2600 Hertz Single Tone Generator Schematic ------------------------------------------- Parts: 555 timer I.C. 8 ohm speaker | 9 volt battery & connector --+-- = connection Pushbutton switch | 5k potentiometer 1k ohm resistor | 4.7 micro-farad capacitor ----- = no connection 3.3 micro-farad capacitor | +----+-------------------------------+ | | | | V 1k | | /\/\/-+-/\/\/-+---------------+ | +--------+ 5k | | | | | ---|--------|-------|--------|--- | | pshbtn | o | 8 7 6 5 | | | switch -+ | | | | | o ||| 5 5 5 | | | | ||| TIMER | | | | | | | | (+)-----+ | 1 2 3 4 | | | 9 volts ---|--------|-------|--------|--- | | (-)--------------+ | | | | | | +-----------------------+ | | 3.3uF | | | +--->|--------------------+----------+ | | 4.7uF \_/ | --- | |(+) | | ______ | +----| 8ohm |----+ /__SPKR__\ To calibrate: Play next to a pure 2600hz source and adjust the 5k potentiometer until the two sounds are the same. As you get closer you will hear a beat tone form and get slower and slower. When it stops, the two frequencies are equal. This takes a little practice.