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Feather Fona Corrupt In Use
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Feather Fona Corrupt In Use

by samdevon1 on Tue Mar 30, 2021 11:05 am

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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Re: Feather Fona Corrupt In Use

by adafruit_support_mike on Wed Mar 31, 2021 10:45 pm

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.

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Re: Feather Fona Corrupt In Use

by samdevon1 on Thu Apr 01, 2021 5:33 am

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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Posts: 2
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Re: Feather Fona Corrupt In Use

by adafruit_support_mike on Thu Apr 01, 2021 5:53 pm

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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Please be positive and constructive with your questions and comments.