Posted 11/11/2018

This prototype data logger has been assembled for testing in a low cost ascent system. This system is oriented towards use with either an Estes rocket or a helium balloon of a couple cubic feet size on Earth. Parts count is minimized to reduce mass and enable smaller rocket or balloon. No solar panels for this baby.

The board used is an Adafruit M0 datalogger board with the following features:

• ATSAMD21G18 ARM Cortex M0 processor
• 48 MHz and at 3.3V logic
• 256K of FLASH and 32K of RAM
• Built in USB so it has USB-to-Serial program & debug capability built in with no need for an FTDI-like chip.
• Connector for (Adafruit) 3.7V Lithium polymer batteries and built in battery charging. (I used a surplus battery and a cable from some other gadget for the end after verifying the polarity of the connector.)
• 5.3 grams
• Hardware Serial, hardware I2C, hardware SPI support
• 8 x PWM pins
• 10 x analog inputs
• Built in 100mA lipoly charger with charging status indicator LED
• Pin #13 red LED for general purpose blinking
• Power/enable pin
• 4 mounting holes
• Reset button

The board system as of today logs the data to the micro-sd card and the code is being updated to be more modular. Battery support is built in and the board has run using a surplus 600mAh lithium battery for hours. I used a low cost accelerometer instead of a full blown IMU because the flights will be short and navigation is not needed. I used the BMP280 for pressure and temperature as these can be used to estimate the altitude.