As part of our academic degree at CentraleSupélec, we have to do several projects. We were involved in Supsat, the student association aiming to work on a nanosatellite (also known as Cubesats).
Our goal there was to work on an automatic satellite tracker. Before our project, students used a QFH antenna:
- Pro: this antenna is omni-directional (no need for a tracker).
We decided to work for a directive antenna where the gain is higher but where a tracker is necessary to make good measurements. We found some related on Instructables, but we wanted to do one ourselves.
- Interested to work on a real application such as space technologies.
- Electronics + kind of wireless transmission: this is an IoT device.
- Furthermore, as we worked with widespread wireless chips, we will be able to use the driver for other projects with the same chip for Nordic Semiconductors.
- Automatic tracker (azimuth/elevation values obtained from another software such as Gpredict or Stellarium).
- No wires between the computing unit and the motor itself.
Therefore, our project is based on the following schematic:
- A RaspberryPi 3 is used as the computing unit: a bit powerful, but in the final version, we should be able to run everything (OS, GUI, Gpredict) on the Raspberry.
- NRF24L01 for the wireless transmission: these are 2.4GHz chips with a built-in antenna and an acceptable range (up to 30 meters indoor !).
- An Arduino with the official motor shield.
- Servo and a stepper motor.
- In this schematic, we forget the mechanical issues: pliers to control the antenna, etc... Furthermore, we consider that motors will be powerful enough to drive the directional antenna.
Connections of NRF24L01 chips follows:
In the attached files, you will find the sender code (C code to be compiled with default GCC settings on the Raspberry) and the receiver code (Arduino stuff).