OT: Control display of a portable LCD screen

mdog has asked for the wisdom of the Perl Monks concerning the following question:

Brethern --

I know that this an extremly crazy question but does anyone know of a way to control the text that appears on a portable LCD screen? This is hypothetical but I'd be willing to buy whatever LCD device that could take updates when not attached to a computer.

Any monks know of a way to update an LCD display with no wires from 10 feet away to 30 miles? I imagine there would need to be a service that would allow you to send RF signals (and there can't be any service like that) or the device could be like a pager with wireless service and could parse an email and just display the text of the email on screen. Ideally, the screen wouldn't be any bigger than 6 x 3 inches (or something in that size range).

Just something to mull over...I'd appreciate any ideas folk have to offer.

Many thank,
mdog

PS Of course, I plan on communicating with said device with perl!

Comment on OT: Control display of a portable LCD screen

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Re: Slightly OT: Control display of a portable LCD screen by InfiniteSilence (Curate) on Oct 31, 2005 at 19:47 UTC
Actually, this type of stuff has already been done in the Amateur Radio community. There is even an example of some perl code that uses Win32::SerialPort to communicate with a pager. Of couse, this is an amateur set up and you will need a license to do this in the amateur bands (as stated on the page). Not sure if you are doing this for fun or as a proof-of-concept for something professional. In the latter case, licensing is going to cost you some $$$. If you want to experiment though, and you don't have a license, locate your local Amateur Radio club (there is always one nearby) and get a licensed operator to work with you. That will make it legal. Celebrate Intellectual Diversity	[reply]
Re: Slightly OT: Control display of a portable LCD screen by gri6507 (Deacon) on Oct 31, 2005 at 19:35 UTC
This truly is off-topic, but in the spirit of the question ... If you are trying to control a 7-segment type LCD screen with say two lines of ten 7-segment characters each, then you would first need a hardware driver for the LCD and then some way to talk to the driver. Usually, those drivers can be talked to through serial-type communication, where bits are shifted in with an external clock. Since your computer only knows about RS-232 serial ports, you'd have to rig up your hardware with some kind of a processor (like the PIC uC from Microchip) and then have this processor generate the clock and shift out the bits. On the other hand, if you are talking about a larger dot matrix type LCD screen, then the drivers become much more complicated to control (I personally have never dealt with those). Likewise, if you are interested in driving a color LCD (like a 3"x5"), then the control is even more cumbersome, however, even that can be done with PICs (two actually because the horsepower of one is not enough for both Vsynch and HSynch). As for remote control, well, you are off into another realm of problems. Digikey sells some RF transmitters/receivers that are fairly easy (relatively speaking) to implement with a PIC, but I'm not sure if those will be able to work over 30m. Hope this helps.	[reply]