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Multimeter Backlit LCD Mod

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Hello Instructables. I have wanted to join this amazing community for a long time and I am happy that I finally did!

In this instructable I am going to show you how to convert your standart multimeter's LCD into a baclkit LCD. We will use some LEDs and some clever programming to modify our stock multimeter. Thus, we will design a better product and most important we'll help ourselves do measurements in dark places!

The high-end multimeters have this function built in, unfortulantely not all of the affordable ones have it. It is handy to use the LCD backlighting sometimes, so lets just do it.


Compatibility?

Not a problem I think - all electronic devices that have LCDs have pretty much same looking display components, if you wonder where it will work or not, just open the multimeter to see, it is straight forward.

HOW?

I wanted to design the whole thing as it would be in a real off-shelf device.

After the modification there are no hanging wires and swithes, no messy batteries around.

When you press one of the standard multimeter's buttons - the yellow one in my case - and  voila the LCD is lightende for 15 seconds! And what is more cool - you can program the 15 seconds delay to your preferences and change it to one minute for example!

INEXPENSIVE?

Yes!

HARD TO DO?

I'd say a bit tricky.
 
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Step 1: Parts List & Tools

Picture of Parts List & Tools
All parts you need are:

> SMD LEDs x 2 (Mine are tiny! 1.6mm (L) x 0.8mm (W) x 0.8mm (H))
> ATtiny85 microcontroller
> Cables 


Tools:

> Screwdriver
> Soldering iron and wire
> Super glue
> Heat shrink tubes
> PC & Arduino Uno to program the microcontroler

Step 2: Open The Multimeter

Picture of Open The Multimeter
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Not much to say here.

Grab a screwdriver and open the multimeter. Remove the battery cover, the batteries, the back shell and then detach the PCB from the front shell. Take the LCD plastic frame out.
Great instructions!
kukubee (author)  electronic.ebonics1 year ago
Thanks for the feedback. I appreciate that!
Gabse1 year ago
I made something like that whit my Soldering Iron
kukubee (author)  Gabse1 year ago
Yeah, great idea!
Gabse kukubee1 year ago
Thanks
Gelfling61 year ago
Excellent!!! I have a Fluke meter I salvaged years ago, and just recently (within a month) bought a bunch of 5mm While LED's. This would be perfect for the times I can't quite read the meter because it was at a bad angle, or in a shadow where I couldn't read it because of the low lighting. Now, to figure the resister value... (they're 3.3V 5MM LED's, the meter runs on a single 9V transistor battery. So... 4 LED's in series wouldn't be out of the question.) Thanks for the inspiration!
kukubee (author)  Gelfling61 year ago
Yes, try with 4 LEDs in series. If it is too bright a 100-200 Ohms resistor in series with the LEDs would be fine.
Your photos are fantastic. :D
kukubee (author)  jessyratfink1 year ago
Thanks a lot!