How to fit a square momentary switch in a round pen body

[Pengwuino]

Yes, the subject sounds stupid but the question is even stupider!

ever since I was a kid I've liked building things, especially with electronics but I've never had any real education towards it etc etc no skills blah blah. Right now I want to build an IR pen for a project that was posted a while ago on the forum. The idea is to make a pen like:

http://johnnylee.net/projects/wii/pen.jpg

The problem is every momentary switch I see online, like http://www.sparkfun.com/commerce/product_info.php?products_id=8720" that is actually low-profile enough is build like a square, for lack of better terminology. The button is suppose to be in the pen so that you can press the button easily as if you were going to write with the pen. The button is square, the pen is hollow and round. How do you put this together? Also, the LED is smaller then the open end of the pen casing so I need to figure out how to make it fit more snug...

Where do I learn to make crazy cool gadgets!? I need some sort of ... metal... that's like playdough but its metal!

 

[Proton Soup]

a switch like that is just two pieces of metal and a spring. the spring could actually be one of the strips of metal. you just need materials with the right shape and characteristics. springy. corrosion-resistant. conductive. something like beryllium copper might be ideal, but brass maybe, or steel. just whatever you can salvage out of the broken electronics bin and can bend/cut/file/solder in place. mostly you just need imagination, tho.

 

[Danger]

You could try scavenging a switch from some pre-existing product. I do that all the time. Or, you could simply build one. The easiest way would be to get a regular square housing microswitch that's smaller than the pen barrel and pad it to fit.
As for the material you want, I recommend JB Weld. It's a binary epoxy that you stir together and it becomes a semi-thick paste. When it hardens, it's as strong as steel. You can mend trailer hitches with it.

 

[Pengwuino]

I was thinking of some sort of non-conductive block of material that i could etch some paths for the current and glue that into the pen casing I have. Too bad I don't know how to etch... Then I could just cut away at the material so it fits into the pen haha

 

[Proton Soup]

i've actually got a cheap mechanical pencil here that has a button built into the side. the spring is in the tip where the LED would be located. you'd have to build a new spring under the button after removing the force-transfering mechanism and still leave room for the return wire to pass. but the battery would have to be smaller than even a AAA to fit in the eraser/lead cavity, even with the eraser holder stripped out. maybe look for something similar to alter, like... a penlight? ;)

https://www.pentelstore.com/index.php?grp=759

 

[n!kofeyn]

Your question "How do you build stuff?" reminded me of MIT's class, How to Make (Almost) Anything. I first came across this class when someone linked to this guy's http://fab.media.mit.edu/classes/MIT/863.08/people/ryan/week13.html" site and scroll down to their classes (the guy I linked to was in the '08 class). I thought you might be interested in it. I wish I could've taken part in a class like this. Super cool it is.

 

[Kenneth Mann]

I'm not sure of what you want, but there is an illuminated ball point on the market somewhere (I have one, which I got from a neighbor). It has a button at the end which turns on and off a light in the barrel (possibly a LED). The writing point is extended and retracted by twisting the barrel. The light is in the upper part and projects down through the barrel which is transparent. This could probably be replaced with an opaque barrel which has an opening in the end. I don't know how to get one though.

KM

 

[physics girl phd]

Just use lots of glue... For electronics, that conductive epoxy! (just kidding)