What is it?

This small (40mm x 26mm) circuit blinks lights on and off for use in bike turn signals. It connects to your power source, a latching switch, and the lights. When the latching switch is open, the lights don't receive any power. When the switch is closed, the lights turn on and off once per second (2 Hz flashing speed).

This circuit is perfect for the biking enthusiast who wants to light up their bike with not only constant lighting but also flashing lights like turn signals and back lights. I would highly recommend using adhesive-backed LED strips and if necessary, use cable ties or tape to secure them to hard-to-stick-to-surfaces.

It also had mounting stand-offs in the corners to mount into whatever container you would like. Two fit nicely into an Altoids tin and I used adhesive Velcro to stick my circuits into it without drilling any holes.

Please note, one circuit only powers one signal so if you want left and right turn signals, you need to purchase two of them.

Why did you make it?

I made this as part of a project with my brother who bikes to work every day and wanted to be seen biking home in the winter months when he bikes home in the dark. He not only wanted always-on lights but also turn signals on the sides of the bike and helmet to alert cars. I made this as small enough to fit two into an Altoids tin and run the wiring into there to protect it from the elements.

He loved the outcome and now bikes around safely with his lights and turn signals.

What makes it special?

When looking around for DIY bike lighting solutions, I was unable to find any provided circuits, diagrams, or materials for turn signals anywhere. I made this and figured other people would like to do the same and so I wanted to offer my solution to anyone interested.

Feel free to ask me any questions on this! If people are interested and like this, I would love to modify it and offer variations and possibly smaller ones.