The EED board begins an algorithm after launch is detected that determines whether or not the rocket is flying along its expected trajectory. The EED board then sends firing signals to the motor/payload separation mechanism and to the recovery system deployment mechanism at the appropriate times.

EED Board Interfaces:

EED Battery to EED Board The EED board will connect to a +18V battery pack which will power the board, and to a +9V battery pack which will be used by the firing circuit. Connections to the batteries will be made with 9V battery connectors.

Accelerometer to EED Board Three lines are required for the interface between the EED board and the accelerometer. These lines allow the EED board to monitor the longitudinal, radial, and tangential acceleration outputs. A 4-conductor standard data cable will be used with 4-pin Molex connectors at each end.

Flight Instrumentation Board to EED Board One line is required for the interface between the EED board and the flight instrumentation board. This allows the EED board to monitor the ambient air pressure measured by the flight instrumentation board. A standard 4-conductor data cable will be used with 4-pin Molex connectors at each end.

Status Switches to EED Board Two lines are required for the interface between the EED board and the status switches. This allows the EED board to determine if the payload has separated from the motor, and ifthe recovery system deployed. Each of the lines will connect to a Winchester connector, and both of the lines will connect to a 4-pin Molex header on the EED board.

EED Board Activation Signals The EED board will connect to a motor/payload separation activator and to a parachute deployment activator through a 4-pin Molex Microfit connector.

 

The EED algorithm and HC11 code that we are planning to fly is posted here:

http://volt.ee.uaf.edu/~fsspb/steve/asgp/srp4_eed_firmware/srp_eed_firmware.htm