I'm having trouble sending commands to the GSM/GPS/3G module from Adafruit. It gives me status data at bootup without any issues (takes a few seconds).
The product in use is this: https://learn.adafruit.com/adafruit-fona-3g-cellular-gps-breakout?view=all#pinouts
The guide says (all be it at the very bottom) that a battery is required. And that might be the case. However I've managed to recieve data from the breakout board, but I'm struggling with sending data to the board.
I'm mainly wondering if anyone else has managed to drive this board without a LiPo battery?
I'm planning on putting it in a car where I have a constant power source, with a 5V regulator that can handle a few amps. The board boots, looks to behave normal, except that I can't send anything in on the RX pin.
- 5V -> 5V regulator (12-18V power supply)
- GND -> 5V regulator/Power-supply ground
- Vio -> Tried both 3.3V on the Arduino, 5V on the arduino and 5V regulator
- RST -> D4 on Arduino
- RX -> D2 on Arduino
- TX -> D3 on Arduino
- Key -> Ground
Two antennas connected, and that's about it.
The code I'm using is this one: https://pastebin.com/N0Yn5udm
And the result looks like this:
Again, when I send the AT command, I get nothing in response. The I know it's been sent because the internal LED flickers pretty quickly.
I've run out of ideas except pulling ~3.7V from a voltage divider or regulator off the 5V supply and plug that into the JST connector. Unfortunately I don't have any JST's at home.
But if a battery is the only way out, I'd like to learn why that is. Because there aren't much information for this module, only a tutorial saying "That's just how it is".