Modulation at a few kHz should solve that.  NIR pass filter on sensor.
You could even send a code like a keychain remote code, making it very unli=
kely that a natural source will fool you.

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO =A080301 USA
phone:=A0303-417-1345 =A0x110
email:=A0david.vanhorn@backcountryaccess.com=A0



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