Hey! Good work in the field of 8051 dev... I've managed to make a digital energy meter with a 3 digit multiplexed display... The most thrilling part is that I've done every square millimeter by myself:) - like my first project - the buzzer. Only this one's a lil more complicated. And I don't code in C. I prefer VB, and if I cant use that, I code directly in Assembly.

The 2 circles you see to the left is the disc that simulates the disc inside an actual energy meter. The red circle is the mount for the opto-coupler. The Main PCB (printed circuit board) was designed and made by me. Even the tracks are hand drawn (u can tell by the resemblance to my ugly handwriting:)... Within it, the 8051 is to the left, a decoder/driver IC to its right and of course the (3 digit) display.

 

You will notice that without the jumper (that lil black thingie to the left of the display board) it shows 001 - that is the no of units of electricity... Tariff is at the rate of Re 1.1 for the first 10 units (this is so I can demo it real time - a simply modif. of program would change that). This is to demonstrate how slabs for tariff can be implemented as well. Rate is shown when the jumper is put back in.

 

Proof of this u will see in the 2nd set of pictures. The tariff is now Re 1.20. the no of units is 12 and the rate is 14.2 (and 14.2 is NOT a multiple of 1.1) All this i thought id do in a couple of days... well its taken me a solid month of running around drivin' myself NUTS... but that's pretty much cause there were so many things I was learning... besides I did have a submarine to build as well:)