The CanSat project can make use of just about any Micro controller (MCU). The UK Can Sat teaching guide in 2021 makes use of a Raspberry Pi Pico, an Adafruit LoRa transceiver and a BMP280 temperature, pressure and (inferred) altitude sensor.

We would be using a Raspberry Pi Pico and a Bosch BMP280 sensor to measure pressure, temperature and altitude. The Lora Modules RFM96W would be used as transmitter and receiver of this data.

Basic Electronic Parts

Raspberry Pi Pico

This is a small and powerful MCU that uses a common RP 2040 chip. It has a decent amount of onboard memory (2Mb) and a flexible power system which includes an onboard buck:boost that can accept between 1.8v and 5.5v (see the data sheet for full specs - ). The Pico accepts data from UART, SPI & I2C.

The MCU is quick and competent but will require a particular language to be used in this instance, Circuit Python. This is the only down side as it is less capable that an Arduino for instance but is perfectly capable for our purposes.

BMP280 sensor

For the basic sensor we use the Bosch BMP280 which has been combined with some extra part to allow it to be easily interfaced with. The datasheet gives a bit more detail of ranges etc. We'll be using this for the primary mission (determining temperature and pressure), we can also use it to infer altitude as the sensor can use the local air pressure (QNH using Aerospace Q codes) as a way of determining height. This is a handy extra feature but needs some careful integration.

Useful links for BMP280 Bmp280 Library Demo code All Micropython codes for this playlist

RFM96W Lora transceiver

The way we communicate between the CanSat and ourselves (the ground station) is with a low powered transmitter and receiver (transceiver) module that operates in the UHF (433MHz) band. It comes in several different frequencies but 433 MHz is the recommended frequency for the UK Cansat. These LoRa (Long Range) spread spectrum devices are typically used for Internet of Things devices to communicate with each other. This makes them perfect for this job. Ours is from Adafruit and has enough power for 2kM of range where there is a line of sight. They also have plenty of support for programming.