Core Flight Components

This is the core of the payload. It is a BeagleBone Black Enhanced(BBE), (made by SanCloud, the really great guys who helped me out with a new board). The board has an internal barometric pressure sensor, temperature and MEMS sensor which measures it's X, Y, Z position and it's acceleration in any direction. All of these sensors will be read as frequently as possible and logged to file so that when the payload is recovered, accurate data about the entire flight can be reconstructed.
The BBE has a Mikroelecronika expansion shield, allowing support for their propitiatory 'click' boards (be careful ordering things from this american company, they don't pay the customs and excise charges the postie will lump those charges on top of your delivery for you). This Click expansion board allows for 4 sub boards to be plugged in.

The purpose of the core flight computer is for payload recovery. There is a GPS module (shown here in slot 2). This module is based around a Quectel L30 chip, a UART controlled device that, when correctly turned on, (turn on three pins, wait, turn on off, wait, stand on one leg and stick your finger in your ear), spews out its GPS location in the form of a NMEA protocol stream.

This stream is parsed and rehashed into UKHAS Habitat protocol, which is then kicked out of the radio (shown here in slot 1). The radio is a Radiometrix NTX2 which was initially designed as an FM radio, but by simply shifting the carrier frequency, an AM radio can be tuned to pick up the two different frequencies as two tones, and transmit RTTY back down to the ground at flight time.

The GSM module (in slot 4) is a Telit GL865-Quad which, when furnished with a SIM card will not only act as an emergency backup location transmitter, but will also be used during flight time to send text messages to a twitter feed to update the world with it's location and a bit of info on how happy it is (or not!)
The last module (Slot 3) is a Dallas 1W Temperature sensor for external measurements.

Here is an exploded view of the entire core flight computer component of the payload. There will be more devices in the payload, such as camera's etc. but this will all be described in another blog post.