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NERO Projects E-36 Rocket Electronics

The E-36 Onboard Electronics


Measurement system

In order to perform measurements during flight we use micro controller based hardware. The E-36 rocket will be equipped with two Philips 80C552 micro controllers. One controller is used to perform the actual measurements in real-time, the other one is used to collect the results and transmit the as AX.25 packets using a 2-meter transmitter. The micro controllers are connected using the I2C serial bus.

Besides the controllers several analogue circuits and transducers are needed for the actually measurement. Among others, temperature, pressure, and rotation measurements are performed.


Parachute backup timers

In order to minimize the change of a crash landing, separate timers are used to activate the parachutes. These timers have there own battery system. The U-12 (launched summer '94) successfully used such a timer, and so did the E-39.

The timers were also used for the E-36, where they are monitored by the measurement system using opto-couplers. This information can therefore be transmitted to the ground base.


Ground base system

Down on earth we use a 2-meter receiver to receive the AX.25 packets. These packets are unpacked by another 80C552 system and information is sent to a PC for permanent storage and visual presentation.

Homing transmitter

To make it easy for finding our rockets back, several of the rockets are fitted with tiny 144 Mhz homing transmitters that have proven to be crash resistant.

Blue=new Red=visited At this page we will explain how to build a very small tracking transmitter used by Radio Amateurs for fox hunting. The objective of a fox-hunt is to locate a hidden transmitter in as short as possible a time. This basically covers the need of many rocketry amateurs who are very eager to find their precious equipment back.

Overview of the E-36 onboard electronics. The battery pack (yellow) and recovery buzzer (black and red) are clearly visible.

Backside of the electronics. Note that, except for a few ignition and analogue cables, all PCB's are connected by one flat cable only!