Light-pens... The principle behid this device is perfectly understandable and simple (ingenious even).

Picture on regular monitors (Cathode Ray Tube monitors (CRT)) is formed in series of horizontal lines that stream over and over again many times in a second across the whole front surface of the screen. Light-pen is a pointing device that senses the light from the ray forming those lines on a monitor; it senses light ray at a certan time since the ray started its path, and acording to that time it calculates and determines where you placed the pen on screen at that point in time - that information is sent back to computer and it places the cursor at that coordinate.


I can't seem to find much information about light-pens on web, which means that it isn't used very much. WHY?

Is it too inacurate? (theory is one, practise is something else - maybe that mechaism has flaws)

If not - then I can't understand it (can't imagine some other reason not to put it in the widest use (...except legal ones...)) - because light pens are the most natural way to point on screen (especially if you have a hole in a desk and you place your monitor in it, so you draw on it like on a paper).

Why isn't it used!?!

Can someone explain this phenomenon?

(maybe someone had an opportunty to use it - share your expirience - is light-pen worth it if you plan to use it to draw stuff (light-pen mind you, not touch-screen with a pen))

13 Years
Discussion Span
Last Post by asrekdal

The Wiki on this subject sheds some light on why the light pen is remembered in the same era as the original Star Wars episodes and Easy Bake Ovens.

Yes, infact that was the only place I've found some answers on what I asked here afterwards... (that "arm-tireing" problem can be solved by the above mentioned hole-in-the-desk routine, but I'm not sure about the problems with connections to the system)

I've found some places on net where they offer light-pens for PC's (e.g. http://www.cw2.co.uk/index.html). I guess manufacturers won't tell if there are some flaws.

I wanted to know about some expiriences straight from some PC light-pen users (what they say about it - HOW PRECISE IS IT? Is it worth buying?).


I have a couple of those sitting in a closet somewhere...

They were not very accurate for drawing but they would probably work ok for clicking buttons inside a program.

Unless you have a special need to not use a mouse there is not reason to use one.


My experience with light pens is very limited, but if I were to chose between being able to move a pointer across two screens with a flick of the wrist or having to move my entire arm while supporting the weight of it with my shoulder, I'd chose the flick of the wrist.

The evolution the light pen is a digital tablet. Digital tablets, combine the tactile sensation of light pens with the ease of use of a mouse.


OK - digital tablet - it's easier to find it and buy it anyway, but I need it to draw stuff - with digital tablet you draw on one place, and result comes out on the other place (monitor) - which is similar to the mouse - so we didn't go that much far away from where we started, did we(?)...

...I saw on the Net (actualy I first heard about it from some salesman) about those touchscreen add-ons (transparent layer fixed on the front of the screen of a monitor) - check this out: http://www.magictouch.com/addon.html

Has anyone had an expirince with one of these things? How precise are they? Are there some possible problems with it?


Don't sell digital tablets short. Check out the Cintiq 21UX. A little pricey (okay... very pricey), but exteme accuracy and ease of use.

I thought your reason for starting this topic was to find out information about light pens, not to find a solution that you could use. What exactly is it that you want to do, and what is the ideal solution in your opinion (ignoring whether or not the solution exists)?


Don't sell digital tablets short. Check out the Cintiq 21UX. A little pricey (okay... very pricey), but exteme accuracy and ease of use.

I thought your reason for starting this topic was to find out information about light pens, not to find a solution that you could use. What exactly is it that you want to do, and what is the ideal solution in your opinion (ignoring whether or not the solution exists)?

(Thanks for the link.)

Cintiq 21UX. Well... yes, it's very pricey (3000$)! First time I heard for WACOM firm was two days ago in some computer shop when I was looking for some solution on this issue of mine - I didn't even know the price ratios so I coudn't compare - complete lack of perspective for these things (they too were saying that WACOM's products are top class in this domain (they showed me some WACOM tablet (costing 85$ or so - I don't remember...))).

About your question:
Rule: The more comparable to drawing on paper, the more ideal is the device for drawing using computer... (logical...) ...and of course - price...

That's why I stick to the Light-pen - I mean: (to answer your question) if it works correctly (if it's precise) - it's the best thing there can be(!) - IDEAL SOLUTION (to use your term): just a pen (and you use your monitor) - no aditional robust devices equals less money to pay.
IT IS the reason for starting this topic (information about light-pens themselves). That's the main talk. That's the point.

For example: maybe light-pen gets a wrong input if you change it's angle (picks up a wrong line) - I don't know, maybe someone else does?

It's all so fishy...


(Just by-the way: CONCEPTUALY second best solution (I think) is that touch-screen add-on (a transparent layer for monitor and a pen - it can't be that pricey); but also don't know how good it is.)

Light-pens - definitely... it's the ideal solution (that's the best concept - no matter what (but does it really work - that's the only question I ask here)); and I started this topic because I was suspicious about it's quality because there's not much evidence of lightpen for PC usage on the Internet, not to mention that I can't find them in the computer shops here (not a single model!). (I have some cheap plastic can-see-LED-on-tip lowsy light-pen for Commodore 64 for a long time now, though... never worked...).
The best thing for me would be if someone would come and say - "I use light-pen, it is very precise, fast and reliable - check this one!", beacuse I prefere that solution - that's the first one on my priority list anyway (I insist on it - that IS the whole point of this topic...).

On the other hand that 'Cintiq 21UX' concept sounds like the best possible in professional terms (ultimate) solution for drawing - ideal (the price part on the other hand doesn't seem like it)...

(actually - it's an LCD portable touchscreen monitor! isn't it? They just call it a "tablet", but let's stop kidding, it's more than a tablet (much more...)).

Anyway... That day (two days ago) I bought a ' Genius WizardPen 5"x4" ' (http://www.geniusnet.com.tw/product/product-1.asp?pdtno=70 ) tablet (a simple thingy really - flat board with USB cable, pen with AAA battery) for about 38$ to try it out - anyhow it's cheap - so I thought "I might give it a go." - doesn't matter, and it's nice - consider it a review (but not perfect, not a professional solution anyway (you draw on one place and the result comes on the other (monitor) - that's unnatural (just like a mouse)...) - but, that's a tablet), it gives some good results, it's prety much precise - no worries about that whatsoever (also is pressure sensitive (1024 levels of pressure - the utility program says)) - you must start from somewhere and this (a tablet) is a good way to do so - definitely; you just need to allow some time to adapt to the technique - to get use to it (I even tried to put a piece of paper on a tablet's surface (because the surface itself is slipery), and achieved better results when drawing (more control over pen (and because paper is a little bit elevated from the tablet's surface you can feel when it's about to touch the surface (which means: less probability to incidently touch it, which is equal to the left mouse button action))), but I would't recomend paper, because (I don't know) it may damage the pen tip (there's more friction with a paper)).

(It's strange at the begining: few times I automaticaly tried that mouse movement routine ("lift-moveback-rollagain" routine you do so you don't "drive" mouse across the surface and have to lift your wrist of the surface), forgetting that tablet doesn't work that way, and also at the begining it requires some attention to actually click the button on the pen (separate keys on tablet or keyboard suppement keys would be a nice option...))


But, let's talk light-pen.

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