PING PONG BALL.

Sensor looks up at ball from about 2" distance (depending
on sensor beamwidth).
Diffuse white surface reflects impinging beam into
sensor field of view.
You loose some range, but it works MUCH better than a polished
steel ball bearing (which I also tried).
The b/b gives you a tiny specular reflection. The white ball
gives a a large area the sensor more readily sees.

I use half balls on my living room stereo gear so I can hit it
with the remotes from the workroom, at a 180 degree angle.

Forums wrote:

> Cedric Chang wrote:
> 
> 
>>Another thing that might help is a space blanket, real thin material
>>$2-$3 at Walmart.
> 
> 
> Yeah, those are made of PET film, better known under a trade name 'Mylar'.
> NASA have used the stuff on satellites and landers etc. to reflect heat from
> the sun. A single sheet will reflect 90%+ of IR.
> 
> You can also get it from party shops, in the form of a gold or silver gift
> wrap... but if it tears easily, it's not PET.
> 
> One concern here is I would expect the reflection to be very directional
> just like the visible light is, so making it mirror-flat might not be
> perfect for what you are trying to do. A laser pointer might be useful to
> get the angles correct for a specific situation, and most video cameras are
> sensitive to IR (not extremely, but enough to see the light from a remote
> control) so it might be a useful calibration tool.
> 
> Andy
> 
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