TCRT5000 Sensor

Vishay TCRT5000 reflective optical sensor on a breakout board — the canonical IR photoelectric switch for 3D-printer filament runout sensing, endstops, encoder wheels, and line-following projects. Sold individually for repairs, custom builds, or to upgrade an existing kit.

Why the TCRT5000 instead of an endstop microswitch

• Non-contact: the filament never mechanically actuates a lever, so no wear on switches or springs over thousands of cycles.
• Detects a wide range of materials — opaque PLA, PETG, ABS, PETG-CF, PA-CF, PLA-AERO, even translucent PETG when the threshold is dialed correctly.
• Analog + digital output — the analog pin lets Klipper or Marlin map signal strength for advanced sensing (e.g. ERCF toolhead sensor uses the analog curve to detect the leading edge of the filament tip before the print is interrupted).
• Inexpensive enough to spec per-toolhead — multi-material and ERCF builds need one per toolhead.

Specifications

• Sensor IC: Vishay TCRT5000 (IR LED 950 nm + phototransistor in one package)
• Supply voltage: 3.3 V – 5 V DC
• Current draw: ~10 mA typical (LED on)
• Sensing distance: ~0.5 – 15 mm depending on surface reflectance
• Outputs: AO (analog, 0 – Vcc) and DO (digital, threshold set by on-board trimpot)
• Output indicator: on-board LED lights on detection
• Header: 4-pin 2.54 mm (Vcc / GND / DO / AO)
• PCB dimensions: ~32 × 14 mm
• Mounting: two 3 mm through-holes on 28 mm centers

Intended use / machine fitment

• ERCF (Enraged Rabbit Carrot Feeder) toolhead sensor — this is the sensor board the ERCF Toolhead Sensor Kit and the Binky ERCF encoder are designed around. If you need a replacement, this is it.
• Filament runout sensor for Voron, Ender 3, Prusa MK-series, RatRig, and any printer running Klipper or Marlin with a generic GPIO/analog input.
• Bed probe / endstop for optical applications (note: not a substitute for a precision probe like Voron Tap or PCB Klicky).
• Encoder / tachometer for spool rotation sensing on direct-drive extruders.
• Line-following and robotics outside of 3D printing — works fine on 5 V Arduino / Raspberry Pi Pico projects.

What this is — and what it isn't

• This is a breakout module (the TCRT5000 IC on a small carrier PCB with header pins and a sensitivity trimpot), not the bare IC. If you need a surface-mount component for a custom PCB, source the IC directly from an authorized distributor.
• Not a precision probe. Reflective sensing is great for filament presence but lacks the repeatability of a tactile probe for mesh bed leveling. Use the right tool for the job.
• Not invisible to clear filament. Fully transparent PC or TPU will not trigger reliably without a contrast marker or a different sensor type. For most common 3D-printer filaments the TCRT5000 works out of the box.