33+ Dtmf 8870 Circuit Diagram Images. (switch on auxiliary switch s2 only if keys a, b, c, and d are to be used.) now push key '*' to generate dtmf tone. Push any decimal key from the telephone keypad.

Dtmf Based Home Automation System Using Microcontroller from www.electronicshub.org

When it hears a valid tone pair it starts counting binary & showing by the 4 bits.by this 4 bits its giving input to the micro & detecting what inputs have come.so it can determine which output to be turn on or off. Use the above circuit diagram and build the circuit.you can. Dtmf mt8870 audio decoder module.

Here we are controlling an electrical bulb using this circuit project but it can also control many electrical devices with some modifications using 4×16 decoder ic.

When it hears a valid tone pair it starts counting binary & showing by the 4 bits.by this 4 bits its giving input to the micro & detecting what inputs have come.so it can determine which output to be turn on or off. Pisti yo2yln has pointed out that the 8870 has a latched output that holds the last code. When new tone is detected, another set of output will be high. To test the dtmf ic 8870/kt3170, proceed as follows: