Sunday, August 4, 2013

Bike Suite Part 1

A couple of weeks ago I wrote about the deaths and hit and runs that we have had here in Pittsburgh. I titled that article "A bit Upsetting" when the truth of the matter was that I found the whole thing very upsetting. I felt so helpless that people were being killed and people I knew and thought of as friends were ending up in the hospital. I had to do something, but the truth was I had no idea what to do.

Until I looked at my work area.

That is when the idea that has absorbed my mind for the last month. The idea of a set of electronics that I could build that would do two things. First it would increase the visibility of cyclist to the motorist. Second it would help the cyclist be informed of the surroundings. (I am thinking here of cars to the rear and left of the cyclist.) So I have thought long and hard about this, waking up in the middle of the night and finding it hard to fall back asleep as my mind pondered over some little detail.

Losing sleep makes me crabby.

So what follows may be a little geeky for some of my Cycling friends but I am hoping that you can help me see the things I am missing.  First lets start off with a general description of what this Bike Suite will do.

The bike suite will accomplish several goals.

Object Detection Mode
1. Detect Cars that are closer than the 4 feet (1.22 meters) allowed by PA Law.
2. Detect Cars before they are beside the bike. at 45 degrees behind bike
     (i.e give cyclist time to react)
3. Flash lights to alert Motorist that they are too close.
4. Warn cyclist with lights that object (Car) is to left rear.
5. Warn cyclist with buzzer when object is within 30 inches (0.76 meter)

Brake Detection Mode
1. Detect when bike is slowing down
2. Flash taillights to warn people behind (motorists and cyclists) that bike is slowing down.

Standard Rear Light Mode
1. flash rear lights as standard rear lights

Hacked Tail Lights
I started with the cheapest tail lights I could find at my local bike shop. I then opened them up and I hoped that I could use the hardware inside the tail light but that wasn't meant to be. So I tore out all the innards and whipped up the new hacked innards.

I plan on using hot glue to seal up where the wire goes, and locate the board inside the two tail lights.
These lights will be the main way to communicate to the motorist. Below is a video of the hacked lights blinking. Try not to be distracted by the sound in the background

This should give all of you some idea what I am working on.


The whole thing is being controlled by an Arduino Uno (Microcontroller), but the final prototype will be with a much smaller Arduino Micro. Check out the following photo for an idea of scale. The larger one is the Uno.

The idea is to use an Ultrasonic sensor to detect an object behind the bike at 45 Degrees. When something is detected and it is closer than 4 feet the left tail light will flash like it is shown in the video above. A light on the module attached to the handle bars will also flash, thus alerting the motorist and the cyclist. See photo of Ultra-sonic distance sensor below.


Brake detection is accomplished by the use of an accelerometer.  This will detect if the bicycle is speeding up or slowing down. If it detects the bike is slowing down it will flash both tail lights solid. Right now I am in the process of determining how much of a change in acceleration will cause the brake lights to turn on.

At the moment I am trying to build all the modules and get the code working to allow it all to work together. I will keep you informed of my process here. Also when it is finished I will make detailed photos, schematics, and the computer code available as part of the Open Hardware Repository and Creative Commons Projects. Meaning that anyone who wants to can build a system of their own.

If you have any ideas of options or actions that could be added to the Bike Safety Suite please leave them in the comments.


  1. Brilliant. Awesome. Taking initiative. Man, I love everything about this. Plus I want one, please. Really very nice, Terry. I didn't know you did this kind of thing.