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I haz digital inputs. These teeny switches were annoying to insert. I’m working through the Elegoo mega 2560 kit manual, one experiment every morning. Takes about 15-20 minutes. Right now focusing on the mechanical assembly skills, not really tweaking the canned sketches.
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Bought the helping hands too. Between that and the cheapie usb microscope. I’m set as far as vision issues are concerned for now.
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Shit last update was 12/26 which means I had 2 months off the electronics track. I gotta find a way to cycle through electronics sessions more often. At this rate I’ll never get to rover control.
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Didn’t work initially, some of the leds weren’t working. After laboriously testing them, discovered the 74HC595 shift register chip wasn’t seated properly across the gutter (?) of the breadboard. Had to prise it off and reseat. In general the mechanical assembly part is fiddle.
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So far I haven’t tried designing my own circuits or writing code. Just doing the tutorials and editing code samples. Yellow-belt stuff. I need to set myself a series of green-belt to brown-belt exercises pointed generally in the direction of the black-belt projects I want to do.
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Made slight mistake connecting power between 3v and 5v instead of ground and 5v. I’m getting better at diagnosis. Only took a few seconds to look in the right place for the error. Fortunately not a damaging error. There seem to be few irrecoverable errors in basic Arduinoing.
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Need better ergonomics. I get a slight headache every time I do electronics, even with reading glasses and magnifying glass. It’s like 3x the strain of simple laptop or phone use.
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7 segment experiment has all sorts of issues. First time it didn’t work and couldn’t figure it out, so I ripped out and rewired. Second time I had the thing upside down so the pins were all wrong. When I finally wired it right it works but randomly blinks off 10-12s at a time.
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Either I damaged it during the wrong wiring or there’s still an error. The code currently just cycles through the hex digits. Not sure where to begin troubleshooting.
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Grr. Debugging electronics is weird because when things are wrong it either just doesn't work at all, or does random shit. Like the first time I had it wired wrong, digits would randomly light up.
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The second time, weirdly enough it sorta worked even though the pins were upside down. It got some of the digits right, the others not. Now, it works, but the random turning off in the middle of the cycle is the residual bug. Setting it aside for now.
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Hmm the display is just a bunch of leds and I did some segment by segment testing. Seems to be fine. I don’t think the latch chip could have been damaged.
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Possibly something about the clock timing driving it? Why would it blink off for10-12 seconds at a time 🤔
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This is I believe the first time I’ve used a non-led diode and a transistor ever, so achievement unlocked! Arduino sketch was a bit unclear... it would run and stop after a second. But then I added a delay and it ran longer. Does a pwm pin output a default fixed length pulse?
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Anyone know why this sketch would stop after a second? When I added a delay right after the analogWrite, it ran longer I don't see a rewrite-to-0 command on the pin, so I'd think the value would remain high at input level until I put in a different value in serial monitor?
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Control with a 5v relay. This was a bitch to troubleshoot. Just wouldn’t work. Checked and double checked circuit. Coil voltage was switching correctly but load was not switching. Thought I had a fault relay...
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Figured out how to test the relay directly with a power supply and a multimeter... it was working fine. Turned out the pins are just kinda the wrong spacing and length and it just wasn't sitting correctly in the breadboard, and I had to really push it down with my thumb.
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With this, I have officially completed the Elegoo Mega2560 tutorial manual, even though it only introduced me to like half the components in the kit. Haven't used : capacitors, ultrasonic sensor, led panel, motor controller, stepper... gonna have to go hunting for sketches.
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We move into the wild lands beyond the manual by figuring out servo motor control... which lies about 0 and 180 degrees... I’ll have to dig into this mysterious servo.h library.
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Both these were fairly trivial. The hard one was DC motor control with a relay. On to speed and position control in next session.
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Status: I’ve learned to use the following things from the kit. 31 of 54 components. Gonna have to design my own learning experiments for all the others.
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Spent an hour looking up what seem to be really finicky beaglebone blue JST-SH and ZH connectors. Why couldn’t they use more standard ones?
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Trying to use this single-board robotics-specific computer to simplify my life, but realizing there are downsides now. None of these headers are the usual sizes. Anyone used this BBBlue board for a project?
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Setting up for soldering phase of learning curve. Made smol hack with ventilation tube and shoebox so fume extractor pumps solder fumes out instead of recirculating. Air quality got pretty bad the first couple of times so figured this was needed.
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Though my tube is a bit tougher (plastic-coated aluminum), so that’s good. I was going to 3D print an adapter plate to bolt on but the 4 screws aren’t long enough. Future yak shave. PM2.5 *really* blows up around soldering and I’m a bit sensitive so all mitigation helps.
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Continuing my "beyond the kit" adventures, managed to get an L293D H-bridge circuit going to do directional motor control. Unfortunately, the delicate motor leads ripped off while I was playing around and before I could take a video. Now I have a solder-repair job to do.
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Well, it works. Beam is very narrow though. Like 15 degrees maybe? Wonder how closely you can space these guys. Could I put like 6-8 of them around my rover for 360 degree and do SLAM? They can share power and ground but each requires 2 pins. Maybe poll them with a selector bit?
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