Computer Light For Nighttime Riding I use a Wahoo RFLKT+ computer. It has a built in backlight for night riding, but to conserve the battery the light times out after a while (30 second default). Since I have a hub generator, I'd like the light on continuously when riding at night.

During the day the display is reflective, so I'm thinking that an LED shining on the display might be able to light it.

I'm wondering if anybody has done something similar and has suggestions for wiring and placement of the LED. The wiring seems like it would simply require adding an LED in parallel to the headlight/taillight with a currently limiting resistor, I'm not sure sure about how to effectively place the LED.
Some time ago I built something like this myself, in more or less the same way you describe.


  The wiring seems like it would simply require adding an LED in
  parallel to the headlight/taillight with a currently limiting
  resistor.


Exactly. I bought an LED rated for 6V DC by the manufacturer (I think they have a built-in resistor), so I could skip the external resistor. Adding an external resistor should work too, but means more work and more connections that may fail.


  I'm not sure sure about how to effectively place the LED.


Yes, that's the tricky part. I obtained a thin plastic tube (about 1mm diameter), and bent it to form a sort of archway above the computer.

I threaded a flexible wire (naked wire used for fastening, not electrical wire) through the tube. This wire provided stability to the arch, and its ends were wrapped around the handlebar left and right of the computer, to fix the "archway" in place. I cut a small hole in the side of the plastic tube, and threaded the two electrical cables into the tube, one from each sides, so they came out at the hole. Then I soldered the LED to the two cables. Finally I gently pushed the legs of the LED into the hole (one to go left, one right, following their respective cable), so the LED sat in the hole. I finally fixed the arch to the handle bar using the wire ends.

The result looked like this:

   ______________
  / ____     ____ \
 / /     |_|     \ \
 ||      / \     | |
 ||              | |
 ||              | |
 ||  |Computer|  | |
######################
      handle bar
######################


I omitted the the wire and cables due to ASCII art limitations :-).

This worked reasonably well. Electrically, it was fine, but mechanically the setup is rather wobbly, and the wire can break if you bend it too often. Also, getting the angle of the LED right is tricky, because LEDs have a fairly narrow beam.

Still, if you want to give it a shot, it's worth a try. It was not very hard to do, and did not require expensive material (the LED cost less than 1 Euro).