2 Sets 50Pcs LEDs Infrared Emitter and IR Receiver Diode 5mm 940nm Infrared Emission and Receiver Diode(100Pcs in Total)[Light Emitting diodes (LEDs)]

I am very happy with this item.I ordered these for experimenting with object detection for a DIY security system. They are pretty run of the mill LEDs but I've used about half of both the emitters and the receivers and they've all worked perfectly in my application.They fit in panel mount holders like they're supposed to and the leads are cut to correctly identify the polarity.I'd definitely recommend these. They're working great for me.

I got these for creating a device to measure the speed of thrown objects. The LEDs and diodes work great. The voltage across the black diode changes depending on the amount of IR light it receives, so you can easily hook it up to a microcontroller such as an Arduino to record when the change takes place which means an object is blocking the sensors. Two of these pairs will allow you to record the time between changes in voltage of each sensor pair, and thus with the known distance between them, you can find the speed of the object. The package contains a generous amount of LEDs and diodes for the price, overall a great buy.