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Topic: Two-way radio SELCAL interface (Read 2244 times) previous topic - next topic


Hi Guys

I'm new here, so if anything I say needs clarification please ask and if my project is really not one for this platform please feel free to say so.

I want to use an Arduino to achieve the following two tasks:

1. Upon a Pin Hi or Lo, send a SELCAL (a sequence of 5 or so audio signalling tones) via a two way radio. The radio has an interface for keying the PTT (5V line to ground) and analog AF in (peak 150mV/600 ohm).

Ultimately I'd like to develop the input trigger to also include detecting keywords from an RS232 printer string and the output to be pre-recorded voice sample (with different samples depending on the trigger).

2. To decode a received SELCAL fed in from the audio output of the radio (peak 150mV/600 ohm) and activate pins to trigger external devices (such as autodialler or lights) and display the decoded SELCAL on an LCD.

The SELCAL tones are single frequency and of known and fixed duration.

Any ideas/suggestions...


LM565/567 or CD4046 Tone decoders?

You can play simple audio samples from the Arduino. Limited by storage space. An external serial eeprom would give you a bit more space for this.

The rest is fairly simple and well within the capabilities of the Arduino. You *could* bypass the tone decoders and use the arduino as the tone decoder. I have seen examples of this all around the web, but I have always been more partial to hardware than code since I am not an excellent programmer.

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