Picture of Multimeter Clock
The Multimeter Clock consists of three multimeters, the first meter displays hours, the second displays minutes and the last displays seconds. A 16F628A PIC microcontroller keeps track of time and outputs a calculated current to each meter to display the current time.

Get your own Multimeter Clock Kit here.
See Multimeter Clock project page here.

Step 1: How it Works

Picture of How it Works
The user enters the time by pressing three time adjust buttons. The first button increments the hours, the second button increments the minutes and the third button resets the seconds. Once the time has been entered the microcontroller will keep track of time from there. An interrupt fires every 10th of a second to increment a 10th second counter. Another routine checks to see if we have at least one full second of time, if we do the current time is incremented by a second.

The microcontroller has a separate output for each of the three meters. The meters are all in 0.5 DCmA mode, the negative lead of each meter is grounded and the positive leads are connected to a microcontroller output via a current limiting resistor. The resistor in this case is a 4.7K however this can be adjusted depending on the meter current scale available. Keep in mind that the PIC can deliver a maximum of 25mA to each meter so a meter with a lowest setting above 25mA would not work without additional circuitry.
frikkie9 months ago


hanndoddi1 year ago

This is a fantastic project nice job :)

Q: why are you using two chip sockets?(see step 2 photos)

mikerosati2 years ago
Great idea - I'm going to give this one a go as well..
I second in asking what software was used to draw up the schematic..
taylorglenn3 years ago
What software did you use to draw this schematic?
ynze3 years ago
Owww, wonderful idea, great build! Thumbs up!
WhiteTech3 years ago
Hey, Excuse the noobish question, but your setting is .5 mA, so the max, when it's set on it, is .5 mA showing on the scale?

I have access to ammeters that have a non-changible scale that goes to 20 mA, can the kit run this?
What a great idee!
abbtech (author)  signalelektronik4 years ago
Dr.Bill5 years ago
this is too cool
Why does the first meter say sunMa while the others are sunWa?
abbtech (author)  Wroger-Wroger3 years ago
LOL, I never noticed that before. I am thinking that the 2nd and 3rd are SunMa knockoffs. :)
abbtech (author)  Toastalicious5 years ago
LOL. I never noticed that before! That represents the quality of these meters I got, I should have spent more money on them. :)
Kasm279 abbtech5 years ago
I have one just like it except the colors around the dial are white, green, and red. Also, mine says MODEL instead of Sun(W/M)A, but it does say "YX-1000A" on it...
canida5 years ago
Nice project! Excellent work.
abbtech (author)  canida5 years ago
Thanks. :)
twocvbloke5 years ago
That's a pretty cool device, I'm sure the steampunk sorts would love to make a version of it somehow, but as it is, I like it... :)