Hello Mc Curty
First , be sure you're talking about a SFH487P , not SFH487 (notice the trailing P). They're not the same devices
The SFH487P is a wide beam angle IR led, the SFH487 is a narrow beam angle IR led (20° half angle).
It's easy in a shop to ask for a SFH487 when you want a 487P , so be careful.
I personnally don't recommend using the SFH487P, bcause they're only 3 mm leds (the SFH485P are 5mm leds).
You're right about the angle, the SFH487P has a better half angle than the SFH485P (65° vs 40°) but :
- angle is given at half light power, so at 40° from it's center, the SFH485P still emits IR (it's not as if the led was black at this angle).
- at 40° from the angle, YOU (user) will have big difficulties to look at your screen
. So you definitely don't need more angle. (IMO)
- As i told, the SFH487P is smaller than the SFH485P. this negates somehow this angle advantage since the IR dot is smaller.
IMO, SFH485P are better suited for Freetrack, despite the wider beam angle of the SFH487P.
cya