Schematics and files for my LCD controller for Printrboard

As promised yesterday, I have bundled up a zip with all the files needed to have your own board manufactured.

The zip includes the following:

This PNG file showing what the finished product should look like.

The 9 Gerber files required for construction.










And the Schematic in pdf form.


Enjoy!! And if you build one, let me know…

NOTE: The rotary encoder layout on the board is for the wider version as sold by Sparkfun electronics. The footprint will also work for the more common narrow device, all you have to do is bend the large legs a bit.

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28 Responses to Schematics and files for my LCD controller for Printrboard

  1. Nick says:

    I’m trying to get this hooked up to a rev D and a rev F6 and I’m getting the same thing with both. Black bars across lines one and three. I’ve tried splitting up the lines between EXP1 and EXP2 as per instructions (same wiring just different connections to the board). If anyone has any suggestions I’d be happy to hear them!

    • Rick_S says:

      Hello Nick,

      I apologize for the terribly long delay to respond and approve your comment. I’ve been terribly lax about checking it and didn’t realize I had some activity. To answer your questions, the way I have my display wired is how the original Printrboard display was wired. The standard firmware in the Rev D & F boards that I have tried all worked with the exception of the most recent which they never posted the source for so I couldn’t verify why. So if you have a board with Printrboard OEM firmware that has not been updated to the most recent they have, it should operate the display, rotary encoder, and reset when wired as I have shown. The link you provided for the Panelolu also incorporates SD support by changing the firmware via a non OEM branch. While I’m sure this would work as they show, I haven’t pursued it as I try to stick to the OEM branch as much as possible.


      • Edward Crutchley says:

        It is most likely because of the new LED’s Printrbot started selling. It uses one of the signal pins that is used for the LCD adapter cable. I don’t know why they didn’t use the other expansion header, or release the source code. I left a message with Brook on Google+, but no reply!

        • Rick_S says:

          I didn’t try Brook directly, but did try their support board with no answers. Not a huge deal, but it would have been nice to see what they did to kill the LCD support in the most recent firmware. Your thoughts of the LED strip could be correct.

          I’d almost like to try out their G2 board, but I really don’t want to shell out another $100 Plus shipping to get it when my F5 is working just fine.

          • Edward Crutchley says:

            I would hold off on that if you use the heated bed. For some reason it isn’t compatible with the old one and the Pro’s heated bed hasn’t been released yet. I wish Brooke would release more files, but the guy that designed the printrhub put out a lot of interesting info
            Hopefully the firmware will be up before long, I’m pretty curious myself.

  2. Ed says:

    I’m waiting on the proper rotary encoder. It’s hard to afford parts on a disability budget, $700/month doesn’t go very far.

    • Rick_S says:

      I would imagine it is. Once you get your proper parts, let me know how it went. It’s been a while since I built my display and It’s good to hear from people who benefited from my project.

      Good luck and if you have any other questions, let me know.


      • Ed says:

        I received the rotary encoder yesterday and was able to get it working. I think I know what went wrong the first try. The schematic you have available did not show which pin was 1 and which was 16 on the lcd. I’m pretty sure I wired the display backwards and used the wrong value capacitor (completely my fault, dirty computer screen). I had to use the pictures of it assembled, just for reference. Thanks for making these files available, but you may want to update the files and number the pins on the schematic.

        • Rick_S says:

          I labeled the board with the pin numbers. The schematic doesn’t show pin numbers mainly because the part I used for the LCD in the schematic builder only had the signal names which is the most important part for the schematic. A “Standard” LCD has all these signals in specific locations, but if someone were to use the schematic with a non standard display, as long as they tied the signals to the appropriate place, it should still work.

          However, your point is taken, and I will see if I can edit the standard display in my schematic or at least indicate a pin 1 position to prevent other people from reading it backward.

          I’m glad you got it going.


          — Update, I have edited the schematic to show pin 1 position on the LCD part. Hopefully this will avoid any possible confusion on wiring up the LCD.

  3. Ed says:

    No, worries! I like trying to fix broken electronics anyways. I was thinking about trying a different board for a while now.

  4. Ed says:

    I was pretty cautious in wiring, but the wiring diagram I used had the rotary encoder ground line reversed. I didn’t notice until I pulled the datasheet trying to learn the differences between different rotary encoders. I’m not too worried,if I do damage it, it will just be another project to fry to fix. I’m going to order another board anyway, maybe ramps. I haven’t made up my mind yet.

    • Rick_S says:

      It’s funny you say that, I actually did purchase a spare printrboard as insurance against me mucking something up when I was in my experimentation stages with this printer. The main reason I wanted to build an LCD was the cost factor. I already had 90% of the parts to build it lying around and based on Printrbots photos of their official LCD at the time I knew I could build it for much less money than they wanted. BTW, did you get your display working??

  5. Jayson Peabody says:

    Hi Rick
    I cam across your blog and loved the posts about the LCD controller. I used your schematic and wired up one using an encoder from sparkfun and a 4x 20 lcd display from them as well. When I fire it up the display shows a bunch of gerbrish, it looks like alien symbols. They do move when I click the encoder button. Checked the 14 pin cable, wiring etc no fix. Would you possibly have any insight? I would appreciate your help.
    regards, Jayson

    • Rick_S says:

      Gibberish on the display could be an indicator of the data getting corrupted or noisy power. You could try adding some filter capacitors between your power and ground connections near the LCD just to make sure you have clean power. You could try different cables. While I’ve never purchased a 4×20 from Sparkfun, I see no reason why their basic 4×20 wouldn’t work. I’m guessing you purchased their “Basic 20×4 Character LCD”. You could also try different wires just to make sure you don’t have a flakey wire. Maybe disconnect all the wires then re-wire one at a time to make sure all is good. Depending on the length of your wires, you may try some shorter ones, too much length may cause a problem with signal loss or picking up electronic “noise” from the printer motor and electronics.

      Good luck,


      • Ed says:

        What length wire did you use?

        • Rick_S says:

          If that question was directed to me, I used a section from an old monitor cable about 16″ long. I used crimp on fittings to put the ends on the cable. This setup has worked well for me since I built it.


          • Ed says:

            Thanks, just trouble shooting mine. I made a few simple mistakes, like using the wrong rotary encoder and resistor. I think I might have a ground line reversed, mine just shuts the board off. I don’t think the wrong type of encoder would cause that, what I wouldn’t give for an oscilloscope!

          • Rick_S says:


            That sounds like you have a direct short somewhere if it completely shuts down your printrboard. Please be very cautious in your wiring, I’d hate to see you accidentally damage your printers board.


        • Jayson Peabody says:

          I used a 3 inch piece of hard drive ribbon cable to go from the board to display. The display problem I was having was due to my switching of one of the data lines. After re bread boarding the circuit all was well.

  6. Lucio says:

    Thanks for your work.
    I also ordered some PCB and they are working flawlessly.
    I was wondering if the files you posted are editable and with what software?
    I would like to try different things like reduce the size of the pcb or other features.


    • Rick_S says:

      Do you have a photo of your board working?? I’d love to see it if you do. As for editable files, I did the original file in Eagle. I recently had to re-install the OS on my computer and I lost some of the work I’d done in the past. I’ll have to see if I can find that schematic and board file for the LCD controller. If I do, I’ll look into publishing them. Remember though if I find them, these files are licensed under CC non commercial. So use and tweak all you want for yourself and others, just retain the legacy and don’t try to sell them.

      If I can’t find them thought, this is a very simple circuit. I did post the schematic in pdf format that you could easily duplicate in eagle and have a board design of your own.


  7. Hunter Halcomb says:

    Hey Rick, I don’t see the rotary encoder you have on SparkFun. Maybe they don’t carry it anymore. Any idea if be an acceptable substitute?

  8. Hi,

    thank you very much for your awesome work. I used your files to order a few PCBs. And it works great. I just need one of the PCBs, so I have 9 left. If you are interested in these, or if any of your users is asking for a PCB, you are welcome to contact me. I don’t want to make any money with them, but I will send them out to anyone who will pay the shipping costs.


    • Rick_S says:

      Thanks so much for the compliment. I don’t know if you saw it or not, but I have also posted a full case that can be printed to house the LCD. It is on Thingiverse –Here–. If anyone reading this is interested, comment here and I will forward the email address you enter for the comment to Phillip. The transaction will be totally between Phillip and you. Phillip, if there are takers and you do run out of your boards, please post so I will stop forwarding messages to you. I’m assuming the email you entered is valid. Also, if you do finish your build, please post a photo on thingiverse or post a comment here. I’d love to see it.


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