From top to bottom: top view with electronics, front view, internal PCB showing main computer and LED driver, part of the Arduino C++ code

Walk Sign Clock Project

  • Planning

    • I got ahold of a surplus walk sign for traffic intersections with the intention of making an electronics project

    • I realized that it had exactly what was needed for a clock:

      • Displays for hour and minute in the 2 seven-segment displays

      • 1 binary output for AM/PM in the orange hand/white walking man

    • It turns out the electronics inside were much more complex than anticipated

  • Process

    • With next to no documentation for walk sign electronics online, I began looking up what each chip on the circuit board did individually

    • I found the main computer and LED driver chip's data sheets online

    • Cutting the traces leading between the two chips and carefully soldering on my own wires let me spoof the signals and pass data strait to the LED driver chip one bit at a time

    • An Arduino (after a voltage step down) can provide the signal and timing needed to take control of the LED driver

    • Added other components including: real time clock module, Bluetooth, 120V relays, and ground fault protection

  • Results

    • One of a kind walk sign that can accurately tell time

    • Android app to control it over Bluetooth

    • Learned a lot of coding and electronics along the way

    • Gained a new appreciation for breaking an overwhelming project into practical chunks

Chainsaw Longboard

  • Planning

    • My friend and I were looking into electric longboards and considering building one

    • Every component of an electric longboard is expensive, especially if the power train is powerful enough for fun riding

    • Electric would blow our $200 budget by at least a factor of 3

    • A 2-stroke gasoline engine offers much more horsepower for cheap

    • Would need custom deck to accommodate large gas engine

  • Result

    • Bought a used chainsaw because they have both a reasonably sized engine and a centrifugal clutch built in

    • Built the custom deck by laminating sheets of wood with lots of wood glue

    • Initial design used a chainsaw chain with the sharp blades ground off

    • The saw gave a boost but was not the ride we had hoped for

  • A lesson learned and an upgrade

    • Based on what others had posted online, we had a 1:1 saw to wheel gear ratio

    • 3:1 is ideal. Lesson: do your own math, just because someone else did it one way does not make it the best way

    • MIG welded new sprocket assembly onto clutch housing

    • Board can travel 30 mph on flat ground

    • It is fast enough that we rarely keep it on full throttle