Frequency doubler - low frequency- square wave

ian field

Joined Oct 27, 2012
Frequency doubler - low frequency- square wave

I am using a hall effect device to measure the speed of an enclosed shaft.
The output is fed to a cheap pulse counter that can be configured to display pulses per sec or pulses per min.

The speed of the shaft varies. The normal range is from 5 rotations per sec to a max of 250 rotations per sec.

The problem is that the pulse counter is neither stable or accurate below 10 pulses per second.

The easiest solution is to the double the input frequency.
The counter has x1 , x2 and x10 multiplier for the display.

The doubled the input frequency is easily corrected at the display.

I am hoping some one can direct me to a circuit that can perform the frequency doubling function I require.

Thank you
do what WBahn said - or there's a few electronic methods, one of them uses an XOR gate but I don't remember the details.