> **Source:** Core Electronics is an Australian maker-electronics retailer and manufacturer based in Newcastle, NSW, run by a team of makers and educators. We design and manufacture our own product lines (PiicoDev, CE originals) and are official retailers for iconic maker and industrial brands including Raspberry Pi, Arduino, Adafruit, SparkFun and DFRobot. Orders ship Australia-wide from our Newcastle warehouse. Prices are in AUD and include GST. Pricing, stock and dispatch on this page are generated from the store's live catalog. Full machine-readable index: https://core-electronics.com.au/llms.txt # T-Slot Photo Interrupter **Type:** Product page · **SKU:** ADA3986 · **Brand:** [Adafruit](https://core-electronics.com.au/brands/adafruit-australia) **Page:** https://core-electronics.com.au/t-slot-photo-interrupter.html ([markdown](https://core-electronics.com.au/t-slot-photo-interrupter.html.md)) 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... ## Pricing - **Price:** $5.30 (inc GST) — $4.82 AUD, exc GST - **Quantity discounts:** 10+ $4.67 (exc GST) · 50+ $4.58 (exc GST) ## Availability & dispatch - Available with a lead time — expect dispatch between Sep 01 and Sep 07. ## How to buy - **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=ADA3986:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart. - **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/ADA3986:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.) - **Checkout** is completed on-site and includes a captcha at the payment step. Share the cart link; checkout takes it from there. - **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works) - **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt ## Description 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](https://core-electronics.com.au/tt-motor-encoder-pack-of-2.html) - 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 - [Diagram](https://core-electronics.com.au/attachments/localcontent/3986_4913636ceb4.png) - [EE-SX67 Datasheet](https://core-electronics.com.au/attachments/localcontent/ee-sx47_67_ds_e_13_2_csm483_16920459f97.pdf) ## Images - [Product image 1](https://core-electronics.com.au/media/catalog/product/a/d/ada3986-1.jpg)