Introducing MicroPeak by AltusMetrum

Micropeak is a barometric logging altimeter for precision model rocketry altitude measurements.

Data download is available using the MicroPeak USB adapter.


The MicroPeak manual is available in html and pdf formats.


The MicroPeak application runs on Linux, Mac OS X and Windows. It communicates with the MicroPeak USB adapter to download and analyze flight data. It's written in Java and offers the same functionality and interface on all three platforms. It uses the FTDI USB Serial drivers to communicate with the hardware. If you're running Mac OS X or Windows, a compatible version of those drivers is included with the software. You can also install a different from from the FTDI Driver page.

MicroPeak is part of the larger AltOS suite of software, which also includes a dedicated TeleGPS application.

Available Versions

Release Notes for Version 1.9.7

Version 1.9.7


  • Fix TeleGPS logging so that new data are appended to an existing log correctly


  • Support Mac OS X 11 (Big Sur)

  • Support Monitor Idle on Easy Timer

  • Fix TeleMega v4.0 and TeleMetrum v3.0 configuration in Antenna Down mode

  • Show launch sites in Load Maps view

  • Add IMU header names to CSV files

  • Clean up TeleGPS log corruption due to firmware bugs during firmware update


  • Support older devices back to Android version 5.1

  • Fix a number of issues that could result in app crashes

Release Notes for Version 1.9.6

Version 1.9.6


  • Fix EasyTimer bug where it might mis-detect boost (either detect it early or not at all) due to small errors in accelerometer calibration leading to large accumulated error in speed.

  • Adjust self-test of new 9-axis IMU (BMX-160) so that it doesn’t think the part has a failure when tested sitting horizontally.

Release Notes for Version 1.9.5

Version 1.9.5


  • Add Booster mode for all dual-deploy altimeters. Select "Separation & Apogee" mode in AltosUI to fire the 'main' channel at first motor burnout and the 'apogee' channel at apogee.

  • Improve reliability of stm32l firmware under heavy load. This was found using Monitor Idle on TeleMega with all flash slots full of data which would occasionally lock up.

  • Fix orientation label in AltosUI for devices with radios. This makes the orientation say 'Antenna up' and 'Antenna Down' for TeleMetrum and TeleMega again.

  • Fix log data for pyro channels which were inhibited (often because of a tilt limit). They used to report 'fired' as soon as they were inhibited, which was misleading. Now they never report as having been fired.

  • Allow Igniter Test to fire each igniter more than once.


  • Improve performance of Monitor Idle mode by sending less data for each update.

  • Improve Mac OS X install scripts so that they work on Catalina. This involves sending the user to get Java from the AdoptOpenJDK project which provides a version that works with Java applications.

  • Make larger dialogs scrollable for use on smaller screens.

  • Fix troubles re-flashing EasyMega boards running older firmware.

  • Add TeleMetrum v3.0 firmware to the Windows AltosUI packages.

Release Notes for Version 1.9.4

Version 1.9.4


  • Fixed firmware for TeleDongle v3.0 and TeleBT v4.0. Version 1.9.3 bricked those devices requiring them to be opened up to get them working again.

  • Fixed firmware for EasyMini v1.0. Changes in the storage code caused it to use significantly more RAM which made the interrupt stack smash into other data structures and cause the device to panic at startup time.


  • Add TeleMetrum v3.0 firmware to the Linux and Mac OSX AltosUI packages.

Release Notes for Version 1.9.3

Version 1.9.3


  • Add APRS offset. Allows multiple APRS transmitters to coordinate when transmission occurs to allow them to share a frequency.

  • Fix max log size. Flight computer storage is erased in 64kB chunks. Adjust max log size to be a multiple of this size.

  • Check flight erasing more carefully. Handle interrupting erasing in the middle.

  • Add EasyTimer support.

AltosUI, TeleGPS, MicroPeak

  • Add configuration support for APRS offset.

  • Adjust flight log sizes to be a multiple of the flight computer erase block size.

  • Report barometric pad altitude in Pad tab for TeleMini.

Release Notes for Version 1.9.2

Version 1.9.2


  • Add support for TeleMega v4.0

  • Fix time wrapping issue with TeleLCO and TeleFire

AltosUI, TeleGPS, MicroPeak

  • Add column in AltosUI for IMU data from TeleMega and EasyMega


  • Allow sorting of trackers by call, serial, frequency or age

  • Offer selection of font sizes

  • Various bug fixes for older Android versions

Release Notes for Version 1.9.1

Version 1.9.1


  • Add support for TeleMetrum v3.0

  • Fix accel cal value when changing EasyMega v2.0 pad orientation

  • Correct EasyMega v2.0 magnetometer data axes

  • Fix EasyMega v2.0 idle monitor display of IMU data

  • Report all sensor failures at power-up time.

AltosUI, TeleGPS, MicroPeak

  • Display error message when attempting to graph unknown format file.

  • Make it possible to disable APRS once enabled.

  • Display some data for point near cursor in map tab.

  • Support upgrading devices from pre-1.8 firmware

  • Wait for Windows to prepare new devices during firmware upgrade. This should avoid the “COMxx: open failed” message.

Release Notes for Version 1.9

Version 1.9


  • Add support for EasyMega v2.0

  • Replace C library for ARM devices

  • Remove support for 8051-based devices and SDCC compiler

AltosUI, TeleGPS, MicroPeak

  • Select ROM images based on product name when reflashing

  • Fix TeleGPS v2 battery voltage display

Release Notes for Version 1.8.7

Release Notes for Version 1.8.7

Version 1.8.7

1. AltOS

  • Include TeleMega v3.0 firmware

2. AltosUI, TeleGPS, MicroPeak

  • Poll for new devices while Device dialog is displayed
  • Wait for device to re-appear when flashing new firmware
  • Fetch correct TeleBT v4.0 RF calibration values from web site when reflashing.
  • Change gyro headings in .csv files from x/y/z to roll/pitch/yaw
  • Add documentation about Packet Link mode
  • Add documentation about forcing TeleMini RF parameters to known values.
  • Create a proxy server for Google Maps to re-enable map images
  • Fix Java version info in all distributed jar files so that applications will run with standard Mac OS X Java.
  • Replace JavaApplicationStub for Mac OS X so that applications will run with Oracle Java.

Release Notes for Version 1.8.6

Release Notes for Version 1.8.6

Version 1.8.6

1. AltOS

  • Use maximum of 64 previous tilt values in pyro tilt tests
  • Eliminate 100m height requirement for coast detection
  • Change After Motor pyro check to be >= instead of ==
  • Change Time since Boost to be Time since launch.

2. AltosUI, TeleGPS

  • Clarify pyro test phrasing
  • Remove ascending/descending from pyro config UI
  • Fix accel calibration in Antenna Down mode
  • Add mag sensor reporting for TeleMega v3 idle monitoring.
  • Fix radio parameter saving at 2400 bps telmetry rate.

3. MicroPeak

  • Report altimeter-recorded maximum height value

Hardware Features

  • Measure ground pressure and peak altitude pressure.
  • Logs 48 seconds of flight data
  • Orange LED blinks out maximum height in decimeters.
  • 18mm x 14mm. 1.9g including battery.
  • Power switch.

The CR1025 battery holder is mounted on the back side of the board, so there are no external wires or batteries to manage.

Software features

  • Saves last flight data to non-volatile memory.
  • Reports previous flight on power-on.
  • Automatically shuts down on landing to preserve battery.

Battery Holder

MicroPeak includes an integrated battery holder on the back side of the circuit board.

Developer View

Here's a close-up view of the hardware

  • Hardware Features

    • ATMEL ATtiny85 Microcontroller
      • 8K flash
      • 512B RAM
      • 512B EEPROM
      • SPI/I2C interface
    • Measurement Specialties MS5607 Micro Altimeter Module
      • Wide range — 120kPa to 1kPa (approximately -1500m to 31000m)
      • High precision — 2.4Pa resolution (approximately 20cm at sea level)
      • Factory calibrated.
    • CR1025 Lithium Battery
      • 30mAh. Runs MicroPeak for more than 40 hours on the pad or in flight
    • OSRAM LO T67K orange LED
    • Standard 6-pin AVR programming interface.
  • Software Features

    • Written in C
    • Samples pressure every 96ms
    • Delay 30s after power-on to finish airframe prep
    • Detect boost with 30m altitude change
    • Exponential averaging filter to minimize transient effects.
  • Tools Used

    • gEDA for schematic capture and PCB layout
    • GCC as an AVR cross-compiler
  • Licenses