How to get speed data from a car??


I try to get speed data from a vehicle(Hunday Accent) by using Arduino UNO and Seeed CAN-BUS Shield. I get some data but i dont know how to get speed information by using them. I have attached a pic showing what i get. Anybody tell me please what all those numbers mean and how can i convert them into speed information…

Thanks in advance :slight_smile:

P.S. I have attached the library i used, as well. (25.1 KB)

I would reccomend looking at this: Tapping into can bus | Hyundai Forums


  1. You need a "scope" (The shield might already do that, if you can steadily get data that actually means something. Basically, a scope syncs the clock and logs the input.)
  2. Look in the Hyundai ETM Manual for info

Most vehicles have a simple pulse system so check the back of the gearbox/transmission for a what looks like it might be a rotary sender unit. It will be close to where the tail-shaft connects to the gearbox.

My Jeep has two wires going to a reed-switch sensing a magnet on the output shaft. Counting those pulses per second will give you road speed as it is after the gearbox.