Hey all, this is my first post! YAY! I am trying to make a tach that i can read the cars RPM's. I am only looking for the chip to see what the RPM's are and not display it out to the user. I've draw up how i think it should be hooked up but I'm still now 100% sure. On the PDF it has 15v being used for the VCC, however i will be using 5v so i need to figure out how to change the resistors and such to accommodate this change.
I will be using the LM2907 chip and tapping into the tach wire from the ECU of the car. I'm looking at it as if the RPM's are 50+ then the car is started. Anything lower then the car must be off. I'm checking because i will be remote starting the car and need to know when the stop cranking it.
http://www.national.com/ds/LM/LM2907.pdf (Page 8)
Any help would be great!
David
I will be using the LM2907 chip and tapping into the tach wire from the ECU of the car. I'm looking at it as if the RPM's are 50+ then the car is started. Anything lower then the car must be off. I'm checking because i will be remote starting the car and need to know when the stop cranking it.
http://www.national.com/ds/LM/LM2907.pdf (Page 8)
Any help would be great!
David
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