High-altitude balloon systems

I’ve been planning a high-altitude balloon launch for a long time. Initially I was planning to launch it with an AVR-based flight computer. But when the Raspberry Pi came out I decided to switch my development efforts, like this guy and this guy. I spend my days mostly developing at a fairly high level of abstraction so I feel most confident working at that level. Being able to program the RPi in Python is huge for me.

Figure 1

The plans for the payload are still in evolution, but here’s what I have so far:

  • Raspberry Pi will be the main flight computer
  • We will get barometric pressure (and therefore altitude) data from a BMP085
  • 3-axis acceleration data will come from an ADXL335 analog accelerometer connected to an ATtiny261 chip which will connect to the RPi via the I2C bus as described here. (The diagram shows an 861. I think the memory footprint needed is much lower than that.)
  • Humidity data from inside the payload and outside will come from two analog humidity monitors also connected to the AVR ADC-I2C bridge.
  • We will get real-time clock data from a DS1307 on the I2C bus.
  • Imagery will come from a Canon PowerShot G6 connected to the RPi by USB. We’ll use gphoto to capture images.
  • Flight data will be dumped to a USB-connected giveaway flash drive that I got from a conference.

There are still design decisions to be made, mainly how to command a cutdown, and how we’ll transmit the telemetry data. As an amateur radio license holder (KD0RXD), I have a number of options but I need to sort through them systematically.

Questions? Comments? I’m on Twitter @NSBum.