Introduction: 16x2 LCD Shield for Arduino Uno Using 3 Wires

Picture of 16x2 LCD Shield for Arduino Uno Using 3 Wires

I take no credit what so ever for this sketch. It has been copied from

On the hardware design side of the original instructable however, I noticed a small flaw.

If you were to follow the the diagrams posted on there, there is a minor flaw in one of the drawings when compared to the other reference diagrams. I have highlighted this in the comments section of that instructable. For easy reference a corrected diagram is also attached here.

Step 1: The Sketch

Step 2: Some Minor Changes

Picture of Some Minor Changes

A minor correction to the diagram on the original instructable

I would also recommend removing the NPN transistor and merely hooking up a 1 kohm resistor across the appropriate pins for the back light (if turning on and off is not a required option).

Overall, although it took me a couple of long hours to get this soldered and up and running, it was very satisfying in the end and all it cost me to make the shield was US $2. The number of digital IO lines it frees up is not small and should be reason enough for someone to consider making this.


dav33 (author)2017-11-04

For me it doesn't work with your minor change (fuzzy characters are displayed). When I put Arduino pin 7 on IC pin 15 (like on the original sketch you mention at the begin) then text appears correctly

About This Instructable




Bio: An avionics engineer by profession. I am a huge DIY freak and my proudest possessions are my tools. Since 2016, I have been interested in ... More »
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