Yi 4K external mic project (electrical eng. help needed)

l30ns

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Hi, everyone!
We all know that Yi 4K lacks external mic input while it has 2 on-board mics.

My project:
1) lose 1 mic
2) solder external mic input (3,5mm female socket) to the motherboard
a) socket 4 (mic_in)
b) socket 2 or 3 (GND)
3) the magic! (hopefully I will get a stereo sound with right chanel coming from on-board mic while left channel will hold an ext mic.​

Questions and obvious problems to overcome:
  1. I have only a guess on what socket 1 is (NetC1_2) is. Some sort of phantom power for amplification I guess. AM I RIGHT?
  2. Getting the signal level to match is going to be a challenge. ANY IDEAS?
Ext mic is active Boya BY-M1, a lavalier mic with a pre-amp. hopefully I will be able to transmit the signal via Bluetooth audio transmitter / receiver dongle without background noises. This is a setup I want to food in as an ext mic.

unnamed (1).png unnamed.png IMG_20170103_155747_01 (1).jpg
 
I don't know the circuit specifics but I'd recommend staying with the type of mic that's already on the board or using it remotely after pulling it ;) Too much amplified signal going in or a different impedance could fry the cam's audio circuit or worse :(

Usually these are electret mics, and there's only about 4 different types overall where any one of a similar type will work but any from the other 3 types probably won't. I've junk-box replaced a few of these in radios that were water-damaged and there was only one where none I had worked. I ordered an exact replacement and that worked fine. Electret mics are very sensitive and don't need a pre-amp; if anything they usually need some foam over them to get the sound sensitivity down to a usable level :p

Let us know chow your project works out :D

Phil
 
If you need more info we are glad to be helpful
BTW I forgot to mention how surprisingly helpful the Yi team has been in providing the schematics and advice. Thanks guys!
 
nice can you make a quick video how to made that ? I want to external mic with my yi 4K for best sound
 
seems like a lot of work and risk, hope it's worth it.

can't wait to hear the result!
 
... as is the current status?
I am at exactly the same point. Soldering looks very complicated.
is there a simpler solution?
 
Unlikely that there is sufficient space in the plastic case for a mic.socket! There was only enough territory in one of my original xiaomi yis for jr radio female contacts!
 
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