Jeff Geerling recently posted on Level 2 Jeff about a GPS clock from Mitxela. This reminded me of a project I did in the early days of the first COVID lockdown. I dug it and it still works. After powering on, it took around 60 seconds to find a signal and display the time - not bad for being in a box for 5 years.
Here’s a basic diagram showing the connections. I used an Arduino Nano and a UBlox NEO-M8N-0-10 GPS receiver. The UBlox is connected to the Nano’s hardware serial port, the synchronisation pulse to pin D2, and the MAX7219 8 x 7-segment display to the Nano’s SPI interface.
The time pulse function can be configured using the UBX-CFG-TP5 message. I configured a 100Hz pulse to be handled by the interrupt service routine to increment the time in centiseconds. Furthermore, I configured a UBX-TIM-TP time stamp message to be generated 10 times per second. After the time stamp message is sent on the serial port, the next pulse indicates that the time should be set.
