feasibility study of touchscreen controller - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: July 10, 2014, 06:40:52 am
content: After yet another delayed delivery of our off the shelf air conditioning controllers a bit of banter started in the office that I should just design our own one, of course the guy in the office that understands the least about electronics wants the moon possibly.So while this won't happen soon and i may not even have the skills yet to accomplish it I don't even know where to start.What we would be looking to achieve is a touchscreen panel as a finished item with a surround that can be fitted into a dashboard. Now i can easily write C programming to control the actual air con system it's the touchscreen interface and graphical side of it that I'm clueless on. My colleague seems to think that we can buy something customizable off the shelf. So what are out options.I need to read sensors and control actuators and I can do all of that, how do i add the touchscreen interface to it and what is there available of semibuilt and customizable that don't break the bank?

author: pickle9000
author_rank: Super Contributor
timestamp: July 10, 2014, 07:01:35 am
content: Can I ask how rough the operators are?Are you looking for colour?How big?I don't think a display of this type is beyond you. Graphical displays are nice because once you have a basic setup they are easy to use in the next application.

author: Simon
author_rank: Unknown
timestamp: July 10, 2014, 07:08:00 am
content: 1) I don't know, we would be looking at farm machinery initially2) Preferably3) No idea 3 inches is a good start

author: Legit-Design
author_rank: Frequent Contributor
timestamp: July 10, 2014, 07:35:44 am
content: http://www.eurek.it/i-prodotti/piccolo-touchSomething like this? cortex M3, display, touchscreen.Or you could go to the moon and get android HMI devices with all kinds of certifications and just slap android app in there? As far as I know there are not much options for fully customizable GUI on budget. Probably cortex M3 type processor and using premade libraries for NXP LPC or ST STM32. SWIM or emWinhttp://www.teamfdi.com/development-tools-kits/products/6/uEZGUI-1788-43WQSQuoteThe more DIY and non production ready it is, the cheaper it will be.I recently watched this and found it to be both entertaining and not a total waste of time. Manually doing the graphical stuff without library and tools to do the very basic things doesn't sound like fun thing at all. For example he talks about spending entire days to get a button correct in code because it's few pixels off. And with library can just drag and drop everything in place and call it a day.Claimedproduction readyhttp://www.teamfdi.com/development-tools-kits/products/1/uEZGUI-1788-43WQR-BAQuotehttp://fi.mouser.com/ProductDetail/FDI/UEZGUI-1788-43WQR-BA/?qs=sGAEpiMZZMvo7MPqW45u%252bIOmmAxgs2oMIs ~150€/unit too much?

author: FreddyVictor
author_rank: Regular Contributor
timestamp: July 10, 2014, 07:39:27 am
content: nice LCD touchscreens from4D Systemshas design software for the GUI, whether this is beyond your capability ......UK distributorsee u-tube for example applications

author: pickle9000
author_rank: Super Contributor
timestamp: July 10, 2014, 08:08:17 am
content: It doesn't sound like you are doing anything more than a basic control display. You may have or use colour but it will be used for notification purposes. No real need to draw a bird mountain scene or have extensive menus.- Do the old way fast and simple, get a display you can live with and that is part of a family (popular and long production time).- Do bitmaps (images) for basic modes and use blank space to keep it tidy.- If there are routines provided by anyone (assuming it's legal) and it makes your life easier use them.Just read the code, it should become clear what's going on. Even if you decided to go with a more complex setup you still need to get the stuff on the screen and that if what I'd like you to look at. It's not severely complicated.I hate to point you at this but look at the bottom of the page for the code sample. I assume you can read some c. (I hope)http://forum.arduino.cc/index.php?topic=175751.0

author: G7PSK
author_rank: Super Contributor
timestamp: July 10, 2014, 12:42:19 pm
content: Quote from: Simon on July 10, 2014, 07:08:00 amMy experience with farmers is if it can be broken it will be and if you think it cant be broken they will have a good try and in most circumstances succeed.

author: Simon
author_rank: Unknown
timestamp: July 10, 2014, 12:55:47 pm
content: Oh these are high tech farmersapparently the new vehicles have complete dash board and controls done with them on a 15" screen

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 10, 2014, 03:30:12 pm
content: it can be done with avr chip...the problem is only conencting those "synapses"... google is your friendhttps://www.google.com.my/search?q=gui+for+microcontroller&rls=com.microsoft:en-us&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1&gws_rd=cr,ssl&ei=H7C-U-7kKo_JuAS2qoCgBweg...http://www.easygui.com/main.asp?sc=9&me=13&sub=27

author: pickle9000
author_rank: Super Contributor
timestamp: July 10, 2014, 05:44:23 pm
content: Have a look at this. It's an Arduino graphics library manual.

author: SirNick
author_rank: Frequent Contributor
timestamp: July 10, 2014, 07:02:11 pm
content: At the low end, just about anything graphical you can buy from Adafruit is supported by their in-house graphics library and display-specific drivers. They tend to be Arduino-centric, but if you know C++, you can strip it all down to the basics and port to any platform you want. At this point, you have graphics primitives (lines, boxes, ellipseses, etc.), as well as support for images, so design your GUI, code your event handler, and away you go.A slightly more expensive option is the line of displays with built-in graphics controller from 4D.If you want something more GUI-centric, you're probably better off stepping up to emwin or the like, on a Cortex M. Get a demo board with LCD and play with the examples. If that combo suits you, just look for a panel with an interface compatible with the micro (which will be readily available).

author: Dongulus
author_rank: Regular Contributor
timestamp: July 10, 2014, 08:15:46 pm
content: I don't know about any pre-built solutions.However, I do recall that STMicroelectronics has tools available for GUI development. The STM32 line can drive LCDs and ST offers free libraries and tools. Here's some anapp noteabout their libraries. Might be worth looking into if you eventually decide to go for a board design. In fact, you could just copy what they have from STM32F429 development board because they offer a schematic on their website .

author: MacAttak
author_rank: Unknown
timestamp: July 11, 2014, 03:11:15 am
content: What's wrong with using a tablet with bluetooth capability and a paired microcontroller board that you build? The microcontroller can do all of the system controls, and can be installed into a sturdy enclosure and hidden away. Tablets are commodity devices now, and easily replaced if it breaks. This also gives you a huge benefit of having access to a very mature and powerful UI stack courtesy of the tablet's software platform. And if you don't feel up to the UI design/code challenges then you can easily find contractors who specialize in mobile application development to do that part for you.Side bonus: the driver can turn on autopilot mode (those big tractors can usually drive themselves) and play Solitaire on the tablet. Everybody wins!

author: Legit-Design
author_rank: Frequent Contributor
timestamp: July 11, 2014, 03:27:47 am
content: Put SOAP router in it! As a bonus you gain some internets! All this new wireless display technology is so weird and wonderful. Plus they made it easy to use for stupid people. Since it uses smart routing technology it can find routes in the fields like no other.https://www.indiegogo.com/projects/soap-the-intelligent-touchscreen-quad-band-router-smart-automation-centerWith soap router you can control it from anywhere in the world? Just go to caribbean islands and lay on the beach and have your harvesters do the work for you.

author: miguelvp
author_rank: Super Contributor
timestamp: July 11, 2014, 03:33:00 am
content: Just don't forget to charge your device with internetshttps://www.indiegogo.com/projects/wifiexhmm, I guess indiegogo pull the plug on the rechargeable internet device covering the whole planet with satellites for just $400,000kidding aside, I think MacAttak has the right idea.

author: pickle9000
author_rank: Super Contributor
timestamp: July 11, 2014, 04:02:52 am
content: Quote from: MacAttak on July 11, 2014, 03:11:15 amThe simple answer is price. Many heavy equipment manufacturers (similar class) cringe at putting flashy stuff in. This application could be served by a numerical display to show temp, a couple of mode leds and an encoder knob to set the temp. Simple and robust. A touch screen need only emulate that level of interface. Show temp, setpoint, and whatever else the AC needs, perhaps diagnostics.Done well the box could be repurposed for other simple tasks, raising and lowering and accessory, could even have the name and an image of the item, even a locked in position indicator. Yes you would need a couple driver/input boards but they contain parts subject to failure so best to give them on their own pcb anyway. Why go for a system like this simple, the hardware part can stay as is for many years.

author: SirNick
author_rank: Frequent Contributor
timestamp: July 11, 2014, 07:11:06 pm
content: Bluetooth and WiFi are great and all, but really... KISS. A micro, LCD, and a few GPIO ports are pretty cheap and easy to assemble. Any time I see a tablet doing a microcontroller's job, I can't help but think "hack job". It's gross overkill that's more likely to break than something that is built to purpose.On the flip side of that, I agree having options for expansion is a good idea. Maybe the controller can use i2c or CANbus, and your GPIO can be external. A simple firmware upgrade and another device board on the bus, and you can add control for whatever today's emerging tractor accessories market throws at you.

author: pickle9000
author_rank: Super Contributor
timestamp: July 11, 2014, 07:16:08 pm
content: Quote from: SirNick on July 11, 2014, 07:11:06 pmI totally agree.

author: Rufus
author_rank: Super Contributor
timestamp: July 11, 2014, 08:15:28 pm
content: The trouble with any cheap LCD display is they are produced on the back of millions of sales of products with 1-2 years lifetime. Finding an LCD display you know you will still be able to buy in 5 years time is challenging.A common industrial strength solution for low volumes would be HMIs like herehttp://shop.maple-systems.com/merchant.mvc?Screen=CTGY&Store_Code=MS&Category_Code=GraphicHMIComprehensive software for designing the UI and fairly simple PLC type protocols for talking to the 'machine'.

author: SirNick
author_rank: Frequent Contributor
timestamp: July 11, 2014, 08:53:00 pm
content: That's a fair point, however... it needn't be the exact same LCD. If you buy a micro with a built-in LCD controller, it will speak some fairly common protocol, and any compatible panel will do just fine. Likewise, if you spec an LCD that uses a simple parallel or SPI interface, then any subsequent panel is trivial to adapt even if you decide to change micros.No one wants to reinvent the wheel, but if the interface can be made modular, then you tweak a config file, maybe spin a new bezel, and you're back in production. At most, you're forced to write (or find) a new driver library. That's not nothing, but it's not bad in the scheme of things.For that matter, will you still be able to acquire the same tablet in 5 years? Will it be able to run the same mobile app w/o changes? Nothing is certain.

author: free_electron
author_rank: Super Contributor
timestamp: July 11, 2014, 08:56:28 pm
content: get the tft toolkit from mikroesimply draw your screens like in visual studio. buttons, sliders , textboxes whatever.then attach your code.done. supports all common tft displays with embedded controllers and touchscreens.

author: Legit-Design
author_rank: Frequent Contributor
timestamp: July 13, 2014, 06:43:22 am
content: Quote from: Simon on July 10, 2014, 07:08:00 amWhat about screen update speed? People are used to "60fps awesome graphics" with their smartphones and computers. What if the user interface is awfully laggy and slow with some bottom of the range microcontroller? First thing when they see something working slower than usual is to ask if they have received faulty displays...

author: pickle9000
author_rank: Super Contributor
timestamp: July 13, 2014, 07:29:23 am
content: Quote from: Legit-Design on July 13, 2014, 06:43:22 amA control system update speeds of less than 10 frames per second (usually much less) are all that's needed. An lcd on a good multimeter will update 4 times per second. The layout or the graphics are whats critical. Keeping most of the display static helps the illusion and gives the display a look that can be carried through the design.The most critical update rates would only be needed during actual temp adjustment and even then it need not be high. A couple up down arrows that change a two digit number (the rest of the screen remains the same). There is a reason you often see 4 updates per second in multimeters and 2 is not uncommon in a cheap one.Again just my opinion for this particular application, the control of an air conditioner.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 13, 2014, 11:11:49 am
content: Quote from: Legit-Design on July 13, 2014, 06:43:22 amits a marketing hype in darwinian era, 25-30fps is the threshold down to 15fps still acceptable.

author: SirNick
author_rank: Frequent Contributor
timestamp: July 13, 2014, 11:38:29 pm
content: I have an Arduino (ATmega328P @ 16MHz) reading a MSGEQ7 IC (analog audio to 7-band spectrum analyzer) via ADC, and updating a 32x16 RGB LED matrix with soft PWM for color mixing. It can run fast enough to look completely fluid.You should be able to drive a moderate-resolution LCD with a reasonable control interface (one that doesn't require PWM for color) on a Cortex M with absolutely no concern over perceived frame rate.