Large Scale Central

Creating a car to measure distance and speed

On my list of things to do is to create a car to measure distance and speed similar to what Bruce Chandler did years ago. I am thinking of using the wireless bycycle version

My question has to do with the the sensor for the wheel. Clearly the magnet must be much smaller as Bruce indicated, My concern has to do with the size of the wheel sensor.

Has anyone tried a wireless version and if so how did you install the wheel sensor.



1 Like

You may want to take a look at this first.


My major intent is distance measuring and GPS does not have the accuracy needed


I built one a few years ago using a wired bike speedometer. I’ll dig it out tomorrow and takes some pics. I used a small rare earth magnet on a wheel. The sensor fit on the truck without issue.

When I did mine, I completely cut off the sensor and just replaced it with a regular reed switch. A lot easier to mount and get a magnetic field around without the huge plastic housing.

Magnet on the back of the wheel, sensor on the bolster. Ran the wire up into the car body. Resoldered the wire back up and was done.

I think Craig has the best answer. If you have a reed switch from a Phoenix board, that should work.

My car is a multi-purpose car; A light and camera platform plus the speedometer…

I was able to use the original sensor because I had a free coupler tang. When I converted these cars to body mount, I just removed the coupler and swung the truck around. That tang prove useful to mount the sensor…