# Hearing noise when combining DFPlayer and SIM800l

**URL:** <https://forum.arduino.cc/t/hearing-noise-when-combining-dfplayer-and-sim800l/658025>\
**Category:** Audio\
**Created:** [May 31, 2020, 7:54am UTC](https://forum.arduino.cc/t/hearing-noise-when-combining-dfplayer-and-sim800l/658025 "2020-05-31T07:54:43Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![arjanpals](https://avatars.discourse-cdn.com/v4/letter/a/e8c25b/32.png) [@arjanpals](https://forum.arduino.cc/u/arjanpals)\
**Post date:** [May 31, 2020, 7:54am UTC](https://forum.arduino.cc/t/hearing-noise-when-combining-dfplayer-and-sim800l/658025/1 "2020-05-31T07:54:43Z")

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Dear Arduino friends,

For some time now I have been trying to make a 'Smart Birdhouse' for in the garden. For example, you can send a Text message to the birdhouse you'll get a reply with temperature etc.

But I want to add a new feature to the Birdhouse: if you call it, the current state will be read.

So that's why I bought myself a DFPlayer mini to play audio files, my idea was to connect the output of the MP3 player to the MIC input of the GSM Module. So this is exactly what I tried, with the DFPlayer\_mini library implementing the MP3 code was a breeze. But when I called the GSM module, it accepted the phone call but I didn't hear much.

Because there is a little LED on the MP3 module you can see if it is playing or not. When this LED went on, there was a lot of noise in the phone call, I tried connecting the output to a speaker and I heard the same noise, it seems the GSM module isn't the problem here.....  
I tested both modules separately and they work perfectly. But when i connect them together the noise comes back again

Plz help me

Some extra info:  
I connected both the GSM module and MP3 module via Software Serial  
The whole birdhouse is being powerd by a 12v Lead Acid battery, and stepping the voltage down using a buck converter  
I'm using Arduino Nano  
If you need more info, just ask 🙂

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**Author:** ![MarkT](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@MarkT](https://forum.arduino.cc/u/MarkT)\
**Post date:** [June 1, 2020, 12:13am UTC](https://forum.arduino.cc/t/hearing-noise-when-combining-dfplayer-and-sim800l/658025/2 "2020-06-01T00:13:45Z")

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Are the units too close together? GSM module will push out a lot of RF, the mp3 module is presumably not screened/shielded? Ferrite beads on the wiring might be useful, RF can run along outside of cables very readily.

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**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [May 6, 2021, 4:27am UTC](https://forum.arduino.cc/t/hearing-noise-when-combining-dfplayer-and-sim800l/658025/3 "2021-05-06T04:27:50Z")

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Closed on May 6, 2021, 4:27am UTC