Review on Infrared Obstacle Avoidance Sensor Arduino by Runbi Alvarez

There are two problems with these modules: 1. They only have a 100 ohm resistor between Vcc and the LED. This is way too low and explains why a lot of people complain about LEDs burning out with continuous use at 5V. I'm pretty sure this is normal at 3.3V.2. The transmitter and receiver are in close proximity to each other and there is no "protection" between them. Thus, the receiver tends to register false positive readings. If you put a sheet of paper or plastic in between I'm sure it will work just fine. So at 3.3V and with a home made optical shield between transmitter and receiver they work fine. However, IR modules are available from Revain with a different design that solves both of these problems - they have a higher resistance so the LED works fine at 5VDC, and they have a built in plastic shield between the emitter and receiver.