Author Topic: Pressure sensative "real" IR pen  (Read 7798 times)

Offline silkcom

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on: February 27, 2008, 02:58:48 PM
Ok, this is an idea that i've been thinking about lately, and finally came up with a cheap and easy solution.  The result is an IR pen that is on while you're writing and off while you're not.  It uses the spring inside a pen to push the connections apart, and pressure on the whiteboard to push them together, so the IR is on when the connections are together and you are writing, and off when they are apart (it's sitting on the couch).

I've created an extremely crude drawing of it.

Here's what you need:
A plastic pen (with a plastic tip that screws off)
An IR LED
Small wire you can find
Glue of some form (super glue would probably work, though this is still just a theory)
Dead (or not) Whiteboard marker

and tools to do the idea.

So far this is an idea, I just fit it together and haven't created the pen yet.  If you have any ideas to improve this let me know.

I've put most of the instructions on the drawing. 

Note that when the Pen Tip, and the "Something Metal" touch the battery should then flow through the IR LED, so setup the wiring accordingly.  Also the back of the pen is attached to the IR LED so that it won't move, use whatever u want to make this happen, probably super glue again.

File down the tip of the plastic pen top to make this thing a little more sensitive if you want too (this brings the 2 metal pieces closer together, and requires the spring to move a smaller amount).


Here's what it's missing:

You need something on the IR to keep it from falling out of the hole could be anything smaller than the lip of the LED, I'll give pics of the real thing once I find a suitable solution to this.  Other than that it's just hooking the metal on the IR to the correct stuff and including a battery, this is easy enough so I didn't go into it.



Offline Beachbum

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Reply #1 on: March 21, 2008, 11:16:08 AM
i've been thinking about doing something very similar. my idea however involves using the mechanism already contained within a "click" pen. the pen would essentially be held backwards with the led mounted in or on the clicker part. one benefit, if it can be seen as one, would be the possibly of having a light that could stay one if so desired (by clicking the pen) or only on when pressure is applied. i'm not very good electronically, so i haven't figured out an exact design, but it shouldn't be too difficult. i have screwed around while holding a pen backwards and the usually pressure applied when writing is sufficient to depress the clicker, but not enough to fully click the pen. if you have any ideas, please let me know. also, if you can think of or notice a pen big enough to hold at least 1AAA battery, let me know. thanks



Offline Kamitsuna

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Reply #2 on: April 10, 2008, 02:23:57 PM
why not have the LED just press down on a momentary switch?
Seems pretty reasonable to me. Or if you have to, super glue a toothpick to the bottom of the LED between the contacts and have the toothpick press down on the momentary switch.



Offline UndCon

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Reply #3 on: April 10, 2008, 05:49:53 PM
Yes it sounds easier to glue the IRled to the top-cap of a switch and place them inline inside the pen

My son had a ballpoint pen that lit up with a red LED when it was used - a similar setup but this was even simpler - a spring made the reservoar move freely for a few mm and when it was compressed it made a shortcut in the LEDcircuit - really simple...



Offline Flub

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Reply #4 on: April 18, 2008, 12:05:27 PM
I just tried the idea of glue it onto the cap, but its not very stable... But Ill keep it on and Ill try to make a very good pen with which its nice to draw and realistic in pressure

wouldnt it be nice if there is a dimmer in the pen that allows you to make weak and strong lines in photshop^^?



Offline UndCon

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Reply #5 on: April 18, 2008, 12:39:32 PM
I also secured the LED with some glue...

The LEd is press-fitted to place but it's very easy to move the LED out of place when removing pen-cap...

I put the LED back in place (no tools) and applied a ring of superglue around it - now its permanent :)



Offline atomriot

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Reply #6 on: April 19, 2008, 12:25:40 AM
some super glue (future glue in my case) is conductive. i learned that the hard way. heh. i only use hot glue now.

Details, details. Things to do. Things to get done. Don't bother me with details, just tell me when they're done.
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James Lionel Price



Offline JDuzio

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Reply #7 on: May 03, 2008, 08:40:11 PM