Balloon TV

All done and ready to go, check the project diary.

This is a little project for adding an ATTiny 85 to a Commtech Video transmitter in order to get it to transmit it on 1252MHz, and send out a CW (morse code) identifier on the audio channels. The transmitter is a quick and simple solution for the annual Dutch Balloon Fox Hunt called Landelijke Ballonvossenjacht

• The development guide gives you information on how to build your own version of this project.
• The datasheets directory contains all the data sheets and schematics I used to figure this out.
• The antenna is a simple .

A brief timeline with notes and funny stories can be found in the project diary. I'll try to keep it updated with the latest info as much as possible.

TODO list

In order of importance:

• Create Arduino code for setting the frequency of the Comtech transmitter (using I2C to program the SP5055).
• Create code for sending CW (morse code) over the audio channel of the Comtech.
• Add microcontroler inside the comtech enclosure
• Add SPI connector for external programming
• Create lightweight cloverleaf antenna
• Connect and test Video signal (send/receive)
• Add output amplifier to the Comtech to create approx. 1.5 Watts of output power.
• Make the whole setup water-proof.

Ideas and nice to haves (expected to be implemented for the 2017 version of the ATV transmitter)

• Video text overlay with callsign (and other info?). I2C teletext ICs are available for this.
• Temperature inside/outside as text overlay. I2C temperature sensor.
• Add the audio of the voice transponder in the balloon to the audio channels of the video.

The resulting transmitter before closing it up:

The transmitter and the antenna, ready to go into the balloon's pod:

And the image of the I2C communication between the ATTiny and the SP5055: