Arduino UNO w/o shield SMS problem

[Gab]

[donjohnii]

You're overdriving the board... the voltage on the Vin line is supposed to be a regulated 3.4-4.2V if it's an input. You should be shorting Vin to Vref if you're not using the shield as the shield shunts those pins together to run the 5V line through the regulator.

This is referenced on the main cell page:
http://www.sparqee.com/portfolio/sparqee-cell/

Here is the datasheet with explanation for pins:
http://www.sparqee.com/wp-content/uploa ... et_v10.pdf

The sound may be an indication that the power supply is being supplied a dirty power source, voltage range issue, low current, or main inductor is bad.

To validate that the module is getting the right power, you can make sure there is about 3.5V on Vo - this should be measured by the positive DMM lead on Vo (pin 9) and the negative on GND (pins 20, 21).

Once power is figured out, it's best to use a UART converter to communicate directly to the CELL vs through the Arduino, just to make sure it has network connectivity and everything is functioning well.