Today I upgraded my Adafruit Ice Tube clock with a GPS module. The clock is beautiful but I found myself frustrated by having to continually update the time as the clock would slowly get out of sync. Fortunately, there is a handy guide on how to add a GPS module to the clock so that it can readjust the time based on GPS. It only took a few minutes to do the entire upgrade.
For the GPS module, you can use any 5 volt GPS module with 4800 baud TTL NMEA output. I chose the Parallax PMB-648 as it is relatively low cost and fits the specification perfectly. Once you have the GPS, it’s merely a question of disassembling the clock and soldering the GPS to the clock.
The next step is to reprogram the clock with the new firmware. You will need a 6 pin AVR programmer for this. I used Adafruit’s USBtinyISP AVR programmer. Make sure you have AVRDUDE set up correctly. With the correct environment, it is simply an issue of pushing the new firmware that supports GPS timekeeping.
And that’s it. Just reassemble the clock and case and you are done. It was really cool to turn the clock back on and have it automatically adjust to the correct time. Now I don’t have to keep resetting the clock 🙂