it isn’t as complicated as it looks – just a clock which keeps accurate time and sets itself. (An Arduino is a miniature computer – it is as powerful as the computers we had 30 years ago but the entire circuit board will fit into a cigarette packet).
There is a big transmitter tower at Anthorn in Cumbria which transmits a signal every second at 60 KHz. The signal has a callsign MSF (Mike Sierra Foxtrot) as it can be picked up in foreign countries, and M (Mike) means “United Kingdom” on radio callsigns
The Germans have a similar one DCF77 (Delta Charlie Foxtrot 77) – D (Delta) means “Deutschland” as you would expect. But I want the correct British time, as it is an average between the atomic clock and the rotation of the Earth, as the Earth is actually slightly on the wonk (it rotates at an angle) meaning that extra leap seconds need to be added into the time every few years.
The circuit board in the clear plastic box picks this signal up, and produces a pulse of electricity every second. This pulse varies in length and format depending on whether its a new minute, and there are other signals encoded into the pulse (by switching parts of the signal on and off, like old style morse code.)
So when a whole minute has been picked up by the software, we have the correct time and can display it.
In fact I borrowed the code from this dude as my programming skills aren’t that good
MSL radio time receiver code for Arduino
(I dropped out of uni after year 2, was more interested in MDMA :laugh_at:) so I am having to relearn such stuff. I just added the bits to make the LCD display work.
As I said its actually complete overkill for a clock – you can buy similar clocks in the shops, its just that I was curious about how the system worked, had the equipment to decode it and wanted to practice my programming and electronics as this had got rusty – a few years ago I was doing much more complex electronic stuff than this…
it was a interesting challenge, and in my field of work an accurate clock is always useful…
