I currently have the phidget 8/8/8 interface kit, and was hoping to use it to get engine rpm from the ignition coil and speed from a hall effect sensor.
After looking around on the internet on ways to get a 0-5V signal out of the pulse that comes from the coil I found the frequency to voltage converter LM2917. The problem is i've never realy done anything on the hardware side except building a circuit that pretty much had step by step instructions.
I found a sample circuit for the tachometer setup at http://www.niksula.cs.hut.fi/~mdobru...cho/tacho.html but it is lacking some information, or I am. The questions I have are probably insanly simple to answer hopefully, and if anyone can help me out id be most gratefull.
- What type capacitor should i be using for this setup? I assume the voltage out of the ignition coil is quite a bit and after looking through digi-key there are so many choices I dont even know where to start.
- Same as above but for the zener diode. What would be suited for this application?
- And hopefully someone can confirm that with that circuit all i should have to do is hook the Vout line to the data pin on an analog input for the phidget, same for ground i assume. But do i need to use the 5 volt line from the phidget interface kit? (probably somthing i should ask on the phidget forum i guess)
Sorry for the pretty long post, but I hope i covered all my issues atm.