My primary transportation is an elBodaBoda electric assist cargo bike from Yuba bikes. It’s a great bike and a real car replacement with cargo and passenger capacity. The electric system comes with a tail light but no head light. It does however include an auxiliary power output that supplies 6V whenever the tail light (and control panel back light) is switched on. So I headed down to my local makerspace and quickly whipped up a headlight.
Electronics
I had some 10mm 85mA white and yellow LEDs laying around from a previous attempt at an ebike headlight project that I never managed to finish. Conveniently, the combined forward voltage of one white and one yellow LED worked out to just over 5V which meant that I wouldn’t need to waste much electricity in the current limiting resistor to drive these from the 6V power. I used to pairs with the yellow pointing 45º to the side.
I also wanted an auxiliary USB power port so I added a 600mA 5V LDO to the bus along with the pigtail to go to the ebike battery.
Case
The case I quickly designed in 3D CAD in three pieces to fit snugly around the board and LEDs and assembled it with hot glue. It isn’t the most elegant thing in the world but it does function. What I am proud of are the curved passthroughs for zip ties to attach the light to the bike. These are a structure that really could not have been made any way other than 3D printing.
Reflector / Shade
After trying the light out for the first time, I realized it was shining up into my eyes much too much because of the wide viewing angle of the LEDs. So I used another makerspace classic, the laser cutter to cut a piece of acrylic mirror scrap into a reflector / shade which directs more of the light down and forward and protects my night vision.
Now I have a custom light that works great and I never have to worry about replacing the batteries.
Conclusion
Along with the elBodaBodas tail light and the head light, I also have Revolights on the rims of my wheels which are amazing, especially for side viability and pedals with integrated generators and lights to keep me visible at all times.
