Ideas needed for GPS/UHF/Car Radio setup

sounds like you need a vox switch to mute the radio.

but do you want a ready-built unit, kit, or a schematic.

try a carphone specialist for the former.

Bye. Jasen

Hi Jason

I am looking for circuits or would consider a kit but ready built is out of the question due to $$$$$

The vox part shouldn't be too hard, but am not sure about how to give the GPS priority over the UHF

cheers

David

jasen wrote:

It could be as simple as a signal detction circuit for both the UHF output and the GPS, feed into two OR gates driving the mute control on the radio (does it have one?). So if the UHF or the GPS gives an output the radio is muted.

Then you probably need a seperate power amp and speaker for the UHF and GPS, it might be too much trouble to swich it through into the radio speakers.

You'll need a line level switch hooked onto the logic to mute UHF signal when the GPS signal comes through.

Dave :)

I was thinking I would feed into the audio section of the radio - maybe at the vol control, and at the same time remove/short the radio signal by way of an OPTO to effect a mute.

Is this essential you think? I was thinking to just disconnect the (speaker) OP of the UHF (ie the OPTO off) when the GPS gave a signal - eg perhaps a PICAXE driving optos as switches to connect the units to the radios audio, and using the interrupt to detect OP from either unit and logic to let the GPS have priority.

Thanks for your reply

David

Sure, plenty of ways to do it. Don't need a PIC-AXE though, just a circuit which detects audio output from the GPS and the UHF. i.e. a high when there is signal, low when there isn't. Should be pretty easy as both of those outputs should have no signal when not active, so the threshold level is easy. The output from the signal detect circuit then drives some TTL logic which then disables the appropriate audio channel by your chosen method.

Dave :)

Toyota mute is the 'empty' plug, next to the white lead of the small plug of the radio (if it has mute in that model)

I have a very novel solution: Turn the radio down to a civilised level so you can hear the GPS and UHF. It works for me, I dont have a UHF, but I have a GPS and 2 mobile phones and occasionally 3 screaming kids.

Thanks for the reply Two Bob

I haven't pulled the radio out yet to check if it has a mute, but will do soon.

Re hearing the units, I think my hearing might be winding down a bit as I have trouble hearing the GPS over road, car, and traffic noise, without the radio playing - 4WD diesels are not the quietest of vehicles, but a new one right now is not an option. The UHF is not too bad, but the Nuvi GPS has a very limited audio o/p

Cheers

David

two bob wrote: