Backpack Brake Light and Turn Signal
Estudio Roble’s backpack-mounted light assembly adds bright signaling capabilities to bikes.
When riding a bicycle, sharing the road with vehicles and even pedestrians can be a challenge. It seems that everyone has their own unwritten rules, plus assumptions about what you’re going to do since you don’t have brake/turn signal lighting. While it won’t solve every bicycle safety issue, Estudio Roble’s backpack-attached device enables you to display turn signals, a brake light, and a blue default/moving light to increase your visibility.
The project is outlined here, as well as in the video below, and features an impressive array of NeoPixels for visibility, plus an Adafruit Circuit Playground Express (CPX) for control. The main lighting consists of four strips of 17 NeoPixels arranged in a vertex-oriented square pattern, along with 10 additional NeoPixels built into the CPX itself.
This setup should get the attention of any nearby car. It also allows for very obvious turn signaling, using two of the strips, plus a half of the CPX NeoPixels.
The unit leverages the CPX’s onboard accelerometer, sensing braking automatically. A Kalman filter is used to even out bumps; however, it needs to be adjusted correctly so that it’s not continuously triggering.
A handlebar mounted RF transmitter is used to switch on the turn signals via user input. Build files are available on the project writeup, or you can buy it as a kit on Tindie. You’ll need to supply your own power bank either way, and as a reference point, a 20,000 mAh pack lets it run for over five hours.