Early this year I was trying to find a good tracker for my Phantom, but they either didn't have the features I needed and/or weighed too much. Since then, I've been working on my own device and have gotten to a phase where I can show you guys what I've come up with. The device is based on my favorite MCU - the Teensy 3.1, that some of you probably know well. The GPS/GSM is a backpack that is connected directly to the Teensy, yet leaves many pins free for further development and features. There is also an on-board CAN transceiver and DC-DC converter for up to 30V input. But it is especially designed to run off a very lightweight 1S LiPo, since we generally don't need hours or days of runtime. A NanoSIM slot is used for GSM. Mainly though, the whole device has to be as light as possible. Currently its around 20 grams and a 350mA LiPo weighs around 15 grams (180mA Turnigy even less). Consumption is around 100mA. The device sends the Phantom's GPS info (not directly from the Phantom for redundancy), own battery info, etc. to a server every 10 seconds. SMS and call commands can be sent to the device, returning a location SMS, or tuning on a high pitch beep from a speaker for example. This is what it currently looks like: * I usually have a very small GPS puck on it The GPS/GSM board is the same size as the Teensy (cca 3.5x1.75cm). Input connectors for Bat and Vin. Antennas connectors can be soldered above or below. CAN connector and SIM slot. I think there's lots of options for input from the community, since the software is open source and Arduino friendly. Admittedly, its a device primarily for the hobbyist/tinkerer, but I'm sure that is the predominant type of user here. I'll be glad to answer any questions or comments.