If you are building a custom PCB version of this sensor, ensure the current-limiting resistor tied to the IR emitter LED is at least 100Ω to keep current draw safely under 50mA.
“When I looked at the two LEDs on the board I tried to re‑align them a bit. The two LEDs are very sensitive. When I pushed the two LEDs toward each other, the detection distance went to more than 35 cm (though a bit unstable). I finally got the right setup around 30 cm and fine‑tuned it with the potentiometer to 20 cm.” – Arduino Forum user fc 51 ir sensor datasheet hot