Balloon, Mark 2 - "Hackathon HAB"


The High Altitude Balloon (HAB) Mk1 project is a collaboration between three Cornell Clubs:

The goal of the project is to engage in a Hackathon day to build a HAB launch vehicle and payload, and on the following day, launch, track, and recover the balloon payload. In doing so, we hope to give Cornell students some exposure to HAM radio as well as supplement their Cornell education with some additional hands-on engineering experience.

We plan to launch a latex weather balloon with a Raspberry Pi and camera payload, transmit images back to ground using SSTV, and track the balloon using APRS. To cover a broad array of interests, we will offer several sub projects such as antenna builds and the various balloon subsystems.


  • 12/31 - Survey Sent Out
  • 01/05 - Project Green Light
  • 01/24 - IEEE, CRITERS, CARC Joint Meeting (5PM)
  • 01/27 - HAM Licensing (TCARA)
  • Build/Launch Day still TBD

Action Items (Due 1/24)

  • A confirmed build/launch date
  • An alternative launch date if weather doesn't cooperate. Cold's fine, driving in dangerous conditions is not.
  • A confirmed list of participants
  • A finalized list of sub-projects
  • A list of parts for each of those sub projects and at least 50% of the list should be ordered or at least have a firm plan for sourcing those parts for build day.
  • A mapping of participants to projects (or at least a 1-2-3 ranking of what project they'd like to work on)
  • A list of people committed to taking the HAM licensing exam (again, licenses are NOT required, just icing on the cake). That way we can organize rides and such to 92 Brown Road on 1/27.


Name Affiliation


  • Burst altitude forecast models exist for some documented, but more expensive balloons.
    • Purchase more expensive “well documented” balloon ($70ish) or less predictable one ($25ish)?
    • More expensive balloons offer higher altitude missions. They also require more lifting gas (and expense) and the payload will land farther away. The proposed balloon has a targeted burst at 12,000-15,000 feet if we wish the payload to land within a reasonable driving distance (60-100 miles).
  • Do we want to buy offset attenuators and/or inexpensive radios to use with the Yagi antennas?

Project Plan

HAB Mk1 (Priority One)

Launch Vehicle Latex Weather Balloon Latex Weather Balloon + H2
Payload APRS, SSTV, Pi Camera Ursus Minimus, SSTV, Raspberry Pi, Radio
Payload container CAD design, 3D print?, styrofoam?
Max Payoad Weight 730g
Flight Time 45-90 min
Cutdown A Nichrome + Accelerant
Cutdown B Balloon Failure
Recovery Parachute? Streamer?
Tracking APRS, Beacon

Deliverables - HAB Mk1 (Priority One)

  1. Setup payload for a high altitude balloon based on a Raspberry Pi.
  2. Payload uses APRS and CW (Morse Code) for post-flight retrieval.
  3. Payload transmit SSTV (Slow Scan TV Images) in flight.
  4. Raspberry Pi Camera module to store images on SD card for retrieval after recovery.
  5. Payload is packaged in a lightweight insulating container.
  6. Payload designed for nichrome cut-down mechanism with balloon burst as a backup.
  7. Onboard microcontroller (or Raspberry Pi) drives the nichrome cutdown mechanism.
  8. Cutdown is time based, and also potentially distance based, to limit distance from launch.
  9. CARC will provide the APRS/CW beacon.

Budget - HAB Mk1 (Priority One)

Item Estimated Cost
Latex Weather Balloon $25
Bottle of H2, filling gear (Assuming half bottle, not including bottle and regulator) $45
Raspberry Pi $42
Raspberry Pi Camera Module $30
SSTV Module $80
Baofang UV5R Radio $30
AAA Batteries (16 count includes testing) $27
36" Parachute $25
Payload radio cabling Donated by CARC
Ursus Minimus Tracking Donated by CARC
Microcontroller and cutdown technology Donated by CARC
Foam for recovery package Donated by CARC
Total: $304

Payload Weight Budget

Item Weight (grams)
Raspberry Pi 50
Camera Module 3
Easy Digi 20
Radio 220
Batteries - (3) AA 45
Microcontroller board 20
Payload container 100
Ursus Minimus 12
Parachute 68
Cutdown mechanism 20
Total (730 max) 656

Payload notes

  • Parachute size calculator suggests a 36“ parachute for a 500g payload for 4mps descent rate.
  • UV5R radio weight includes battery.

SSTV Receiver (Priority One)

  • Receive, assemble, display images live.

Deliverables - SSTV Receiver (Priority One)

  1. A receiver capable of rendering received SSTV images and storing them.
  2. Optionally upload these images to a live web presence during the flight.
  3. We can use MMSSTV on Windows to receive images.

Budget - SSTV Receiver (Priority One)

Item Estimated Cost
USB Sound Card for SSTV Receiver $14
Sound card interface for SSTV Receiver $10
Laptop for SSTV Receiver Borrow
Radio for SSTV Receiver Borrow

Balloon APRS tracking/Recovery (Priority One)

  • Equipment necessary to monitor and track APRS transmissions from the balloon while in-flight.

Deliverables - Balloon APRS tracking/Recovery (Priority One)

  1. Vehicles equipped with APRS tracking radios and laptops/mapping.

Budget - Balloon APRS tracking/Recovery (Priority One)

Item Estimated Cost
APRS Tracking setup - radio, laptop, etc CARC members

Yagi Build (Priority Two)

Deliverables - Yagi Build (Priority Two)

  1. Yagi antennas for use in payload recovery.
  2. We'll also need

Budget - Yagi Build (Priority Two)

Item Estimated Cost
BNC connector hardware $20
Antenna elements Donated
Antenna body Donated

Offset Attenuator Build (Priority Two)

  • Build an offset attenuator to go with the Yagi above!

Real time mission web presence (Priority Three)

  • APRS mapping - payload and foxhunters
  • SSTV images

Deliverables - Real time mission web presence (Priority Three)

  1. Web presence with real-time data collection.
  2. APRS data ( links?)
  3. Chase vehicles
  4. SSTV images
  5. Other content?

Budget - Real time mission web presence (Priority Three)

Item Estimated Cost
Web server Donated by KC2WAC

Trajectory / Burst / Landing forecast (Priority Three)

  • Finds best resources available for forecasting balloon trajectory.
  • Provides recommendation to launch team for initial balloon volume / free lift, based on predictions, to produce a reasonable flight.
  • Potentially integrates with real time mission web presence.

Doppler Build (Priority Three)

As we mount more balloon missions, it would be beneficial to have a fixed doppler station for DF purposes. That way, even with only one mobile bearing we might be able to triangulate. This will also be a useful addition to foxhunts.

There are several kits for building DF dopplers, the most popular of which seems to be the PicoDopp. Other doppler kits are approximately the same cost and complexity, so the total parts bill would be approximately $200.

We can install a 2m and 70cm doppler array on the roof of Barton and put it on the internet for remote usage.

Budget - Doppler Build (Priority Three)

Item Estimated Cost
PicoDopp Kit $169
Antenna hardware $50
Total $219
Last modified:: 2014/05/05 15:06