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Modified MAX9814 Microphone for FPV Quadcopter Use
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Modified MAX9814 Microphone for FPV Quadcopter Use

by BikeGuy on Thu Jan 10, 2019 5:35 pm

Hey eveyone!

For about the last year and a half I've been flying FPV mini quad copters. One of the bigger names that got me interested in FPV was Steele Davis (aka Mr Steele) and he has his own PDB that has a mic build in. Well, if you happen to be using his frame or a Alien frame from ImpulseRC, his PDB will match up correctly no problem.

Well, I've gotten so used to using a earbud to hear what the quad is doing when really far out that I've been putting a MAX9814 mirophone on any quad that doesn't have a Steele PDB. I've gotten more into racing this past year and hearing what your quad is doing around the track with four to seven other quads up in the air at once is hard to track what you're actually doing. The mic works great, the only downside to it is the actual mic itself.

The mic is physically too tall for my builds that I have, so I started looking around for a possible replacement mic to swap in. And this is what I found.

https://www.onlinecomponents.com/cui-in ... 00269.html

http://download.siliconexpert.com/pdfs2 ... 15-42p.pdf

I just got ten of them in the mail today and got one swapped onto a MAX9814 that had the mic fall off of it due to in-flight vibrations. Usually I'd just super glue the stock mic down, but my builds are getting tighter and tighter so going with the CUI CMC-6015-42P was a must. Besides that, I'm able to flip the MAX9814 board over so the SMD components are on the top instead (see photos).

Not only does this make it easier to mount, but makes the entire profile sit way lower. I did put two layers of acrylic conformal coating since it has the electrical barrier properties that come with it. Applying the conformal coating was a must, even though the mic doesn't touch the caps and resistors because of how I have the CUI mic mounted, I did not want a issue with something shorting out when the mic is sitting on the board.

I just put the modified MAX9814 in a build and tested it to see if it works with the CUI mic and it does!

If there is a way, can there be a revision done to the MAX9814 to put the mic positive and ground terminals away from the couple caps and resisitors that are sitting next to the mic? Even just 1mm away from the SMD parts would be enough and possibly switch to using the CUI CMC-6015-42P mic instead to make a better fitting profile MAX9814?
One other thing too is the CUI CMC-6015-42P has pin spacing for 1.9mm +/-0.2. I had to bend the mic pins out a little and slowly push it down onto the board. Once centered, then I pushed it even further to get it as low as possible to make it sit as low as it would go.

Let me know what you guys thing and could this be implemented?

Thanks!

BikeGuy
Attachments
50103867_503881046801491_8077290044328509440_n.jpg
One of four 6s (25.2v) LiPO powered FPV racing rigs I built.
50103867_503881046801491_8077290044328509440_n.jpg (538.13 KiB) Viewed 65 times
49419744_310929979530629_5476927164689416192_n.jpg
Stock MAX9814 with stock mic and modified MAX9814 with CUI CMC-6015-42P mic. Flyduino KISS V2 FC for reference of size
49419744_310929979530629_5476927164689416192_n.jpg (80.58 KiB) Viewed 65 times

BikeGuy
 
Posts: 1
Joined: Thu Jan 10, 2019 4:29 pm

Re: Modified MAX9814 Microphone for FPV Quadcopter Use

by adafruit_support_mike on Sun Jan 13, 2019 5:48 am

Respinning the board would be expensive for us, but you're free to make your own version based on our design. The design files are over in our Github repo:

https://github.com/adafruit/Adafruit-MA ... ophone-PCB

adafruit_support_mike
 
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Joined: Thu Feb 11, 2010 2:51 pm

Please be positive and constructive with your questions and comments.