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Skipping lightly past my partially successful LED experiment, we are now at PWM control of a motor. Stepping a motor down a 3-speed staircase, 5s per step
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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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