Peanut Altimeter with my fingers for scale
Peanut Altimeter powered up and operational
Peanut Altimeter KiCAD render
A modern, tiny, and hackable altimeter for hobby rocketry. Features include:
- Fits in a min-diameter 29mm rocket
- High accuracy barometric pressure sensor (up to ~9km)
- Dual deploy capable (two pyro channels)
- Visual continuity LEDs
- On-board 2MB storage (4MB, 2MB for program, 2MB for logs)
- Altitude measurements
- Flight events (ascent, apogee, landing, etc.)
- Deployment events
- Mach dip filtering (works on flights that break Mach)
- Audio arming indicator
- Bluetooth connection
- Deployment testing with flight simulations over BLE
- Configuration over BLE
- Continuity & other telemetry over BLE
- WiFi capable
Thank you to PCBWay for sponsoring the manufacture of this project's PCBs!
The firmware for this board is made using the Apache NuttX RTOS, an open-source embedded RTOS with an incredible community and an excellent feature set.
Firmware is spread across a few repositories. If you are compiling yourself, you'll need:
- The NuttX kernel source
- The NuttX application library
- The Peanut board support package
- My application-level altimeter software
All hardware designs & firmware for Peanut are open-sourced and available under permissive licensing.
The device itself is programmable over the USB-C interface, so users can tweak the firmware or write their own and re-program the device. Want the buzzer to play custom audio? Want to change the meaning of the "START" LED? Want to add more features to the Bluetooth interface, or make the altimeter operate over WiFi instead? You can program whatever you want into it.
If you want to make your own Peanut Altimeter, the component cost for the board is roughly $30 CAD. You can get PCB blanks from a manufacturer of your choice (i.e. PCBWay). You should only need to verify the trace widths of the Bluetooth RF trace depending on the differences between your manufacturer's PCB stackup and mine.
NOTE: This board was not designed with hand-soldering in mind (aside from the backside). My manufacture process is to use solder paste, a stencil and a hot plate to do the top-side components. There are 0402 components which are manageable with steady hands and tweezers.
My experience using PCBWay could not have been easier. They provide a plugin for KiCAD that directly exports your manufacturing files for order to their web quote interface. I only hand to click the button and choose some parameters for my board to get everything ordered.
My designs arrived on time, well package and the stencil was really high quality with a large aluminum frame. I had no issues with the fine details (in copper and on silkscreen) with such a small board, PCBWay nailed it.