Author Topic: [Help]What's wrong with my IR pen?  (Read 5002 times)

Offline StrongZhu

  • *
  • Posts: 3
  • Karma: +0/-0
    • View Profile
on: May 02, 2008, 05:18:42 AM
dear all

  I bought a IR LED without knowing it's type. The saler told me that it is very common, and will work under 1.3V, 18mA.
  I connected it with a 1.5V battery and 10ohm resistor.
  The Wii remote did detecte the IR point.

  The problem is that, when I increase the distance between IR LED and the wii remote, (e.g. more than 1-2 meter), The wii remote CANNOT detect anything.....

  Then I shut down all the lamps in the room, and using the USB webcam to detect the IR LED. The image from USB webcam shows a light point even if the distance is more than 3-4 meters.
  Further more, while I put the wii remote near the IR LED(less than 50cm), if i rotate the IR LED with certain angle(e.g. less than 30 degree), the wii remote CANNOT detect anything.... which means I must point the IR pen almost exactly to the IR camear in wii remote. It's inconvenient for using it in a whiteboard. 
  So, what's the detail of IR LED which is working in your IR pen?
  Can it emit IR light to all the direction?
  Thanks a lot.

« Last Edit: May 02, 2008, 05:21:38 AM by StrongZhu »

Offline StrongZhu

  • *
  • Posts: 3
  • Karma: +0/-0
    • View Profile
Reply #1 on: May 02, 2008, 05:24:59 AM
The image in attachment shows the region which can be detected by wii remote

white means CAN be detected.
black means CANNOT be detected.

Offline benpaddlejones

  • Support Admin
  • *
  • Posts: 1178
  • Karma: +49/-0
    • View Profile
    • Inter.Connect.Ed
Reply #2 on: May 06, 2008, 07:54:36 AM
Your IR-LED has an acute viewing angle!

See my topic:

It shows a few pictures of different angles of a IR-LED with a 25 degree (acute) viewing angle. You will see no chance of being detected from any wider angle.

I think the only way to go is the Vishay TSAL6400s as used by JCL it has a viewing angle of 50 degree's and is very strong 100ma.

Vishay's website is: on their site is listed international distributors. You need to find the distributor in your country then find the closest retail outlet.

Being Australian myself this was quite a process with as I found out today the retail outlet doesn't always know their own suppliers. They thought it was a Vishay but as the photo's show it's viewing angle is far less than 50 degree's.

I have just found a British/Australian (go figure, our royal bonds are hard to break, but convenient) electronic components distributor that quotes parts by the manufactures part number. So hopefully I have 5 Vishay TSAL6400s in the post.


See my full profile and links on my Google Profile: