Quick Project – Arduino Backlit LCD shield

In this tutorial learn how to make your own backlit-LCD Arduino shield.

Updated 18/03/2013

Let’s see how simple it is to make your own Arduino LCD shield. Sure – you can just buy one, but where’s the fun in that?

Getting Started

Our LCD is a two line, sixteen character backlit LCD. It has a typical HD44780-compatible interface, which makes it very easy to use with Arduino. The other parts required are laid out along with the LCD:3

partsss

We have the LCD, a Freetronics Protoshield Basic, a button, a 0.1 uF capacitor and some header pins. We also need some solid core, thin wire to make jumpers.

Next is the plan – our schematic. Even for the smaller projects, this is a wise step. You can iron out the bugs before soldering. From experience with these backlit LCDs, there are two ways to wire them up. Either with a trimpot so you can adjust the display contrast, or without. With my example screen, the display was only clear with the trimpot turned all the way to one side, however your screen may vary.

Please note that the voltage for LCD backlights can vary, some are 5V, some are 3.3V. Check your data sheet and plan accordingly!

Consider the following schematics:

schembss1

and

If you are making this circuit without the protoshield, the 0.1 uF capacitor is for decoupling, so place it between 5V and GND. It would be wise to test your LCD using the setup on pin 3 as shown in the second schematic. Then you will have a good idea about the display brightness and contrast. This was done with the usual breadboard setup, but not before soldering the pins into the LCD:

lcdpinsss

which allowed the LCD to slot into the breadboard nicely:

breadboardss

The brightness shown in the image above is satisfactory, so I measured the resistance between each of the outside pins of the trimpot and the centre. The resulting resistance between the centre and ground was around 15 ohms, so basically nothing. So for this LCD, there will not be any adjustments – and the full schematic above will be used (with LCD pin 3 going straight to GND).

The sketch to drive this LCD is quite simple, for example this will do:

For more information about using LCD modules with your Arduino, please refer to my series of Arduino tutorials.

The next step is to consider the plan for the shield. Thankfully this is a pretty simple operation, and minimal extra components to worry about. There is a catch with regards to the LCD module itself, it has six large metal tabs that need to be avoided if the LCD is to sit flush on the shield:

tabsss

Kudos to the engineers who had the pinouts printed on the back of the LCD. Thanks!

You can see that one of the tabs has been … removed. Just carefull use a pair of pliers and bend it slowly back and forth. Metal fatigue will take care of the rest. Anyhow, back to the shield. It is a simple task of soldering in some jumper wires to connect LCD pins 4, 6, 11~14 to the Arduino digital pins 4~9:

linksss

Also during this stage the reset button and the 0.1 uF capacitor were soldered in. When fitting the capacitor, leave around 5mm of length above the board, so you can push it over to one side, this is to give the LCD enough clearance. Furthermore, the lead from the 3.3V pad to LCD 15 is curved so as to avoid another metal tab on the rear of the LCD. The underside of the shield is quite simple:

linskrearss

To ensure a good solder joint when working with these shields – it is very important to heat the ring around the hole for two seconds if you need to create a solder bridge, or heat the wire for two seconds before attempting to solder it on. Otherwise you will either get a cold joint; or become frustrated and keep adding solder, at which point it leaks through to the other side and becomes a problem to remove.

Now to solder in the LCD. If you can, try and bend the LCD pins 1, 3, 5 and 16 towards the GND line, this will help when you need to connect them later. However, please be careful, if you position the LCD incorrectly you will have to basically start all over again with a new shield. When trimming the header pins, be sure to put a finger over the end to stop the cutting flying into your face:

lcdinss

Once you have the LCD module soldered in, and the ends trimmed – the final soldering task is to bridge the pins to the necessary points. This is relatively easy, just heat up one side of the junction and coax the solder across to the required spot. Sometimes the gap will be too large, so trim up the excess legs of the capacitor into small jumpers, say 3~4 mm long. You can then solder these in between the pads quite easily:

almostss

Now – the final soldering task. Snap off some header pins, two of six-pin, and two of eight-pin. Insert them into your Arduino or compatible board as such:

pinsinss

Then place your shield on top and solder the header pins to the shield. And we’re finished… well almost. Before you use the shield, use a multimeter or continuity tester to make sure none of the pins are shorted out, and generally double-check your soldering. You don’t want any mischievous short circuits ruining your new LCD or Arduino board.

Once you are satisfied, plug in your new shield and enjoy your success!

successss

So there you are, another useful Arduino shield ready for action. I hope you enjoyed reading about this project, and hopefully some of you have made one as well. High resolution images are available from flickr.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

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John Boxall

Founder, owner and managing editor of tronixstuff.com.

16 Responses to “Quick Project – Arduino Backlit LCD shield”

  1. Andy Gelme says:

    The drect approach … Arduno dgtal output pns drvng the LCD nput s smple, quck and supported by the standard, bundled LCD lbrary. However, t does use 6 dgtal output pns.

    If your project requres lots of dgtal pns, then you mght lke to consder usng just 3 Arduno dgtal pns and an 8-bt latch to drve the LCD.

    As follows … http://www.arduno.cc/playground/Code/LCD3wres

  2. hlantz says:

    Here’s a post I dd on the Adafrut forums of the Protoshelded verson: http://forums.adafrut.com/vewtopc.php?f=31&t=15940 . I have done up a proper Eagle schem/board and had a prototype fabbed after that but I need to make some small adjustments to the board desgn (manly modfyng the slkscreen and addng a second header opton) before releasng t; but t’s all based on the same desgn as n the post.

  3. hlantz says:

    To tag on – f you’re REALLY n a pn crunch, you can use a 74LS164 wth a smple AND gate to take the used pn total down to TWO wth the ShftRegLCD lbrary found on http://code.google.com/p/ardunoshftreglcd/ . You need that extra gate (whch can be constructed from a dode and a resstor), but you save a pn!

  4. Jamie Mackenzie says:

    John, the 0.1uF cap s not n the schematc. Does t just st between +5V and GND, or does t control some aspect of the LCD?

  5. Alastair says:

    I’d be nterested to see you do a project wth the bggest backlt LCD on the market. I’ve seen 4 dsplays. Do they come bgger (wthout gettng nto Pad terrtory!) than 4 rows?

    I’m wonderng f you could drve 2 rows to dsplay text at double heght for bgger text. Have to defne your own btmaps I guess, can specal chars be downloaded to the dsplay drver? I’d lke to make somethng that dsplays basc Track nfo and Playhead poston for an audo playback applcaton on a Headless MacMn. Bonus ponts for handlng nputs from a jog/shuttle knd of rew/fwd nput control (not a pot a sprng loaded dal) and nce play/pause momo button.

    • John Boxall says:

      Hello
      It would be a lot easer to just use a smaller LCD montor (you can get 5 and 7″ 16:9 ones wth VGA nput, get a mn-DVI adaptor) and have the audo software people take care of t. Hardware would be a fne, that stuff s already on the market
      cheers
      john

  6. Alastair says:

    Thanks John. The only problem wth an LCD s that at certan tmes my software s also outputtng a Vdeo sgnal (at other tmes t’s outputtng just audo n several languages).

    I’m not sure I can output to two separate dsplays (one for control dsplay) one for Vdeo Projector n the IDE I’m usng (Quartz Bulder made by Kneme to turn .qtz fles nto stand alone apps for OS X). Wll look nto t, t’s a good dea an I had wondered but never seen a 5″ LCD. A 5″ touchscreen (even B&W) would be deal actually!

    As for loadng custom btmaps as characters on ths project, s that possble?
    Are the btmaps currently beng used contaned n lbrary or the LCD tself? It wasn’t clear to me what data s beng sent to the LCD —ASCII or btmap.

    Thanks agan, even though I’m yet to by a starters kt, I love readng the projects featured on ths ste.

    What starters kt would you recommend? (I made a kt synth wth 1000s of components n the 80s but don’t really know that much about electroncs). I’m nterested n projects that can measure thngs lke temperature from multple ponts and log data. Also projects that can control envronmental thngs lke room lghtng and so on.

    • Alastair says:

      Oh I’m n Melbourne, AUST f that helps wth a kt recommendaton!

    • John Boxall says:

      Hello Alastar
      Yes, you can load custom btmaps onto the LCD, t s a real headache but can be done. But that’s my opnon! The data s stored n the sketch and sent to the LCD… have a look at the data sheet for any HD44780-nterface LCD module and you wll see how t works. If you were assemblng synths n the 80s ths wll be a doddle. Here s the lnk to an deal starter kt http://bt.ly/bw8Eyq plus you may want some other cheap components avalable from LBE or Altroncs, etc. Once you spend some tme tnkerng wth t you wll get a better dea of what to do. We have covered temperature measurement n tutoral chapter two, and also n the mcrosd sheld revew http://wp.me/pQmjR-lB
      have fun
      john

  7. CVBruce says:

    Cool! I’ll have to gve ths a try. Thanks

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