pin on the Arduino, the middle pin is connected to 5V and the bottom pin is connected to ground.


Radio Control Receiver

Below is the diagram of the breadboard view.

Motor and Receiver System Wiring Diagram


Arduino Code

Setup: In this example I use 6 different digital pins. I set the pin leading from RC receiver to be an Input. The pins leading to the ENA, IN1, and IN2 pins on the motor driver are set to be digital outputs, and the pins connected to the rotary encoder outputs are set to “INPUT_PULLUP.”

I also use the “attachInterrupt” command to interrupt the loop and increment counting functions every time encoder outputs a “CHANGE.” Essentially I am counting the rising and falling edges of each of the encoder outputs. This can only be used with pins 2 and 3 on the Arduino Uno and Nano. If a second motor is needed, one encoder output on each motor will not be used. One encoder output per motor is often enough for most projects.

Loop: I start the loop be reading the RC PWM value using the “pulseIn” command. I write IN1 to “HIGH” and IN2 to “LOW” to establish a motor direction. I then use “if” statements to store the minimum and maximum values that are read from the RC receiver. I use this range to map the current RC PWM value to values between 0 and 255, since this is the range that “analogWrite” uses. This value is then sent to the ENA Pin to ultimately spin the motor.

Lastly, I print the counters.

Functions: I use two functions that simply increment two different variables. These functions are called every time the interrupts are initiated. 

You should now be able to control the speed of the motor with the channel 3 joystick on the remote control. 

Here’s where you can find a copy of my code here.

Motor Control Demo

Also, note that when you open of the serial monitor, the counters are increasing as the motor spins. 

I hope this tutorial was informative.

The parts for this post were sponsored by Mechanical Design 101.


How To Get Started With Robotics At Home

By Brandon Tsuge,

If you’ve ever wanted to get started with DIY robotics, you’ve probably heard the name Arduino thrown around. Arduino is an Italian made, open-source, electronics platform with incredibly user friendly hardware and software. The modular nature of the hardware and the simplicity of the programming environment makes it ideal for beginners while still having the capabilities for more complex projects.

Most of the time when somebody says they are “using an Arduino,” they most likely mean they are using the Arduino Uno or Arduino Nano.


Arduino Nano and Arduino Uno


Arduino Uno

Arduino Nano

In simple terms, the Arduino is a mini computer that can perceive the environment through sensors that measure things like light, sound, temperature, distance, etc. It can then use this information to impart change to the physical environment by sending signals to actuators or other hardware. Actuators consist of things like motors, lights, speakers, LCD screens, and much more. The Arduino performs these actions through instructions received in a program, or sketch. These sketches are sent via a USB cable and created using the Arduino integrated development environment (IDE), which is based on the C programming language.


Arduino Communication Diagram


In a nutshell, here are some of the main features of the Arduino:

· Read an analog signal

· Write an analog signal*

· Read a digital signal

· Write a digital signal

· Provide a 5V or 3.3V source

· Provide a ground (0V)

· Easily communicate with your PC via USB

*Arduino can’t truly create an analog signal. It “fakes” it by using pulse width modulation (PWM). I’ll elaborate on this in a future post.

If you are a complete beginner to programming and electrical circuits, I recommend getting the Arduino starter kit (https://amzn.to/2YWt01o). This set comes with over 100 components and an easy to understand project book that teaches fundamental concepts via sample projects. In the upcoming posts, I will be providing tutorials on each of these examples from this book.