RGB Handlebars


  • 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


  • 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


  • 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