Project Overview:
- It Sure Is Getting Hot In Here (henceforth ISIGHIH) is a gumstick sized data logger intended to log data from two Resistance Temperature Detector (RTD) sensors to measure aerodynamic heating during flight.
Hardware -
It Sure Is Getting Hot In Here (ISIGHIH) copies the RP2040 and surrounding circuitry from LEO and Hope to facilitate the accelerated timeframe and to increase the chances of getting the design right the first time, rather than needing a revision. It uses an RP2040 MCU with two MAX31865 RTD reader ICs and a BMI088 IMU, which interface with the MCU over SPI and I2C respectively.
The boards were assembled by JLCPCB, and are four layers. The board was made as small as possible while retaining 0402 components and one sided assembly. The IMU had to be placed on the back, but this was deemed acceptable to hand solder.
Software -
The software for ISIGHIH was directly adapted from LEO with the non present sensors and sensor fusion stripped out. The firmware logs the two channel temperature channels to the flash chip along with the IMU data and some other metrics like computer uptime and flight time.
Integration -
ISIGHIH is designed to be integrated into the nosecone section of amateur rockets by VHB taping it down to a flat surface. Connectors come off of the solder pads and go to the RTD sensors embedded in the nosecone to read the wall temp on both the outer and inner surfaces.