Author Topic: Homemade telescopic IR wand  (Read 7973 times)

Offline Fastolfe

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on: March 08, 2009, 12:48:05 PM
Hello everybody,

I am to do a presentation next wednesday on a very large display, so using a pen wasn't exactly an option, as I couldn't reach the top of the display. So I needed a wand, but since I carry all my presentation gear (wiimotes, pens, batteries...) in a small case, I didn't want to have to carry a great big stick separately. So instead I bought a car cell phone charger with a retractable cord at the flee market, and hacked it to convert my old telescopic pointer pen into a telescopic IR wand.

The charger thing had a thin cord that you could pull out, and a button to release the ratcheting mechanism inside and store the cord back inside on a spring-loaded spool. There are two contacts on the spool and two tracks on a PCB to carry the electrical signal to the wire. Essentially just the same mechanism as on any vaccuum cleaner.

So I opened it up, removed the ratchet button, de-soldered all the components, soldered a battery connector near the cigarette lighter plug end, removed the fuse and cigarette lighter contacts to accomodate a short LR1 battery (and reused the spring as + contact), then threaded the wire into the telescopic pen, soldered one of our beloved Vishay TSAL6400 LEDs to the wire, glued the LED to the pen's removable tip, screws the tip back on, and locked the entire telescopic pen / charger assembly into place with Polymorph plastic.

The result is a bit ugly but it's very functional, and there are no wires hanging on the outside. I tried it at work on Friday and it works really well. Here are two videos, one of the finished wand, and the other showing the reeling mechanism.

[youtube]HKoXQt6RKJg[/youtube]

[youtube]6YGut9aDxoc[/youtube]

I hope this'll give you ideas for your own telescopic wand.

Take care yall!
« Last Edit: March 09, 2009, 02:27:55 AM by Fastolfe »



Offline mystre

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Reply #1 on: March 08, 2009, 04:51:16 PM
I'm making something similar - but for 1st graders   :P 



Offline broorb

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Reply #2 on: March 08, 2009, 10:45:38 PM
I attempted to create one last weekend using a TV antennae as a telescopic tube.  It gets very narrow near the end though, so I ended up  "parking" the project until I can find a ready made telescopic stick that is not too narrow at the end where I can run a single wire (+) and use the tube as the gound (-).  I am still looking for a professional looking telescopic stick that is being used the classrooms.  Can you please point me to the url for the expandable phone charger that you used ?   :)

Thanks!
-broorb



Offline Fastolfe

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Reply #3 on: March 09, 2009, 01:58:10 AM
I'm not too sure which brand of cell phone charger it is, as it was a flea market find, but it looks very much like this one here:


(http://cellphonestuff.south1.net/retractable-cord-car-charger-for-lg-vx5200/).

The cord is no more than 1mm in diameter, thin enough to go through the top tube of my pointer, which is very thin indeed. I believe most such retractable cord devices have thin cords, as they need to be flexible enough to be reeled onto the spool with only a light spring tension.

The cord has two wires in it (+ and -) so you don't have to rely on the telescopic tube to act as a ground. That's one less sliding contact to go wrong. The + and - wires are quite thin though, so I suggest you don't drink too much coffee when soldering them to the LED.

Good luck with your project!

I attempted to create one last weekend using a TV antennae as a telescopic tube.  It gets very narrow near the end though, so I ended up  "parking" the project until I can find a ready made telescopic stick that is not too narrow at the end where I can run a single wire (+) and use the tube as the gound (-).  I am still looking for a professional looking telescopic stick that is being used the classrooms.  Can you please point me to the url for the expandable phone charger that you used ?   :)



Offline broorb

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Reply #4 on: March 09, 2009, 03:55:13 AM
woah .. this is nice.  I didn't think about retractable wires before.  Now that you mentioned it, I think I will be able to use this on my wand.  I was able to get some good retractable pointers from DealExtereme today. Here''s the link:

http://www.dealextreme.com/details.dx/sku.5597

Thank you for sharing a great idea Fastolfe !  :)

-broorb



Offline isashach

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Reply #5 on: March 09, 2009, 03:41:09 PM
I was actually expecting something where you press a button and it all goes back in like in my car charger....