Parts / Assembly - Black Box
First up we'll need to charge the unitYou can charge the unit using the mini USB port. This is for charging only, not for data transfer. The battery LED will either be red, amber or green based on its charge. You can find a detailed status sheet for the LED indicators here:
Next, insert a microSD card into the slot
The holder is located quite far into the slot so you'll need to push the card in with a small tip (like a small screwdriver). Make sure that it clicks into place.
Connect the external sensors
To turn on the Black Box
Push the yellow button on top. The unit will automatically start up and begin looking for satellites.
The data LED will shine amber whilst the unit is powering up. Once it has started to record data, it will shine green.
Once you've finished recording, press and hold the yellow button for 5 seconds.
The lights will flash for one final time and then the unit can be switched off at the side (by pushing the slider switch away from the wire).
The black box dataThe data comes off the card in 4 different file types. Acceler, Atmos, Magnetom, Position. Each file number is continuous from the last (split up so that if the worst happens and you land in water corrupting the electronics or something similar, you'll only ever lose the final data file). The data from each file is as follows:
AccelerTimestamp, X acceleration, Y acceleration, Z acceleration, board heaters on/off The accelerations (as with any other directional data) align with the box as shown below:
Board heaters are used to maintain the temperature of the circuits. We've included a check to see whether they were on (1) or off (0).
The atmospheric data files contain; timestamp, circuit temperature (C), external temperature (C), pressure (mbar) and humidity.
The magnetometry data files contain; timestamp, X magnetometry, Y magnetometry, Z magnetometry, battery voltage.
Position data files are in the form of two sentences of NMEA data. Simply put, this means that there are two lines of GPS data for each time stamp. These are $GPRMC and $GPGGA.
$GPRMC includes:Time Stamp validity (A-ok, V-invalid) current Latitude (North/South) current Longitude (East/West) Speed in knots True course Date Stamp Variation East/West checksum $GPGGA includes Time Latitude (North/South) Longitude (East/West) Fix quality (0 = invalid, 1 = GPS fix, 2 = DGPS fix) Number of satellites in view Horizontal Dilution of Precision (HDOP) - the relative accuracy of horizontal position Altitude (m) Height of geoid above WGS84 ellipsoid (m) Time since last DGPS updateGPS reference station id Checksum