Faulty 3G Fona Module?? Moderators: adafruit_support_bill, adafruit

[Agriculex]

I have two 3G Fona Module (North America version). The first one bought directly from Adafruit 8 months ago and the second module was bought about 2 month ago from Digikey.
Both module have "PCB adaptor" soldered to it to use a FFC cable & connectors to interface with my custom made Arduino board. The code that works with the module is taken from the Adafruit_FONA library.

The first module bought directly from Adafruit worked flawlessly with my Arduino code and easily connected to the cellular network. However, the second module from Digikey is NOT working as expected. With the same SIM card, antenna, Arduino, and code, it seems to be having issues with network connection.

Now, it does connect to the network after a while (NET LED flashes 800ms) but it's in a useless state. Whenever I open or close the serial monitor, both the PWR and NET LED turns off for a few seconds and turns back on and stays on. During that time, I keep getting the timeout and couldn't find Fona message on the serial monitor. Then the NET LED starts flashing 800ms.

I'm assuming there is a defect with the module bought from Digikey. Anyone else experienced this issue or knows what's going on?

[mikeysklar]

@agriculex,

Are you using our Lipo battery with each unit? We do have an entry in the FAQ about flakey auto-shutoff behavior with 3rd party batteries. I didn't see a mention that you had been testing with a battery or moving between devices.

https://learn.adafruit.com/adafruit-fon ... akout/faqs

Would you mind uploading a photo of your wiring so we can see if anything seems out of place.

[Agriculex]

@mikeysklar

For the LiPo batteries I used, they should be from Adafruit as they're bought from Canada Robotix who is an Adafruit Distributor. With the first 3G module I bought (that worked fine without any issues), it worked even without a LiPo battery. As a result, I initially tried the second module without the LiPo battery. Even when I tried using the second module with a few different LiPo batteries connected, it was still the same problem.

I took photos of my setup. Note that my first module worked on the same setup as shown in the photos even without the LiPo battery. For the wiring, module is connected to the a custom Arduino Mega board I made through a FFC. The FONA_RX, FONA_TX, and FONA_RST pin is connected to D11, D10, and D12 respectively. They share the same 5V and GND line.

Overall Setup

IMG_4658S.JPG (117.99 KiB) Viewed 142 times

Closer Look on the Module

IMG_4659S.JPG (108.05 KiB) Viewed 142 times

Module During Operation (Powered ON)

IMG_4661S.JPG (104.91 KiB) Viewed 142 times

[mikeysklar]

@Agriculex,

Let's back up a step and remove you custom board / code and try a basic network connect test with the new board.

https://learn.adafruit.com/adafruit-fon ... twork-test

Our FAQ is loaded with the LiPO battery being necessary to power the FONA so we should stick with that for now.

[Agriculex]

@mikeysklar

So I called Digikey and got a replacement unit. Tested the replacement unit on a breadboard with a Sparkfun Pro Micro. Got the same issue initially until I changed the baud rate in Serial.begin() from 9600 to 115200. However, this change didn't do anything for the problematic (second) unit that started this whole thing.

Breadboard Setup w/ the Replacement Unit

IMG_4672S.JPG (883.61 KiB) Viewed 115 times

After comparing the two units, I did notice the problematic unit has a different SIM card holder and placement of the SIM card during insertion is slightly different as well. I'm guessing that might be the issue. Anyways, my issue is solved with the replacement module.

SIM Card Holder

IMG_4673S.JPG (1008.49 KiB) Viewed 115 times

Different Hinge System on SIM Card Holder

IMG_4675S.JPG (903.2 KiB) Viewed 115 times