This is another old project that I just finished – a flight computer with programmable outputs. This flight computer is based on my small digital barometric altimeter, the small accelerometer and the UV apogee sensor.
This flight computer has excellent functionality with 4 high current outputs and the possibility for installation on the outer surface of the rocket body. The main characteristics are:
– Barometric altitude measurement up to 18km
– High g acceleration sensor
– External temperature digital sensor
– Audio buzzer for audio indication and tracking purposes
– 40 samples per second / 13 bit ADC
– 7 minutes recording time
– Igniters connectivity check for all four channels (LEDs for each channel will show the status of the igniter)
– USB connection
– Serial (USART) port for future communication with wireless telemetry
– 6.5 to 16 VDC power supply with on-board ON-OFF switch
– 20A (60A pulse) MOSFET for each channel
– Selectable on-time for each channel (between 0.1 and 5 seconds)
– Selectable apogee detection method (UV sensor or barometric sensor)
– 4 individually programmable outputs where each output can be set up for one of the following events:
1. DISABLED – Output won’t fire
2.TIME – Fire after the time elapsed (in seconds)
3.ALTITUDE – Fire as soon as the predetermined altitude is reached (in meters)
4.APOGEE-IMMEDIATELY – Fire at apogee
5.APOGEE-TIME DELAY – Fire n seconds after apogee
6.APOGEE-ALTITUDE – Fire at a predetermined altitude after the apogee has been reached (in meters)
7.STAGE BURNOUT – Fire as soon as the initial acceleration falls below 1 (motor burnout)
The big difference between this flight computer and other computers is the possibility for frontal assembly on the surface of the rocket fuselage.
In order to do that the PCB and the computer assembly is a little bit different than the usual.
Nevertheless it’s a nice functional device and here’s how it looks like assembled:
The electronic and functional diagrams are shown next:
Then the next part was to write a suitable desktop application for the USB communication part. This wasn’t really new software because it is based on my other flight computer application with minor modifications.
The flight computer passed so far the testing in my improvised barometric chamber and I hope soon to be tested in a real flight.