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Ask Slashdot: Hobbyist-Ready LCD Touch Panel For Embedded Projects?
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?"
http://www.adafruit.com/products/376
2.8", touch screen, colour. /shrugs/
says it all
Sounds like the kind of thing that people who build in-car systems would know about.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
http://arduino.cc/playground/SmartGPU/SmartGPU
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. http://www.sparkfun.com/categories/147
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
Evil is as eval("does");
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.
www.amulettechnologies.com
http://www.logicsupply.com/categories/touchscreen_displays
They might be more expensive than you're looking for, but they have a nice selection.
Learning HOW to think is more important than learning WHAT to think.
http://www.adafruit.com/category/63 http://www.sparkfun.com/categories/76
It all starts at 0
Dunno, without knowing exactly what his planned use is, odds are a COTS solution is something to consider. A cheap tablet or phone that can be hacked to get a bit of I/O or that has USB host mode support just might be the fastest and cheapest way to solve the problem. After all he wants a bitmapped touchscreen and driving that is outside what I'd want to be doing on most AVRs, especially ones available in DIP packages.
Democrat delenda est
What the fuck is it with people suggesting "get a Tablet" to almost every single question that comes up these days?
"My car has trouble starting in the mornings..."
"Get a tablet!"
"My pool filter seems not to be doing it's job very well lately..."
"Dude, tablet!!"
"What's the best product to get stains out of concrete?"
"TABLET!!!!!!!!!!!"
Tablets are great for some applications, but not every application that involves tech in any way, shape, or form.
Sparkfun has lots of hobbyist-friendly parts, including LCDs: http://www.sparkfun.com/categories/76?sort_by=price_desc
The only thing they're missing from your requirements is an enclosure, but certainly you can hack something together.
I feel like perhaps you would be a less angry person if you had an iPad. Have you considered getting an iPad? Also, decaf. Decaf is good.
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.
he gives them to me for almost everything I've got.
if this is supposed to be a new economy, how come they still want my old fashioned money?
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.
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.