T-Slot Photo Interrupter

SKU: ADA3986 Brand: Adafruit

This T-Slot Photo Interrupter is a simple plastic sensor with two elements - an IR LED and an IR photo-transistor, situated across a U-shaped gap. You can control...

$5.90 AUD, inc GST

$5.36 AUD, exc GST

In stock, ships same business day if ordered before 2PM
Delivered by Fri, 6th of Dec

Quantity Discounts:

10-25 $5.20 (exc GST)
25+ $5.09 (exc GST)

This T-Slot Photo Interrupter is a simple plastic sensor with two elements - an IR LED and an IR photo-transistor, situated across a U-shaped gap. You can control the IR LED and turn it on to transmit IR light across the gap, to the detector on the other side. This makes it perfect for detecting when something is in the slot - when there's something blocking the light, the sensor turns off, when the object goes away, the sensor receives the IR light and turns on.

These sensors are handy when you want to detect if something has passed through the sensor slot, we think it's great when paired with Adafruit's slotted encoder wheels - as you can see Adafruit have a demo that will count the number of transitions (slots) over a second, extrapolate that to RPM, and display on an OLED. This sensor is extra fancy with a red LED on the side to let you know when the sensor is triggered, and built in protection circuitry.

Adafruit will mention the one down-side to this sensor is that the circuitry inside has power requirements - the Vin line must be powered by at least 5V. But, the output transistor is open-collector so you can connect a pullup resistor to 3V for 3.3v logic if you need. So, as long as you have some 5V power output, you can use it with a 3V device like the Feather shown in the demo.

This version does not have a cable attached, but it does have nicely labeled pads.

(+) symbol - VCC (logic circuit power 5-24V)
L - LED configuration, see datasheet for options but Adafruit just tie to VCC
OUT - transistor output. Open collector so you must connect a pullup resistor to your logic level.
(-) symbol - Ground

Technical Details

Weight: 2g
Gap width: 5mm
Sensing distance: 5mm
Light source: Infrared LED (940 nm)
Power supply voltage: 5 to 24 VDC ±10% (ripple (p-p)10% max.)
Current consumption: 35 mA max
Control output (output type): NPN Open collector output
Control output (load power supply voltage): 5 to 24 VDC
Control output (load current): 100 mA max
Response frequency elements: 1 kHz min. (average 3 kHz)
See the datasheet for more information and dimensional diagrams, this is equivalent to part #EE-SX672

This optoreflector tutorial might be handy for understanding how these sensors work

This product is listed in:

Sensors>Infrared

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