Braking Activated Rear Bike Light

About: It'd be safer not to

I got bored and decided to liberate my old dynamo light,
so I gutted it, and wired the bulb to 3 AAA batteries and lead 2 leads out the side of the light casing,

I then ran the wires to either side of the disc caliper, for the arm that WOULDN'T be moving i used a bit of metal which the cable tensioner... tensioned and on the arm that moved i just taped some tin foil to the end (same for end of other arm also)

and veola! a craply made light (does work and is kind of rain proof as havn't had any problems yet)

slight warning, if you do attempt this i had to make little washers out of the tape as i didnt have rubber ones, as it makes the whole brake live

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Be the First to Share


    • Made with Math Contest

      Made with Math Contest
    • Cardboard Speed Challenge

      Cardboard Speed Challenge
    • Multi-Discipline Contest

      Multi-Discipline Contest

    5 Discussions


    3 years ago

    Excellent sir. Well done. I have been trying to do similar with hydraulic brakes where there is no useful physical movement accessible at the brake from which to derive the switching. I have scoured the net looking for suitable sub-miniature hydraulic pressure switch to no avail. All far too big. I am waiting for inspiration. In the meantime I have no stop-light. There are tiny cheap accelerometer chips available to trigger the light so this is what I am looking at now.


    6 years ago on Introduction

    how does it activate when i hit brake ? can you please put more images or source or email me at uzzytech@ i really love this one!!!