Introduction: Assembling the LCD117 Kit

About: Father of two active toddlers desperately trying to find the time to build every interesting project from Instructables. Slowly training the kids to love building things. The wife? She thinks we are all crazy.…
This boards turns any (HD44780-compatible) LCD into a serial LCD. The kit is available from and allows a LCD to be controlled by an arduino or clone with only 3 wires.

Step 1: Resist!

Mount a 10K resistor. The color codes are Brown Black Orange.

Step 2: Resist Some More...

Mount the 330 Ohm resistor. The colors are Orange Orange Brown.

Step 3: Only One Direction

The diode can only function if placed correctly. Match the silver band on the diode with the band mark on the board.

Step 4: The Capacitor

Mount the monolithic capacitor. Orientation does not matter.

Step 5: Switches

Mount the switches. These will snap into the board in the correct orientation. If they don't seem to fit, turn 90 degrees and try again.

Step 6: Trimpot

Mount the variable resistor. This is where you will adjust the contrast of the display text.

Step 7: Power Regulator

Mount the TIP 120. I find it easiest to bend the leads 90 degrees and then solder. Make sure the heat sink (metal) part is towards the board.

Step 8: Socket to Me

The IC socket should be mounted with the notch towards the variable resistor. Solder in two pins on opposite corners and then check the positioning. Finish up soldering when everything is where it should be.

Step 9: What Next?

Now you need to decide which backlight resistor is needed for the display you have. If you have one of the displays from this is pretty easy. If you have a different display, see here to determine the resistor value needed.

For the 2x16 Blue display, use a 28 Ohm resistor (Red Gray Black).

For the 4x20 Blue display, use a 33 Ohm resistor (Orange Orange Black)

Place this resistor in the spot marked Rbl.

Step 10: The Headers

Solder in the headers which will match your display. The 2x16 and 4x20 displays I have both use the single line of headers at the top of the board. A double line of headers can be connected to the right side of the board if needed.

Solder in the pins at each end and then check for alignment before soldering the remaining pins.

Step 11: More Headers

These are the headers that go to the arduino. Solder in the 90 degree male headers provided.

Step 12: Easily Overlooked

If you plan on powering the display via the arduino, as most people will, you need to place a jumper as shown in the picture below. This changes the power feed from the Vbl pin to the 5v pin. I simply used a cut off lead as a jumper from the hole to the resistor lead.

Step 13: The IC

Place the chip in the socket with the notch towards the variable resistor. You will likely need to, carefully, bend the leads to get it to fit the socket.

Step 14: A Display, Mate

If your display doesn't already have a set of headers installed, now is a good time to put them in.

Step 15: Plug It In

Plug your board into the display and, using the cable provided, connect the board to the arduino.

On the display end, the black wire should connect to the Ground pin. On the arduino end, I preferred to connect to the A0, 5v, and Ground pins on the Bare Bones Board.

Step 16: Testing and Support and Programming

Testing Procedure:

Turn the trimpot fully clockwise (you may wish to turn it back a hair later).

Press the op test button and hold - then press and release reset - finally release the op test.
That should print the character set with the backlight on. The characters may wrap in an odd manner depending on the geometry of your LCD.

The reset button will print the custom characters while flashing the backlight for one second.

Both the LCD geometry settings and backlight brightness are under software control, so the backlight will stay off until turned on by a software command. See the phanderson command set, and the software demo, at for more information.

If you're using a Basic Stamp you can find code at

From here, simply program the arduino with the appropriate demo sketch found at the bottom of this page. You will likely need to change the sketch to reflect your communication pin choice.

The display should start shortly after programming is complete. Adjust the variable resistor until you are happy with the display contrast.

Much more information on programming the display and forum support are found at