Altus Metrum EasyMini

This is a small, baro-only recording dual-deploy altimeter for model rocketry

EasyMini version 3.0 is available from the Garbee and Garbee web store and from our distributors.

For the latest EasyMini firmware and related ground station software, please visit the AltOS page on this site. EasyMini version 3.0 requires AltOS version 1.9.12 or later.

These are photos of version 3.0: 

Features

User View

• Recording altimeter for model rocketry
• Supports dual deployment (can fire 2 ejection charges)
• Barometric pressure sensor good to 100k feet MSL
• Designed to use a battery supplying 3.7V-12V.
• 1.5 x 0.8 inch board designed to fit inside 24mm airframe coupler tube
• 1MB on-board data logging flash
• Weighs only 6.5g (less than 1/4 oz)

Developer View

• Hardware Features
  • NXP LPC11U24System-on-Chip.
    • ARM Cortex-M0 MCU
    • 32k Flash
    • 8k RAM
    • USB 2.0
    • 10-bit analog inputs
    • I2C, SPI, async serial
    • digital I/O
  • Measurement Specialties MS5607 pressure sensor
  • 1MB SPI flash
• Software Features
  • Written mostly in C with some ARM assembler
  • Runs from on-chip flash, uses on-chip RAM, stores flight data to flash memory part
• Tools Used
  • lepton-eda for schematic capture
  • pcb-rnd for PCB layout
  • GCC compiler and source debugger
• Licenses
  • The hardware is licensed under the TAPR Open Hardware License
  • The software is licensed GPL version 2

Artifacts

There is a shorter manual for EasyMini which is available in html and pdf formats. EasyMini is also documented in the comprehensive Altus Metrum manual in html and pdf formats

An outline of the board with drill hole locations is available in pdf format.

Thanks to Bryan Duke, there's also a 3d model of EasyMini available on Thingiverse.

The hardware design files can be found on git.gag.com in the project hw/easymini.

For those who don't have ready access to the gEDA suite, here are pdf snapshots of the files for production PCB version 3.0 in pdf format.

• schematic
• pcb artwork
• bill of materials