Ursus Minimus 1 development


Tentative Launch

December 15,2013. 11:00AM. Launch location TBD.

Mission Objectives

  • Lightweight payload.
  • Beacon APRS & 2 Meter Foxhunt signals.
  • Flight Duration 30-60 minutes.
  • GPS & Foxhunt retrieval

Foxhunt Prep

  • Map of repeaters
  • More APRS
  • Prepped radios (pre-programmed)


  • “Mike Wozowski” party balloon

Must Have Features

  • GPS
  • APRS (2m)
  • Improved Release Mechanism

Nice to Have

  • Foxhunt Beacon (2m? 70cm?)
  • Better Container
  • GPS-distance-based cutdown trigger

Pipe Dream

  • Altimeter (Barometer)
  • Temperature Sensor
  • Remote-command (for cutdown, etc.)


  • Mylar balloons.
  • Helium or Hydrogen (Party Gas to be avoided due to weak lift characteristics).

Balloon Design

Balloon weight

Element Weight
Mylar Balloon
Nichrome and lead wire
Microcontroller board
Waterproof packaging
Total ???

Electronics Design

These are images of the “Ursus Minimus 1” board we will use for this project.

Here are some procedural pictures of the solder paste and component application.

Here's a step by step of applying paste to one small section and doing the components.

This is the controller for the reflow oven.

The board, about 1/3 complete.

Code Design


Reference Links

Last modified:: 2014/05/05 15:04