i'm going to take a weak signal amplify it then calculate the frequency on an analog pin...
accuracy is kinda important eg...
if a 30hz frequency.... 60hz so if it shows 28-32hz each frequency represents a different user/id... simple as possible as i intend on using an attiny85 as the signal generator...
ill use an uno to program on first.. im worried about using code not designed for the attiny ... thanks 
60 herts - person 1
100 herts - person 2
150… etc etc as long as the tolerance is a few above or below not a problem…
Configure one timer as a counter for the pulse and another as time base.
writing the code to send the pulse and interval, is straight forward enough (delay/digitalWrite,delay or led blink without delay, lot's of options...)...
but, has anyone seen any code to measure frequency? i'll adapt it if so thanks...
but, has anyone seen any code to measure frequency? i'll adapt it if so
There is a FrequencyCounter library. Google will be hearing from you soon, I'll bet.
indeed they will ty