1. GPS-VTI by Tony Barry presented by Dave Gault

2. Overview minimal wiring (less than thirty wires to solder) no chips, transistors, or surface mount to solder. Just wires + LEDs + switch. doesn't need USB to function, can run off 12V DC based on Arduino AVR architecture (MEGA1280). uses Sparkfun breakout board for MAX7456 GPS is EM406A from USGlobalSat Add - two LEDs, one switch, two RCA sockets, a case and an afternoon to assemble code is open source released under Berkeley 3-clause software licence

3. The circuit diagram

4. The setup screen

5. The timing screen HHMMSS milliseconds Vsync period field counter field end

6. Summary Cost ~$100 and an afternoon with a soldering iron Cost ~$100 and an afternoon with a soldering iron Software to load the program into the microcontroller is free Software to load the program into the microcontroller is free Code is still in development, currently at beta v16 Code is still in development, currently at beta v16 Independent QA review is yet to be arranged Independent QA review is yet to be arranged Should have a second device ready for testing in the new year Should have a second device ready for testing in the new year usage is relatively simple. Connect to camera, monitor, 12V or USB port of laptop - power on Connect to camera, monitor, 12V or USB port of laptop - power on Switch to "Setup Switch to "Setup Wait for GPS fix (may take a few minutes) Wait for GPS fix (may take a few minutes) record observers site details record observers site details Switch to "Run" Switch to "Run" Wait for 10 seconds for the GPSs ZDA mode to start Wait for 10 seconds for the GPSs ZDA mode to start Record the occultation. Record the occultation.