I'm trying to develop a device that can detect or "watch" an infrared beacon that is freely moving side-to-side anywhere within a 180° field of view (-90° to +90°, with center/forward at 0°); i.e. the sensor should see the beacon if it is directly to the left (-90°), to the right (+90°), or anywhere inbetween, but not if the beacon is anywhere behind the sensor.
I've glued a little IR sensor (TSOP38238) on top of a micro servo (Tower Pro SG92R), and I have these wired up to a Circuit Playground Express with CRICKIT. I'm programming on the board via Arduino, and the software seems to be working great -- the servo will continuously sweep the full field of view, and if the specific IR signal I'm transmitting (38kHz, NEC IR protocol with 32-bit payload data) is received by the sensor, the servo's current position/angle is logged immediately.
However, my problem is restricting the IR sensor's vision. For example, if the servo with IR sensor are facing left (-90°), and the IR signal is being transmitted from front and center (0°), the IR sensor detects that signal and thus determines that the source of the signal came from the left (-90°). This example is real and practical, but the problem is in fact far worse; the sensor is detecting IR transmissions from all 360° -- there is no direction the servo and IR sensor can face that it will not detect the source IR signal being transmitted!
The only thing I know to do is to fabricate blinders to surround the IR sensor. If I can somehow block (reflect, absorb, whatever) any IR signal to which the sensor does not have a direct line-of-sight, then it should help prevent these undesirable signals. Or even if I can't block the signal, perhaps it's possible to corrupt it to cause a change in frequency or payload data.
I've constructed some blinders using craft sticks and super glue, with several layers of aluminum foil (like you use in the kitchen) taped to the outside. I added the aluminum because of this SE thread I found. But still, the IR signals seem to pass right through.
So what other techniques or materials are possible here to restrict IR signals to line-of-sight?
The blinders I constructed look like the following. The wooden side faces the inside (faces the IR sensor), aluminum side faces outward (faces the world):
And the following is how the blinders are mounted onto the servo, with the IR sensor inbetween. The intent is to blind signals coming from the sides, but still allow the signals to reach the sensor if coming from different heights: