Touchscreen and Propeller?

SuperCricket

I'm wondering if anyone has got a touchscreen working instead of a regular mouse. I've got a virtual keypad in the vga object and want to use a touchscreen to get the user input. seems like the ones at work are all USB inputs to the computer with software in windows xp for them. not sure if it will interface with the Prop without special drivers. any ideas?

Mike Green

You can't really use a USB touchscreen with a Propeller. The existing mouse routines are for PS/2 mice. There have been some people experimenting with USB drivers for the Propeller, but they're large and complex and, so far, not suitable for general use, certainly not by people who have only limited experience in debugging or modifying complex I/O drivers.

You might have an easier time using a USB host like the Vinculum chip that's part of Parallax's USB Memory Stick Datalogger and several versions sold by FTDI as well. This has the capability of talking to USB HID devices like a touchscreen or mouse, but you'll have to do your own programming.

Post Edited (Mike Green) : 6/1/2008 12:37:26 AM GMT

StefanL38

Hello Supercricket,

welcome to the forum ! On my earlier job it was vice versa. All the touchscreens had a serial RS232-Interface.
But these monitors were all of a high-professional quality for industrial use (prices of 1200 up to 2000 dollars).

Did you ever made a productsearch on the internet for touchscreens with serial interfaces ?

best regards

Stefan

Tubular

Hi SC, are you looking for a complete unit with display/touch sensor/connectors, or rolling your own?

If rolling your own, what size? What kind of budget? I have some Gunze modules which put out RS232 in simple ascii x,y positions. I normally use these with 15" touch glass but believe they would work with other sizes just fine. However you would have to level shift back from the RS232 to suit the prop.

Mike Huselton

See this for an idea of rs232 add-on touch panel costs:
http://store.earthlcd.com/LCD-Products/Add-On-Touch-Screen-Kits

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JMH

Rayman

Look here:

http://forums.parallax.com/showthread.php?p=713258

for how I used the 5-wire touchscreens from Digikey with a regular monitor to make a touchscreen that works with the PS/2 port of the proto board...

SuperCricket

Hey Rayman seriously thanks for the help with that. I'll pick up the right sized touch screen and the controller board and post my results back in here. I'll hit you up if I come across any snags. Glad these message boards are here for all the Propellerheads.

Mike Huselton

Far out, Rayman!. I can think of uses for this technique, and the cost is quite reasonable.
Thanks for the tip...

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JMH

Ken Peterson

I wrote a touch screen controller for the Prop that drives a 4-wire touch screen directly (no serial or USB controller). I didn't post it on the OBEX because I haven't had the time to polish it up nice. If you are interested, send me a private message and I can get you a copy of what I have to get you started.

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jazzed

Ken do you have an idea of what the schematic and components would be on the inputs? I've considered doing a driver like this myself, but haven't had much time. Can you PM me your details? TIA

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Agent420

I haven't done a touchscreen project yet, but it's my understanding that most of these use resistive layers that you simply measure with an adc of some type.· It's more programming logic (like dealing with a joystick) than hardware.

But take a peek at either MikroElectronica (or their US retailer Circuit Ed)... they have inexpensive·touch screen material, interface boards and complete assemblies.

http://www.mikroe.com/pdf/touch_screen_specification.pdf

http://www.circuit-ed.com/LCD-and-Adapters-C8.aspx

edit -

Guess you're looking for something larger, but I still think that most of these are going to be 4 wire resistive, in which case you can probably tear it open and go right to the touch material with an adc·if need be.· Just think of the plastic layers as two potentiometers...


Post Edited (Agent420) : 6/2/2008 3:46:09 PM GMT

Rayman

SuperCricket said...
...·I'll pick up the right sized touch screen and the controller board and post my results back in here. I'll hit you up if I come across any snags. ...

The most difficult part is getting the touchscreen installed inside the monitor.· The main difficulty is keeping the bezel from pushing onto the sensitive part of the screen.·· We wound up gluing plastic spacers around the edge of the touchscreen to keep a gap there...· Also took cutters to the bezel to remove the inner edge that wants to push down on the screen...

Ken Peterson

@jazzed:

Here's·the latest version of my driver.· Should be pretty straight-forward to use.· Let me know if you have any questions.



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Rayman

Just FYI: The 4-wire and 5-wire screens are very different... Something like Ken's object would work for a 5-wire screen, but only one ADC is needed (on one wire). And, you need to tri-state output the right voltages on the other 4 wires...

Ken Peterson

Also, you can reduce the number of Prop pins needed if you use external complimentary MOS drivers. Theoretically, for a 5-wire panel: 2 pins for ADC and one to switch between driving X and Y.

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jazzed

Your work looks good Ken. Thanks for sharing. Considering the number of pins required and the tiny number I have left, using an RS232 interface would likely be best for my application (dang it). ... unless I bite the bullet and use Prop as my multi-i/o peripheral device.

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rjo_

4D Systems http://www.4dsystems.com.au/products.php
has a serial touch screen on the way ... http://www.4dsystems.com.au/prod.php?id=23

Tubular

rjo_ 4D have actually released the Active OLED touch equivalent in 2.4" and 2.83". Gorgeous displays if the size and budget allow.

http://www.dontronics-shop.com/micro-oled.html

rjo_

OOPS...