This was a small little project I worked on in the summer of 2016. While taking my first circuits class, I wanted to experiment with placing some LEDs on my bike. During this time the weatherproof WS2812 addressable RGB LED strips hit the Sparkfun store and I wanted to place a meter strip on my bike!
Like I said, this was while I was taking EE201: Electric Circuits, so my knowledge of designing circuits was minimal. Thankfully there’s this beautiful thing called the internet, so whatever I didn’t yet learn from the classroom could be discovered by a quick Google search.
The overall design of the circuit was fairly minimal. A Sparkfun Pro Micro, which is a ATmega32U4 placed on a breakout board with a USB programmer, was used to control the LED strip. A Sparkfun Power Cell board was used to both charge the Lithium Polymer battery and step up the 3.7 V output to the 5 V needed to power the board and LEDs. The biggest problem with using the Power Cell was that the DC-DC boost converter was limited to 500 mA of current draw, which was about half of the current needed for the meter of LEDs to display peak brightness. Besides these two boards, a capacitor was added as a voltage buffer for the output from the DC-DC converter. A switch was also added to turn the output on or off from the converter. A resistor was also added to the signal line for the LED strips. The components were then soldered to a prototype board that was way to big for what I needed. I was still a soldering greenhorn at the time and did a slightly less than mediocre job at soldering the board together. You can see my work below.
The majority of the project was spent debugging my solder job. I ended up having to learn how to use a spring loaded solder vacuum to clean some of the traces, as a short was the cause of most of my problems. Once the soldering was finished. Code was uploaded to the Micro and I had a pretty rad looking bike. The final product can be seen below.