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Ask Slashdot: Hobbyist-Ready LCD Touch Panel For Embedded Projects? 142

michael_cain writes "I've been asked (by family, friends) to consider several small embedded controller projects. A good starting point for all of them would be a backlit LCD graphics module with touch screen pre-mounted in a plastic enclosure with enough room behind the display for a custom circuit board. 320-by-240 pixels, 3.5 to 4.5 inch diagonal measure, monochrome is sufficient (but color is always cool), easily driven by an AVR or PIC type microcontroller. And priced at a reasonable point for a hobbyist! Anyone seen anything like this?"
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Ask Slashdot: Hobbyist-Ready LCD Touch Panel For Embedded Projects?

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  • by Anonymous Coward on Thursday May 24, 2012 @03:17PM (#40102449)

    2.8", touch screen, colour. /shrugs/

    • 'This TFT display is big (2.8" diagonal)'
      At least they don't say "cheap" or "low cost"at 70 bucks.

    • by v1 ( 525388 ) on Thursday May 24, 2012 @04:31PM (#40103417) Homepage Journal

      adafruit carries several kinds of screens in different sizes. They appear to be designed to work with cheaper cellphones. Refresh and io rates can be slow. You can either get the bare screens with plastic ribbon hanging on them or get them with a little controller board. Save yourself the headache and get one with a control board. Most of them include code to interface with Arduino and/or other hobby microcontrollers.

      The data transfer rates on those i/o boards usually aren't fast enough to support video. On some of them you can actually watch it refresh, it's like unpacking a gif on a computer 15 years ago. So they work better for simple interfaces and displaying text (without scrolling) than for images. But you can draw icons as long as you don't get carried away.

      The demo code is often not properly optimized either, so you can get more out of them if you are ready to roll up your sleeves and get to work on their "drivers". I was able to reduce full screen image render on one here from 2.8 seconds to 650ms by recoding the higher level io layer that was in the driver sketch. (didn't have to mess with the library)

      I haven't used the touch interfaces yet, but it does add an additional level of complexity with the programming and with the io pin requirements on your controller. If you are going to be rendering icons or images, insist on one that has a sd card adapter built onto the io board, otherwise you are going to need to get one of those separately also to load the images from, which will further add to the cost, complexity, and io pin requirements.

    • Try this one for $29: TFT 3.2" 320*240 With SD Touch Module (Arduino Compatible) []
    • by C_L_Lk ( 1049846 )

      Not sure how "industrial" OP wants to go but we use these in all of our control panels - the prices are size dependent, but the smaller ones are well under $100, the larger ones can run upwards of $400. There are several other lines they offer if this one doesn't do what you need: []

    • You might want to check out newhavendisplay their TFTs: [] Their interface chips aren't that expensive either. Documentation could be a bit better but considering the price most of their products are a pretty good deal.
  • android, beagle or arduino versions of what you need

  • by NEDHead ( 1651195 ) on Thursday May 24, 2012 @03:17PM (#40102455)

    says it all

    • Re:Old smart phone (Score:5, Informative)

      by LanMan04 ( 790429 ) on Thursday May 24, 2012 @03:51PM (#40102897)

      Yes, this is the way to go. Grab an older Android phone.

      Fuck micro-controllers, just write an app. It's got wifi, bluetooth, ethernet (I assume that can be done over USB easily), haptic feedback...what else do you want on a hobby board?

      • Re:Old smart phone (Score:5, Insightful)

        by TubeSteak ( 669689 ) on Thursday May 24, 2012 @04:24PM (#40103351) Journal

        ...what else do you want on a hobby board?

        The pleasure of doing something yourself?
        Hobbyists are more or less the same no matter their particular hobby.
        In the remote control world, I've come across guys who could pay for whatever they wanted,
        instead they spend their nights and weekends engineering designs and hand fabricating parts.

        Haven't you ever heard the expression that the journey is as important as the destination?

        • ...what else do you want on a hobby board?

          The pleasure of doing something yourself?

          Yes, but there are reasonable limits to that if you're serious about the project.

          To develop my own internet-accessible thermostat, irrigation system, house control, etc... I could put a $40 "hobbyist LCD" on an arduino and add another $40 for an ethernet shield. Or, I buy a 6" Linux ebook reader or a 7" under-powered -but already hacked- android tablet ($20 biglots or $50 bens-outlet) and put my arduino on the usb-port.

          Not only can I focus on the part I really want to develop, it also makes future re

      • Yes, this is the way to go. Grab an older Android phone.

        Fuck micro-controllers, just write an app. It's got wifi, bluetooth, ethernet (I assume that can be done over USB easily), haptic feedback...what else do you want on a hobby board?

        Yes the high level of a standard smart phone is very useful. Especially for human interface. And WiFi/BT/ENet/USB for communication with other high level devices.

        However, how many user programmable I/O pins does it have? How man AD converters? What if you want to read temperature probes or other analog devices? Or interface with other low level devices? Sure you could design a custom USB device to do that, but now you've defeated the convenience of using a smart phone.

        The hardware depends on the

    • Not recommended. (Score:5, Insightful)

      by gmarsh ( 839707 ) on Thursday May 24, 2012 @03:55PM (#40102933)

      There's a few issues with smartphone screens. Given enough effort you can make pretty much anything work, but here's what you'll be up against:

      - Knowing what all the pinouts/connectors/voltages/signal levels are.

      - Data format: Most of these screens require a proper graphics controller to drive them, capable of clocking RGB data out of a framebuffer into the panel at a pixel clock of several MHz. You might be able to do this with a PIC32, but your code will be blasting data at the panel 99% of the time. You're in the territory of ARM7/ARM9 processors with SDRAM hanging off them when you're making a bare RGB LCD panel work.

      - Power: You'll likely have to generate a backlight voltage, and possibly even bias voltages for the LCD panel itself. The LCD may also run at a different voltage node (3.3V or less) while your AVR might end up being 5.0V.

      - Touchscreen: Resistive touchscreen isn't too hard to manage. If it's a capacitive touchscreen you might be able to wire it up to an AVR and use their QTouch libraries to make it work. But I'll warn, prototyping a capacitive touch system can be an exercise in frustration - it's not bad when everything sits in one place on a PCB, but you can't breathe on an airwired capacitive touch system without screwing it up.

      Honestly, you're best off finding a "smart LCD" with a built-in controller, with a simple SPI/UART/8-bit-parallel/etc interface. Adafruit has an Arduino compatible one up on their site which might be a good starting point, I'm sure there'll be plenty of other suggestions posted here.

      Or hell, you're better off keeping the smartphone whole and finding a way to reprogram it to do what you want.

      • Or hell, you're better off keeping the smartphone whole and finding a way to reprogram it to do what you want.

        I think that's exactly what LanMan04 meant.

        Or are you the type of person who takes apart old Pentium IV machines and tries to make a space heater out of it?

        • I think that's exactly what LanMan04 meant.

          Or are you the type of person who takes apart old Pentium IV machines and tries to make a space heater out of it?

          You're right, why would one pull apart a Pentium IV machine to make a space heater when it's already a space heater?

        • by Jeng ( 926980 )

          It might have been what LanMan04 meant, but it does sound like the person is more interested in the build process rather than the end result.

          As such then if you recommend a device, it's probably going to be ripped apart and used for parts. Not that there is anything wrong with that.

      • Or hell, you're better off keeping the smartphone whole and finding a way to reprogram it to do what you want.

        Pretty sure this this exactly what was meant.

    • by na1led ( 1030470 )
      Install VNC on a cheap SmartPhone and display whatever you want remotely from another computer.
  • by Hognoxious ( 631665 ) on Thursday May 24, 2012 @03:19PM (#40102471) Homepage Journal

    Sounds like the kind of thing that people who build in-car systems would know about.

    • In-car LCD systems are pretty overpriced really. For my upgrade of my system I've been considering figuring out how the iPad drives it's display and then adapting something like that.

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  • by Matt_Bennett ( 79107 ) on Thursday May 24, 2012 @03:20PM (#40102481) Homepage Journal
    MikroElectronika [] has some for various microcontrollers- they don't have packaging, but the whole thing is pretty self contained. The link above is for Microchip PIC32, but there are a bunch of other microcontroller boards available from them.
  • Check out SparkFun or equivalent. I've also seen some on eBay for as little as $20. []
  • I am just starting to get into Arduino programming, and I see various sellers. I tend to be more interested in the 2.4 and 2.2" diagonal LCD, many of which have touch screens than the larger ones. Lets see: Adafruit has a 2.8" LCD + touchscreen for $40 (though it is on backorder); I see various ebay sellers (e4u2011, isecsv110, yyli666 are ones I've marked) have 2.4" displays + touchscreen + SD reader for $20.
  • by Stealth Dave ( 189726 ) on Thursday May 24, 2012 @03:30PM (#40102595) Homepage

    I've looked into something similar to use as a controller/receiver for a whole house audio system, and you may want to look at a cheap Android-based device, some of which can be had for less than $50. For that price you get a resistive touch screen at around 320x240, 8G storage, stereo output, 256M RAM, WiFi, USB and a Java-based OS with plenty of apps pre-built and a well established development community.

    For a small 4" device, Google "benss android". I was able to find half a dozen listings for this under $50. (Haven't tried it, though.) Also, Big Lots in the US regularly sells 7" refurb tablets for $70.

    - Stealth Dave

  • Amulet Technologies (Score:3, Informative)

    by Anonymous Coward on Thursday May 24, 2012 @03:30PM (#40102599)

    Amulet Displays allow you to separate the UI (dedicated UI chip w/ display) from the execution and run it via an event driven framework. You can code it or it has a drag and drop version.

  • by chill ( 34294 ) on Thursday May 24, 2012 @03:32PM (#40102623) Journal []

    They might be more expensive than you're looking for, but they have a nice selection.

  • by Anonymous Coward

    You want an Anglia PIC32 Springboard!

    I have no connection to them except being a happy customer. We used their kit with a little 3.7" display to develop an industrial control device and the project went smooth as silk.
    The examples they provide actually compile and work as-is (what a novelty), and the Microchip Graphics Library is as good as you'll get for free and doesn't have too many bugs while performing acceptably.

  • "easily driven by an AVR or PIC type microcontroller" ... Hmmmm ... the main feature of the HD44780-type alpha LCD is that it is a static device, containing its own memory. The content is scanned by the hardware on the interface board.

    If you want similar functionality with a mono or color big size LCD, you have to have something in the way between the AVR and the LCD itself that is going to retain a display memory so that the LCD can be continually refreshed (and don't try to do that with an AVR). You co
  • We embed these in our Atom-driven products to run GUIs and they work like a champ.

    Mimo 7" USB touchscreen [] = $180

    Mimo 10" USB touchscreen [] = $260

    We use NT embedded but these also have OSX drivers, and if you want to use these with Unix you're not alone [].

  • Why not go to a FriendlyARM Mini2440? For about $150 you can pick it up from [] and you have a full fledged Linux board with plenty of i/o and touch screen...
    Happy hacking! Jasper
  • Ok, not too hard to find touch LCD panels online, but I wonder just what is the point of this device you are attempting to make?

    There are so many products in just about the size you are looking for I have to wonder why not either go with one of those products, either as the final device or a basis to create the device you want out of it?

    • Ok, not too hard to find touch LCD panels online, but I wonder just what is the point of this device you are attempting to make?

      I would imagine the point is the OP wants to build something him/herself.

      There are so many products in just about the size you are looking for I have to wonder why not either go with one of those products, either as the final device or a basis to create the device you want out of it?

      Well for one thing, building things has its own rewards. But also, a lot of times commerical products don't necessarily have the bells and whistles you want. The way I read the OP's post, he was already at the hobbiest electronics stage, and presumably wanted to advance beyond the simple blinky light stage. He/she wanted to know what was available in terms of displays.

      • by Jeng ( 926980 )

        He/she wanted to know what was available in terms of displays.

        It is easy enough to find general LCD touchscreens for hobbyists, that is just a google search away.

        To be able to recommend the best one for the purpose one must know the purpose.

        Once one knows the purpose you can either recommend them a specific part, or a complete device that could be cannibalized for not only the display, but many other internal parts that already work with the display.

        The more information given the better answer he'll get, and he didn't give enough information imo.

  • Might be worth looking into, bit pricey compared to Arduino though.

    But the starter kit comes with a mainboard and a 4" LCD touchscreen which is pretty decent for small projects. The hardware is largely made by GHI Electronics... []

    Not sure if this would be suitable or not...

  • Sparkfun (Score:5, Informative)

    by subreality ( 157447 ) on Thursday May 24, 2012 @03:44PM (#40102791)

    Sparkfun has lots of hobbyist-friendly parts, including LCDs: []

    The only thing they're missing from your requirements is an enclosure, but certainly you can hack something together.

  • I've been using Crystalfontz LCD displays in my projects for many years. []
  • by Anonymous Coward

  • If you do not mind making your own plastic case out of a project box, you can get a touch screen off of ebay. Check out ebay. [] (Or navigate to it through Business & Industrial >Electrical & Test Equipment >Electronic Components >Semiconductors & Actives >LCDs & Displays). You can find many 3.2" touch screens for $18 on ebay. I have even some sellers some that provided a link to demo to get the screen to work on some common MCUs. Many
    • We have been looking at one of the $16-$18 displays for a hobby project.

      Looks like a larger PIC would be able to drive it given enough I/O pins or some extra glue logic. The supplied interface needs a 16 bit parallel plus a 4w SPI for the touch sensor (plus a few control lines). A bit of a shame they did not bring out the mode control lines as the display controller appears to support a SPI interface directly.

      Also no built in ROM so you'll need some allocation for the character font you want to use.

  • Small LCDs in a variety of types and sizes with driver boards. []

  • HERE [].

    Lots of reasonably priced displays, some with touch and on-bard "intelligent" controllers.

  • get a arm system from minibox, 3.5 inch 400Mhz, 64 megs and plenty of serial ports to twiddle bits to an avr or whatever
  • OK, so maybe it won't fit your particular application, but I have in the past built my own multitouch table using an old LCD monitor, a couple of USB webcams, some clear acrylic, and a bit of hacker ingenuity.

    If you are tempted to go the DIY route, Community Core Vision [] a good place to start.

    Happeh hacking!
  • []

    Lots of different stuff you can do with it. Hope that helps.

  • You might check out what this guy has: [] Most (all?) of Ray's stuff is Parallax Propeller-based (~$8US 32bit 8-core MCU) He has 3.5", 4.3" and maybe other size panels and was at one time offering just the LCD's; ask him if he has any left if you want just them. There are already low-level drivers, and text/graphics primitives code ready to use with all his products, so you'd just be writing your application-specific code. Then this guy makes at least one acrylic enclosure made for R
  • Missing the point (Score:5, Informative)

    by michael_cain ( 66650 ) on Thursday May 24, 2012 @05:01PM (#40103825) Journal
    Clearly, I didn't make my point in the original post; my bad. The "pre-mounted in a plastic enclosure" is perhaps the most important feature. I know where to find naked displays; what I want to avoid is the homemade plastic box, with things cut/fastened ever so slightly off center, odd screws showing, etc. And while I appreciate the "just write an app" suggestions, in some cases the box will end up mounted on a wall, in at least one the controller will be driving relays to switch higher voltages, in another there will be some odd sensors, and so forth. Don't need processor boards, don't need an unmounted display. Need an LCD with touch panel mounted very neatly and solidly in a reasonable-looking box. Apologies for not being clearer.
    • by mvdw ( 613057 )
      Have you looked at Reach LCDs? Not sure if they are to your budget, but they have nicely housed touch-screen LCDs driven by an allegedly simple serial protocol. []
    • by src1138 ( 212903 )

      I would check out used/cheap PNDs. You get a minimal enclosure with enough room for a pcb and battery (you might even reuse the battery and maybe the charging circuit if possible). I bet you can find some older ones with 3-or-so inch resistive screens for under 40 bucks - probably 10 at a garage sale. As long as the enclosue, screen and battery are ok (you may not even want the battery) it should be a safe bet.

      Pawn shops (ahem) tend to have lots of these as well.

      Granted you are just hoping you can gracefu

    • by CityZen ( 464761 )

      Get a cheap Android tablet that has a USB host interface. Then attach all your relays and sensors via USB (or USB to serial, if need be).

    • Ask them to update your entry with your clarification, that way every one will know, this post could get obscured

    • Have you considered acrylic or Lucite? Possibly wood? Harbor Freight (US discount power tool chain) carries "good enough" routers for under $20, and a router + wood could make a very posh "luxury" facade for a touch screen... Polished screws with possibly non-standard heads in counter-sunk holes on the facade could be made to fit with the design aesthetic... you even see *fake* countersunk shiny screw heads on bezels of some devices, due to how it looks "high-end" in some contexts.

      So, RV or boat control p

    • Unfortunately the enclosure is hard. As hobbyists we have to frequently repurpose mass produced equipment. There are some things like circuit boards which can be made in small volumes economically, but displays and injection molded plastic enclosures have very high tooling costs, so you'd need to repurpose. In this case there's probably nothing premade that will meet your needs: small devices with touchscreens are almost universally designed to be hand-held, which means as small and light as possible. T

  • Depends on the project.
    I built a cheapy 4 line lcd/arduino interface for my custom security system for around 60 bucks. It was butt ugly because good cases are hard to find or expensive to custom build. My wife HATED it. So I found a cheapy android (1.5) ebook with wifi and rooted it for about $90 (could probably find it for 60 now) and wrote an android app. It looks WAY better than my butt ugly lcd and is also going to be an interface to my weather station (when I get around to finishing it) and a fe
  • You want a Chumby. Everything else lacks custom enclosures, or costs so much money you may as well buy a full PC.

  • by mcbridematt ( 544099 ) on Thursday May 24, 2012 @08:51PM (#40105443) Homepage Journal

    Search eBay - I bought a 3.2" LCD with touchscreen like this one [] (~$25) and I'm currently working on driving it with an ARM Cortex-M3 controller.

    The downside is that these ones are generally designed to interface with 8051 or 68000-type micros, hence they only expose the 16-bit parallel bus on the LCD controller. Not as optimal, but the displays are quite cheap.

  • There's no reason to put in yet another display and input device. Does your router need one? Just use the ones that you already have in abundance in your phones, tablets, and laptops. Make the protobox headless with networking, then get on with what you really want to play with, instead of yet another disposable MMI.
    • by sl3xd ( 111641 )

      Your argument is like saying somebody shouldn't cook, because there's an abundance of restaurants and prepackaged, prepared food.

      Some of us like designing hardware from components. We like designing circuits, laying out printed circuit boards (and fabricating them), component soldering - including things like toaster-oven reflow soldering. We like debugging wire protocols, using logic analyzers, and yes, programming microcontrollers.

      Being able to say "yes, I can design products that use a touch screen" can

  • Try looking at []

    They sell touchscreens around that size with a controller that you can either program using a C-like language, or send commands to from an AVR etc.

  • It's bigger than you wanted and not cheap but it does have an enclosure. It runs Linux. Boots really fast. Lots of I/O options. []

    You can also try Crystalfontz. They make lots of displays. Even OLEDs.

  • I have one from an old nokia cell phone 12 bit color, and you can get touch screens. Try [] they will have what you need.
  • there have been a number of apps which turn a PalmOs handheld into a usb-attached LCD display; Palms with mono and colour displays are cheap on ebay.

Always leave room to add an explanation if it doesn't work out.