2 engine rpm compare

How do you want the difference in RPM to be represented or displayed?

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Are you familiar with PIC microcontrollers?
This was a project from years ago.
If you like either sync indicator, I might dig out all of the files.
Sync indicator for a 31' Bertram with 2 Yanmar diesel engines.
Led light bar and rotating propeller gauge.
Using a PIC microcontroller, counting pulses from the ring gear.
I also had a dual digital tachometer but that wasn’t the objective.

I found this circuit on a previous thread, but need a little help in indentifying the IC pin numbers for the 4029 and 4013 designations on the circuit (e.g. 4029 - PL CP B/D etc to pin # ???. ckt diagram attached

The 4000 series chips were logic devices from the early days see here.
They are available at most suppliers and datasheets are readily available.
For example the cd4029 datasheet is available here.

Mike.
Edit, just realised I added CD which is the normal designation for these chips.

can you indentify which pin numbers are PL, CP and CE in the ckt I attached?

PL = preset enable (or Preset Load) - that means the value of the counter can have a preset value according to the binary value of the four inputs.

CP is clock pulse, the input signal that makes the 4-bit output pins count (up or down).

B/D allows the output to count 0-15 (16 values) B= binary or 0-9 (10values) D= "decimal"

CE is "chip enable". The chip is sleeping/disabled if not enabled.

All the chips are rather connected to ground (0V (low) or supply voltage (Vdd) "hi" which can be 3 to 18v).

Here is the pin values for the CD2029. The datasheet has the pin numbering - don't confuse the input numbers with the PIN numbers.