Devlog #7: Pin-Pinching Hacks, Mechanical Chaos, and Big Life Updates

– From Sep 21st to Sep 26th 2026 –

This past week has been an absolute blur of hardware troubleshooting, unexpected setbacks, physical injuries, and huge personal milestones.

After sending Jay@Stardance a video proving the Arduino Mega was officially toast (RIP), I jumped straight into assembling the cooling setup with the TEC1-12706 Peltier module. That thing gets insanely hot within seconds leaving me with a nice second degree burn as a souvenir. Since I still didn’t have a new tip for my soldering iron, I wired up the main rocker switch using good old Egyptian electrician techniques, twisting the bare wires around the pins in a slightly cursed knot, followed by plenty of electrical tape and heat shrink tubing.

With hardware up in the air, I spent considerable time optimizing circuit logic to minimize GPIO pins so the entire project could run on a single Arduino Uno if replacement funding fell through. Bypassing the microcontroller for components that stay on continuously (like the relay) saved digital pins immediately. By tying all eight HC-SR04 ultrasonic sensor TRIG pins into a single line, the total GPIO requirement dropped down to just 13 pins, 1 shared TRIG pin + 8 individual ECHO pins 4 directional control pins for the L298N motor driver

On the physical build side, I finished the insulated fridge compartment, mounted access doors, installed locking latches, and laid out the lower drive chassis. Hot glue turned out to be useless against motor torque, and the heavy lithium battery pack caused the chassis to drag, so I installed a heavy duty caster wheel underneath the frame to balance the weight.

Then came the hardware headaches. The cheap 12V cooling fans turned out to be completely dead on arrival (details in the journal.md). Instead of dealing with local return hassles, I mounted them decoratively for display while keeping the working Peltier module unpowered to prevent further burns.

Mid-week brought an incredible thing: I got accepted into the Faculty of Science at Cairo University! 🥳 With the Stardance deadline extended to October 31st, I took a brief breather to celebrate followed by a quick internet outage that paused video logs. so I took 2 days off

Getting back to assembly, initial power tests revealed the DC motors were running way too fast. To tame the speed, I removed the jumpers on the L298N driver to enable PWM speed control, using up the absolute last 2 available GPIO pins on the Uno. I also had to rebalance the wheel alignment to expand the base area. The heavy battery was originally locking up the motors in the bottom tier, so I relocated it up to the middle tier which it’s super crowded now, but cable management kept it clean.

Naturally, I managed to cut my hand on the saw again while trimming wheel clearance, but thankfully it was minor.

With the chassis built and the electronics wired, the rover is practically finished. All that remains is picking up a few extra Female-Male jumper wires to mount the ultrasonic sensors on my way to college today, and EcoRover will officially be ready for initial testing. (I’m too tired to put photos, so here’s red mike wazowski again