Speaker OUT To MIC IN

[elyas721]

I want to use dfplayer modules speaker output to connect to SIM800L MIC IN Pins.Can this being done? How to connect it?
In other words Instead of a MIC input on SIM800L module, I use the sound out of the dfplayer module.
Please see the attached file.

What is the reason for the noise? How can I fix the noise? Can you guide me by schematic?

Thanks

 

[rjenkinsgb]

Connect the ground lead from the DFPlaye module directly to the ground on the SIM800 module, instead of to the PSU.

 

[elyas721]

Connect the ground lead from the DFPlaye module directly to the ground on the SIM800 module, instead of to the PSU.

dfplayer outputHow do I connect to the mic?

 

[elyas721]

Connect the ground lead from the DFPlaye module directly to the ground on the SIM800 module, instead of to the PSU.

I tried with 1k and 10k resistance, but it has no effect

 

[elyas721]

This project has become very boring for me, I even combined the source of Arduino, dfplayer and sim800, but the problem was not solvedDo you know any other solution besides dfplayer that will work?My goal is to save mp3 in sd or usb, the output to the sim800l microphone inputto connect

 

[rjenkinsgb]

You need a perfect, direct ground connection (and no ground "loops") between the two modules, to get good audio.
Having them separately grounded to the PSU can cause noise.

That will apply between any audio source and the SIM800.

Connect the audio module ground, then try the 10K resistors again.

 

[elyas721]

You need a perfect, direct ground connection (and no ground "loops") between the two modules, to get good audio.
Having them separately grounded to the PSU can cause noise.

That will apply between any audio source and the SIM800.

Connect the audio module ground, then try the 10K resistors again.

I connected it like this, did I make a mistake somewhere?There is still a hissing sound

 

[Nigel Goodwin]

Way back in this thread I mentioned you should attenuate MUCH more than you're doing, and you're still feeding line level inputs (barely attenuated) into a mike input. For a start, as I suggested before, replace the 10K with a 470K to get down towards something like a mike input level.

 

[rjenkinsgb]

If the mic input to the SIM800L is a true differential type, equal resistors in both signal lines may work better (eg. 10K in each), plus the 1K across the mic input.

And, add the 47 or 100 Ohm directly across the DFPlayer output?


Nigel - the SIM800L datasheet gives signal-to-noise at a signal level of 0dBM0, so around 600mV should be acceptable, presumably via some built in AGC?

It certainly should not need to be at low millivolt levels.

10:1 should be more than adequate reduction.

 

[elyas721]

Way back in this thread I mentioned you should attenuate MUCH more than you're doing, and you're still feeding line level inputs (barely attenuated) into a mike input. For a start, as I suggested before, replace the 10K with a 470K to get down towards something like a mike input level.

I did this method, tried 470k, the hissing increaseddfplayer music soundNothing is played

 

[elyas721]

If the mic input to the SIM800L is a true differential type, equal resistors in both signal lines may work better (eg. 10K in each), plus the 1K across the mic input.

And, add the 47 or 100 Ohm directly across the DFPlayer output?


Nigel - the SIM800L datasheet gives signal-to-noise at a signal level of 0dBM0, so around 600mV should be acceptable, presumably via some built in AGC?

It certainly should not need to be at low millivolt levels.

10:1 should be more than adequate reduction.

10kseries to the output base of the speaker and1kto the ground andMicrophone + Well, this method I tried did not workCan you give a schematic?