Electronics
Electronics
DARE designs and fabricates its own electronics packages for use in DARE rockets. These electronics package may range from fairly simple timer based designs for use in small rockets, to full flight computer designs for use in rockets like Stratos IV. One of the primary functions of the electronics in any rocket is the timely deployment of the recovery system. In a case a parachute needs to be deployed, it’s in most cases beneficial to deploy the parachute at apogee. For more complex rockets the electronics may also be tasked with igniting a second stage or recording data from accelerometers and GPS receivers. The record-setting Stratos II+ rocket also had a real time telemetry unit on board, relaying the position of the payload capsule for recovery.
Our Contributions
The electronics team creates the electronics for all projects within DARE. Below are some of the systems the electronics team has designed.
Project Aether
The Electronics Team worked on the design and development of flight electronics and software for Project Aether.
The electronics stack that is located in the nose cone of the Aether rocket consists of layers of boards dedicated to their own tasks, containing the following elements:
- Attachment Plate and battery holder (not shown)
- Power supply board
- Main processor board, including ACT software
- Actuation board for actuators
- Sensor board
- Telemetry board
The Aether electronics stack, consisting of 5 Printed Circuit Boards (PCBs).
Stratos II Electronics
Stratos II Payload Controller
Processor: 2x LPC4313 for Kalman filter computations (redundant), 1x Spartan 3A FPGA for payload data acquisition, in total 10 LPC1751 for various other tasks.
Power Source: 3x 1250 mAh at 11.1V for video downlink and payload power supply, in total 12x 450 mAh at 7.4V for various other tasks, external power supply at 12V 3A while the rocket is in the tower.
Without the ground systems, the rocket contained two electronics modules: one in the motor and one in the capsule. Both modules communicate over an RS232 link and together handled the following:
- Two independent measurement systems, with GPS, static air pressure sensor and two triple-axis accelerometers, gyros, and magnetometers, with a Kalman filter for sensor fusion, used for apogee detection and flight termination.
- A digital downlink with three independent storage systems for sensor and status data from the rocket and the payloads.
- An analog up-link for remotely shutting down the motor.
- An FPGA to merge and distribute the incoming data streams from the rocket and the payloads to the data storage and downlink.
- Fully redundant actuation system, each taking its input from the two measurement units and timers.
- Advanced independent power supplies for each system, with two battery inputs for redundancy with voltage and temperature measurements.
- Payload power supply with current consumption measurement for each payload.
Flight Termination System
To be able to include a reliable safety system in Stratos II+, the electronics team designed a flight termination system to be used over a range of more than 50km.
The system is designed to be able to terminate the flight in case of failures during launch. The flight can be terminated actively by pushing a button or in case of signal loss, the flight will be terminated automatically.
Transmitter of the Flight Termination System
Advanced Control Board
Advanced Control Board V1
The electronics team contributed with the advanced control board which can control the canards of a rocket to keep it flying as close to vertical as possible, making the landing area closer to the launch site and increasing the maximum altitude.
Processor: 1x LPC4313.
Power Source: 2x LiPo 1800mAh at 7.4V for servos, 1x 300mAh at 7.4V for the board.
CanSat V7.3
The CanSat electronics have been continuously refined and improved over the years. Based on DARE’s previous experiences, the choice was made to have 4 independent microcontrollers, two boards each controlling a door, and all with the authority to deploy the parachute. Each board also has its own power source, again for redundancy. With this approach, each board can function on its own after launch.
Processor: 3x LPC1313 for servos, 1x LPC1313 for main control unit, 1x ATmega168 for external interface.
Power Source: 3x LiPo 500mAh at 7.4V for servos, 1x LiPo 500mAh at 7.4V for main control unit.
