We havent been able to figure it out ourselves yet.
The situation is that if we wire the 5V and GND pins of the our GPRS Shield to same pins on an Arduino UNO or to those pins on a FTDI cable then we can power up the Shield perfectly fine.
But when we wire it to the 5V and GND on the Telemetry connector or on the Output group of the APM2.5 board, then the Shield doesnt power up when we plug it in..
Any ideas?
We dont have a tool to measure the current/voltage right now. We are thinking that we have to configure the APM and are about to look into the source code for any hints there.
Replies
Ahh, problem solved. It was just a pin that was loose. It was halfway out of the GND on the telemetry connector. Those pins have to be really tightly secured.
this question is probably very similar to this one http://diydrones.com/group/telemetry-over-cellular-ip/forum/topics/... and thus just a question of wiring more power to the Shield.