timing sensor

[e44-72]

Hello

I want to know if there is a component or circuit that can sense a certain frequency of flashing voltage and if the frequency is increased/decreased it makes cetain outputs turn high/low. The frequency would be coming from the output of 555 timer ic.

thank you for reading and any help.

 

[alec_t]

What frequency range?
How much must the frequency change before the output changes state?
What accuracy of frequency shift detection do you need?

 

[e44-72]

A frequency range of about 1 to 100 hz. The frequency must change about 20 hz for out put to chnge state and accuracy of about + or - 5hz

Thank you for your reply

 

[crutschow]

Do you many any 20Hz change, such a 10Hz to 30Hz or 50Hz to 70Hz, etc.?