rexlan
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555 tachometer circuit
I have an electronic tach on my small race car. I changed engines and now need to control an intake motor based on engine RPM.
I have a 12v square wave output from the engine ECU that goes to an existing tachometer. I can connect to that line. I have a 4 cylinder engine so I assume 4 pulses/rev.
I need a very, very simple circuit (preferalby a 555 or something even easier, that can count the pulses to figure out the RPM and then at about 3,000 RPM give me a switched 12v output (very low current required).
I also need to be able to program or set the exact RPM to switch at ~ 2500-3500
So if the RPM is > 3,000 turn the little motor on.
RPM < 3,000 RPM turn the motor off.
I have very basic stuff, R, C and a few diodes, FET's. I need a schematic please.
I also have to make this thing very small and I can not use a microcontroller because I need to do this myself.
Thanks for reading and any help!
I have an electronic tach on my small race car. I changed engines and now need to control an intake motor based on engine RPM.
I have a 12v square wave output from the engine ECU that goes to an existing tachometer. I can connect to that line. I have a 4 cylinder engine so I assume 4 pulses/rev.
I need a very, very simple circuit (preferalby a 555 or something even easier, that can count the pulses to figure out the RPM and then at about 3,000 RPM give me a switched 12v output (very low current required).
I also need to be able to program or set the exact RPM to switch at ~ 2500-3500
So if the RPM is > 3,000 turn the little motor on.
RPM < 3,000 RPM turn the motor off.
I have very basic stuff, R, C and a few diodes, FET's. I need a schematic please.
I also have to make this thing very small and I can not use a microcontroller because I need to do this myself.
Thanks for reading and any help!