Quote:
Originally Posted by coopzone
2 GND wires, one -ve power the other audio ground to the -ve per on the PSU where in connected to the board I made.
1 +ve (9-12volt required) to the PSU +ve direct from the transformer. So the same power supply is used for both the transmitter and the module.
Left+Right audio connected to R1 as Audio input to the transmitter.
Thats it. The module is so simple it does not even come with a connection diagram, it's printed on the PCB!
Derek
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My module has just arrived from a UK seller. Ordered on 30 Sept, was despatched to Courier firm same day, delivery stated as 4 Oct. Actually took till today to arrive. Ironically, I'd ordered something else but from China on 30 Sept, which also arrived today. Not the fault of the supplier. No dramas - not in a hurry for it - I've been furtling with a min-mod meantime, which just needs boxing up.
As Derek said, the unit comes with no instructions, and I'm glad he said: "they're on the PCB" as indeed they are, but underneath the PCB, where initially I never thought to look! One of the connections is for an antenna and if Derek happens to read this, perhaps he can comment on what he did about that. With the Carl Fernando FM/AM converter design which uses the RDA5807RDM module, it just uses 15" of wire for both the FM & AM antennas.
Based on helpful feedback in this thread from forum members about the PCB layout I'd designed for the unit, I've updated the layout to incorporate the suggestions, and have attached the updated layout and PCB masks. However, I've not yet built it so I'm not suggesting that anyone uses the circuit or layout - I've just attached it for interest. Basically, it just uses the digital FM module in place of the RDA5807 FM module and Guy's programmed PIC, 'bolted on' to Guy's MW AM modulator circuit, which is tried and tested and works well.
However, whereas Guy's design runs off 2 x AA cells, this is mains powered via a 9V 'wall wart', hence the 100uF smoothing cap on the power supply input, with a100nF parallel cap. I've incorporated a diode to safeguard against inadvertent reverse polarity, but haven't added a Voltage regulator as I don't think the supply voltage is that critical, but I notice that the PCB power input does state '5V' whereas Derek says '9 - 12V required'. (The unit I have looks identical to his). That said, it has what looks live a 5V regulator on board marked '78M05.
I hope this update is of interest.