Feather Fona Corrupt In Use

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samdevon1
 
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Joined: Sat May 24, 2014 2:59 pm

Feather Fona Corrupt In Use

Post by samdevon1 »

Hi,

I have 25 feather Fona units and three of them have stopped working and stopped sending SMS whilst powered and in use. They are all powered via the 5v (USB) and GND pins and have a 5000mah lipo connected. For 8 hours the setup is powered by 5v and this also charges the lipo. For the remaining 16 hours, the setup is powered by the lipo. They send an SMS every 60 seconds.

The three units that suddenly stopped working in use are 'Not recognized' when plugged into the computer via usb. I am reluctant to just double click the reset button and install blink as I want to understand why they suddenly stopped working and essentially corrupted themselves in use.

Does anybody have any insight into this?

Thanks, Sam

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adafruit_support_mike
 
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Re: Feather Fona Corrupt In Use

Post by adafruit_support_mike »

It's almost impossible to tell without detailed information about the operating conditions before they failed.

Go ahead and try to reprogram them with the 'fonatest' sketch. If you can get them working, the most likely suspect for the failures would be marginal supply power.

samdevon1
 
Posts: 2
Joined: Sat May 24, 2014 2:59 pm

Re: Feather Fona Corrupt In Use

Post by samdevon1 »

Hi Mike,

Yes, I agree it is very difficult as there are a number of possibilities.

However, since the original post, I realised that the antenna position (5dbi gain) is too close to the Fona. In addition, I think the USB cable, which is always attached to the Fona is acting as an EMF conductor and causing issues.

If it turns out to be the marginal power supply, is there any mitigation you recommend?

Thanks, Sam

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

Re: Feather Fona Corrupt In Use

Post by adafruit_support_mike »

The general idea is to monitor the supply voltage and shut the FONA down before the voltage gets low enough to cause memory corruption issues.

An external voltage monitor like the KA75330 can shut the Feather down when the LiPo voltage gets too low:

https://www.adafruit.com/product/3428

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