The TD1204 modem firmware is a easy to use solution for sending message to Sigfox network. It starts to be complex when you want to create your own message including the GPS position. The standard firmware returns the satellite NMEA frames in text mode and you have to process it.
To make it simple I built a modification of the standard modem firmware to add an extra command to enrich a message with a GPS coordinate automatically.
The TD1204 / TD1208 Raspberry PI shield is following HAT standard. Is can be use with a RaspberryPI B+ or Raspberry PI 2. It includes 3 programmable leds plus the TelecomDesign Led. Some and the GPIO of the TD chip can be read/write from the RaspberryPi, Some can be cabled on the small customization area to add you own components.
The shield can be delivered with an external antenna of use with an SMT antenna.
Telecom Design chip can be flashed with an FTDI cable or directly with the RaspberryPi
This shield is not SigFox certified so it can only be used for prototyping usage.