Categories: Electronics, Programming
| Year: 2022
Objectives
- Make cyclist more visible to cars by adding lights on the sides of the bike
- Makes the shape of the bike more defined than if there were only lights on the front and back
- Look cooler than a single color light
- Have a long-lasting battery
Process
- Initial design used an RGB pattern LED in a long tube
- Tube contains two AAA batteries to provide 3V to the LED
- LED diffuser sticks out from handlebars to be more visible
- Latched pushbutton underneath turns the light on/off
- Electronics connected with thin magnet wire
- Second design was more compact and customizable
- Includes nickel-sized PCB with light circuit
- PCB milled at home on CNC machine
- ATTINY 45 microcontroller runs an RGB LED
- Microcontroller programmed in C++ without Arduino framework
- Custom light patterns can be added
- Pushbutton toggles light on/off and changes light pattern
- Powered by two coin cell batteries that together provide ~3V
- Case is 3D printed, with an unscrewable top for accessing the internal circuit
- Includes nickel-sized PCB with light circuit
Reflection
- The first prototype was very reliable
- Used for almost a year before the diffuser broke off
- Second design was more fragile
- If bike is leaned against a wall, the pushbutton is crushed
- Both designs are not bright enough to be seen during the day
- Both designs are clearly visible at night
- A higher power LED might be visible in the daytime, but would also draw more power
- This project improved my skills significantly
- I got better at milling PCBs by adjusting my workflow and finding better cutting tools
- I created the Clothespin PCB Probes in order to program the PCB, and they have been useful for other projects
