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With the advent of fall, it’s sometimes hard to realize that the days have become shorter, although the temperature may be the same. It’s happened to everyone- you go on an afternoon bike trip, but before you’re halfway back, it’s dark and you’re thrown into a game of hide-and-seek with every other vehicle on the road. Why not let the world know which way you’re going turn at the next intersection by building a simple and low-cost turn signal?

This project is for people who need a safer way to bike at night. It’s easy to make, works great, and is the perfect way to learn about basic woodworking, electronics, and programming.

So, if you’d like to get started, read on!


Hacksaw or any other saw
Drill, with 3/16” and 1/16” drill bits
(Optional) Countersink drill bits
Single-use superglue (or similar)
Soldering iron, solder, solder stand
(Good to have) Tabletop clamp. This is something you should invest in if you have space, it makes drilling and cutting a whole lot easier.
Ruler, pencil

Arduino Nano, preferably with a breakout board
Stranded wire, a decent amount (You’ll need 3 wires that are around 2m long)
13x LEDs (orange or yellow, although the colour is up to you). Note that it’s a good idea to get extras in case you burn out a few. Also important to keep in mind- mixing colours means your LEDs will light up at different brightnesses. This is because the internal resistance of an LED is unique to its colour. It’s best to use 13 identical LEDs.
13x 220-ohm resistors, generic. Both these and LEDs are easily found on amazon.
An SPDT toggle switch, ON-OFF-ON. For example, these ones
Other Materials:

Wood panel, around 4”x2” or larger, and at most 1/2” thick. Plywood is a good source.
(Optional) Acrylic plastic, 1/16” or thinner
Zip ties
Screws, relatively small, such as these
Electrical tape
Old rear/front bike reflector, such as this one. What we’re interested in using is the mounting bracket. If you have a mounting bracket from a bell, speedometer, etc. that can also be used.
Some sort of malleable foam. The stuff you wash your dishes with is probably good.”

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