Im looking for, or how to build a digital speedometer for my rx-7 that will interface with a laptop or car pc. So that I can write a program that will register the speed and the milage, and calculate my ETA based on rate of travel and distance. I Have already visited dakota digital and i think that i could use there stuff like th sensor kit and the controll box but i need to make that interface with a pc and perferably a paralell, or usb port. thanks
The FC (assuming this is a 2nd gen?) has a VSS sensor that is for the cruise control. You get a pulsewidth based on the speed of the vehicle. This is documented in the factory service manual. All you would need to do is read the frequency of those pulses with a microcontroller and display output based on what you are seeing. If I am not mistaken, it is the factory speedometer that actually generates this signal. If you are converting to an aftermarket speedometer, then it will come with a hall sensor that reads a magnet you place on the driveshaft.
To calculate mileage, you also need to read injector pulsewidth and distance travelled.
digital speedometer with pc interface.
Posted - Aug 07 2005 : 3:01:50 PM
