Audio Transmission

[EmilyJane]

@english_fellow

voltage output from a microphone is tiny and I’m still trying to learn how to connect/bypass it.

Similar applications with ham radios feed the attenuated signal into the mic input after it has been attenuated. I'd try dividing your audio signal down to a low level with a potentiometer.

[EmilyJane]

@srnet

which device category ?

PMR446. Analogous to the US FRS radios.

[runaway_pancake]

@english_fellow

currently lacking the knowledge to interface the audio output from arduino into the microphone circuit.

You could try "audio coupling" - put the speaker up to the microphone, adjust the speaker volume as necessary.

[Paul_KD7HB]

@english_fellow

one could tune to a specific frequency on a standard transceiver and get the data through audio.

Actually, all the type of transceivers you are thinking about have a fixed number of defined frequencies and you will have to accept any interference you find on your choice of frequency.

[english_fellow]

@EmilyJane

Similar applications with ham radios feed the attenuated signal into the mic input after it has been attenuated. I'd try dividing your audio signal down to a low level with a potentiometer.

Roger that, looking into it, appreciated!

[english_fellow]

@runaway_pancake

You could try "audio coupling" - put the speaker up to the microphone, adjust the speaker volume as necessary.

Thanks,
Do you meanconnect the speaker out connection to the mic in connection? Or physically put the speaker next to the microphone?

[english_fellow]

@Paul_KD7HB

Actually, all the type of transceivers you are thinking about have a fixed number of defined frequencies and you will have to accept any interference you find on your choice of frequency.

Maybe I worded that incorrectly. What I meant was transmit on a frequency that the transceiver can pick up. Have the transmission frequency adjustable depending on the area/frequencies in use/legality.

[EmilyJane]

FYI, a handheld radio might need an input of around 20 mV peak to peak at the mic input so be aware.

You can also normally use a logic level MOSFET to switch the push to talk of your radio rather than a relay.

[Paul_KD7HB]

@english_fellow

Have the transmission frequency adjustable depending on the area/frequencies in use/legality.

Please do some research relating to your own area. All the potential devices/frequencies in the US that are license-free specifically prohibit data transmission, which is what you are asking about.

[EmilyJane]

@Paul_KD7HB

potential devices/frequencies in the US

It turns out that @english_fellow is in the UK. Who knew, right?

There is a service there called PMR446 that is roughly equivalent to the US FRS/GMRS. It is sort of compatible with its European counterpart with the notable exception that they allow digital as well as analog transmission. What I don't know is if they allow remote control of a transmitter and @english_fellow will have to determine that if they want to be strictly legal.

[english_fellow]

@EmilyJane

FYI, a handheld radio might need an input of around 20 mV peak to peak at the mic input so be aware.

You can also normally use a logic level MOSFET to switch the push to talk of your radio rather than a relay.

Thanks again, and its possible to connect the audio out to the mic in directly if I divide the audio signal down to below the mic input? Would that give the same signal as speaking into the microphone?

Will for sure use a MOSFET as the switch eventually.

[EmilyJane]

@english_fellow

possible to connect the audio out to the mic in directly if I divide the audio signal down to below the mic input? Would that give the same signal as speaking into the microphone?

Yes, you would capacitively couple the signal as well as attenuating it. Your audio source might have a capacitor on the output already but if not, add one. Depending on the input impedance of the mic input a 1 microfarad cap would be a good choice.

[english_fellow]

Fantastic, thanks again for the advie =]