Project Horus High altitude balloon project


New board update

My GPS modules have arrived & I've dropped one into my Nut board. I've also written most of the code needed to get the FSA03 working correctly, many thanks to junderwood for helping me with the UBX protocol. I'll try to get some more testing done soon & put up schematics/instructions asap :) .

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New board build

I had a chance to etch and test my first board with the new design. The board itself seems to be working fine, though I haven't got a radio module or GPS on it at this stage - they're still in the mail on their way to me.

I tired dyeing the board using some permanent markers, which did not work so well. Next I'll be trying red fabric dye, which from what I can tell should have better results.

The cost per board works out to around the $100 (AUD) mark:

  • PCB substrate: ~$1
  • ATMega328P: $5
  • LM3940: $1.50
  • Temp sensor: $5
  • Passives: ~$1
  • FSA03 GPS module: $60
  • NTX2 25mW Module: $30

Total: ~$103.50

Edit: The fabric dye worked a treat!

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Current state of affairs

As is evident by the number of recent blog posts, Project Horus has seen a bit of an unplanned hiatus over the last few months - both myself and Adrian VK5ZSN have been kept busy by real world commitments of one kind or another. The project has not been abandoned, and we're hoping to launch again soon - initially I'd like to re-fly Horus 2 (telemetry baud rate experiment).

There have been a few new developments of late:

New flight computer (Nut 1.0):

I've received several emails asking me if I had any spare Isis boards for sale, or any other boards which were 'ready to go'. I don't have have any boards on hand, but I've been working on a design for a board which implements a whole balloon tracker & can be etched at home on single sided copper clad without any fancy equipment.

The single sided board

I've not yet made up a full board & tested it yet - I'm waiting on components to arrive at this stage, but should have a complete board ready this week. Once this is tested & I'm confident it's up to scratch, I'll be posting the full schematic and board layout, as well as a step by step guide on how to etch, populate & program the board yourself.

Balloon-borne simplex repeater:

Adrian VK5ZSN is working on a simplex repeater to be flown on an upcoming balloon flight. This is being built around a 2M FM transceiver, a sound recording IC & a PIC for control & logic. The repeater will accept incoming transmissions of upto 60 seconds, which will then be re-broadcast from the balloon. At apogee, we should be able to make contacts within a 500km radius (or so) of the balloon!

Eventually we'd like to fly a true duplex repeater - this would give us an excellent communications platform whilst chasing the balloon.


I've improved the carputer somewhat - it's no longer broadcasting an ad-hoc Wi-Fi network, rather it sports a WRT54G powered by the computer''s internal 12v supply. This allows for much greater range & far better throughput. The carputer also has a new GPS module - a SIRFIII based module, which is much more sensitive than the previous module which often took several minutes to gain lock.

More updates soon (I promise). :)

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