Another clock? No. Not today. This is a Grid Frequency Meter. "What is one of those?" I hear you ask. Essentially, as the load on the electricity supply increases, the generators have to work harder, a bit like riding a bike uphill. This makes the generators slow down. The Grid Frequency meter measures the frequency (or the "speed") of the electricity supply and so can determine how hard the generators are working. This then indicates how much load (how many kettles are switched on) there is on the grid (national electricity supply) at any one time.
I had the PCB made to my design, with a rectangle milled out from the middle which is the exact (phew!) size of the LCD display. The LCD display can then fit neatly behind the circuit board while being visible through the cut out from the front. The picture taken from an angle makes the display look faded. It isn't, it is just that the LCD is not designed to be viewed from that much of an angle, it shows off the PCB well though! The close up picture is taken of the board once it was fitted into the case it was made for.
In the angled picture, the frequency shown is 50.01Hz, this is just off the nominal frequency of 50.00Hz and the bar graph is in the centre of the display. In the close up picture, everyone has finished boiling the kettle and there is too much supply, the generators are running too fast at 50.10Hz and the little bar graph has moved away from the centre of the display towards the right hand side.
This is a redesign of an old project. Originally written for a PicAxe microcontroller, the software has been rebuilt from the ground up for a similar PIC microcontroller using the wonderful Great Cow Basic. I took the opportunity to design a new circuit board where the printed circuit board is also the front panel with a window for the LCD.
The web page was made with Mobirise