IR Proximity sensor
When using IR method to detect human pass by,TX/RX put side by side,
reflection type without using reflector, what is the max practical range I
can get? Right now I can only get 1 meter, can the range be increase without using reflector?
My target is at least 2meter. Can it be done?
using the burst method might help. i assume ur emitter is an IR diode. pulse a high current(ref: datasheet) through the diode for a very short duration .
It's NOT a good method, IR reflection is highly dependent on the object doing the reflecting - if you're getting reliable 1m range from normally dressed people I would suspect that's probably good going?.
Dress the people in shiny foil, and you should make 5 or 6m.
It's more common to use ultrasonics for this, and doppler shift changes, or (better still) is microwave radar - which is what you usually find on automatic shop doors.
A cheap PIR detector from RadioShack picked up normally dressed people over a wide area at a distance of 12m easily. It detects movement from their heat and doesn't radiate IR itself.
Cheap motion detectors for outdoors houselights also have a pretty good range.