Reading pulse from a ground

I have run into a bit of a problem in my project. I have constant +12 volts from a connector and another connector that pulses ground at about 1 Hz.

So I need to read pulse count between those connectors. I know I can do this with relay but I want this project to be silent so I was wondering what is the best way of doing this when my counter takes in 5 volts and 20 mA.

Regulator, pnp transistor, etc?

Thanks in adcance and sorry for spelling mistakes, english isnt my first language.

Jookoo said:

I have run into a bit of a problem in my project. I have constant +12 volts from a connector and another connector that pulses ground at about 1 Hz.

So I need to read pulse count between those connectors. I know I can do this with relay but I want this project to be silent so I was wondering what is the best way of doing this when my counter takes in 5 volts and 20 mA.

Regulator, pnp transistor, etc?

Thanks in adcance and sorry for spelling mistakes, english isnt my first language.

Click to expand...

It will be helpful if you can show your circuit. Your explanation is not clear to me to offer any advice.

Here is the schematic for my circuit.



Pulse pin takes 5v and 20 mA.

Im not sure how the pulsing ground pin is made so that is my speculation. I need to count pulses between pin 1 and pin 2

From your circuit, a simple voltage divider between pin 1 and ground could solve the high voltage issue.

Is pin 2, an output or input?

I think you mean pin 2 of the connector, in this case it is an output terminal.
And the MCU pin 13 is the pulse pin, set as input (high impedance)... right?

Should you use the 12V of the connector instead of the 5V of the MCU, in case you will find out that pin 2 is an open collector?

KerimF said:

From your circuit, a simple voltage divider between pin 1 and ground could solve the high voltage issue.

Is pin 2, an output or input?

I think you mean pin 2 of the connector, in this case it is an output terminal.
And the MCU pin 13 is the pulse pin, set as input (high impedance)... right?

Should you use the 12V of the connector instead of the 5V of the MCU, in case you will find out that pin 2 is an open collector?

Click to expand...

The problem I can see is not in the pulse measuring circuit but How your +12 VDC power supply is connected to ground, or how this ground .line is interrupted.
You hAve a 12 VDC source with +12 VC to one connector, and its ground line , "0"v connected to ground, or not? If you connect the return to ground interrupted, then you must generate the +5VDC against GND by a 5 V ZEner diode via a 1 kOhm resistor, so the +5V, 20 mA input receives the required input voltage.

In my opinion you are lost in the input power supply schematic. Please offer the complete circuit, otherwise you are still lost.