[SequoiaHope]

I helped Alex invent that product! I built the first prototype that helped him get funding and hand assembled some of the first PCB designs. My (old) name is on the patent.

I’m glad to see this was already posted. I wear mine when I ride my 1500w ebike around and I feel so much safer with it. It’s really bright too!

[amelius]

That's cool. What principles is it based on and was it difficult to clean up the signals to get a reliable input?

[SequoiaHope]

I did not write the production code but I imagine they are tracking the velocity and acceleration vectors using a kalman filter and lighting up the lights when acceleration is negative in the direction of travel. By tracking the velocity vector in addition to acceleration one can eliminate the effects or the driver turning their head. I.e you are not just looking for a specific accelerometer axis to go negative, you have to use a more complex filter to determine the actual physical direction of travel of the device even as it rotates, and check for negative acceleration in that direction. To learn more:

https://github.com/adafruit/Adafruit_AHRS

https://learn.adafruit.com/how-to-fuse-motion-sensor-data-in...

[haiku2077]

I got one for my birthday! What a great product. It does exactly what it says it does, and has no more complexity than required.

[SequoiaHope]

Yussss I’ve been really impressed that Alex has made such a solid product. He was starting up just as my business failed and I warned him it can be a difficult road, but he stuck with it and has delivered something really special.