Oh BTW, the IR is probably pulsed at 38,400 Hz like a TV remote. Steady IR doesn't effect the readers except if they wash the signal out.I have IR detectors that look like black leds with 2 leads, the light is the bias. The black in the bulb filters regular light very well but not reflected IR. If I put the bulb in even a short tube, it won't 'see' much more than a signal led, get less scattered interference. You won't have to modify the meter.