Hi guys , looking for input on the correct selection of IR LED and IR receiver module combination , in that i want to send a constant pulse stream of high at 800ns / low at 1.4us modulated to 38Khz , the requirement is to be a fine focus ir stream to IR receiver module over about 20 meters in outdoor open area during day conditions . where interruption after focus to stream is noted by system

Questions / assumptions .

IR LED selection:
1. IR led selection be one with a narrow degree angle so as to ensure a fine focus to IR reciever - 10deg or lower at 3deg
2. rise / fall time ability of the LED to need to be less than 800ns - typicaly thinking about 20 - 50ns or there about
3. peek wave length of IR LED should match IR receiver module selected or visa versa
4. high radiant intensity , typicaly 1000mw/sr or higher ? given distance and expected outdoor environment issues ?

IR receiver Module Selection
1. peek wave length of IR LED should match be the same as IR receiver selected or visa versa
2. transmission distance should be typically 20 meters or better
3, internal filter for a 38Khz Ir signal
4. visable light suppression by ir filter , given useage
5. Receptivity / angle of half transmission distance +/- 45Deg ( this seems to be standard for most Ir modules i have looked at )

Notes.
When looking at peek wavelength vs spectral sensiivity graphs of IR reciever , the " sweet spot" should be middle of top end of the curve - correct ???

cheers
sheldon