SparkFun Distance Sensor Breakout - RFD77402 (Qwiic)

The SparkFun Distance Sensor Breakout utilizes the RFD77402 3D ToF (Time of Flight) sensor module from Simblee to give you the most accurate measurements at short range. The RFD77402 uses an infrared VCSEL (Vertical Cavity Surface Emitting Laser) module to measure the amount of time it takes to bounce off a target. This allows low-cost millimeter readings up to two meters! To make it even easier to use this breakout, all communication is enacted exclusively via I2C, utilizing our handy Qwiic system. However, we still have broken out 0.1" spaced pins in case you prefer to use a breadboard.

Thanks to the RFD77402’s 850nm VCSEL and electronic driver and optical receiver sensor, this breakout is ideal for distance measurements ranging from 100mm to 2000mm, 1D gesture recognition, obstacle detection and avoidance in robotics applications, and more! The RFD77402 utilizes an I2C interface that supports a direct 8-bit addressing scheme to access the module user’s register set and an additional 16-bit indirect addressing scheme that is mainly used for debugging purpose or special operations.


The SparkFun Qwiic Connect System is an ecosystem of I2C sensors, actuators, shields and cables that make prototyping faster and less prone to error. All Qwiic-enabled boards use a common 1mm pitch, 4-pin JST connector. This reduces the amount of required PCB space, and polarized connections mean you can’t hook it up wrong.


Note: CLASS 1 LASER PRODUCT CLASSIFIED IEC 60825-1 2014.

Get Started with the Qwiic RFD77402 Breakout Hookup Guide

  • Operating Voltage 3.3V
  • Current 7 mA average at 10Hz
  • Measurement Range: ~50mm to 2,000mm
  • Precision: +/-10%
  • Light Source: 850nm VCSEL
  • I2C Address: 0x4C
  • Field of View: 55°
  • Field of Illumination: 23°
  • Max Read Rate: 10Hz (We’ve seen up to 20Hz in practice)
  • 2x Qwiic Connection Ports

SparkFun Distance Sensor Breakout - RFD77402 (Qwiic) Product Help and Resources

Qwiic Distance Sensor (RFD77402) Hookup Guide

April 5, 2018

The RFD77402 uses an infrared VCSEL (Vertical Cavity Surface Emitting Laser) TOF (Time of Flight) module capable of millimeter precision distance readings up to 2 meters. It’s also part of SparkFun’s Qwiic system, so you won’t have to do any soldering to figure out how far away things are.

Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

3 Programming

Skill Level: Competent - The toolchain for programming is a bit more complex and will examples may not be explicitly provided for you. You will be required to have a fundamental knowledge of programming and be required to provide your own code. You may need to modify existing libraries or code to work with your specific hardware. Sensor and hardware interfaces will be SPI or I2C.
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Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

2 Electrical Prototyping

Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
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Customer Comments

  • Easy to setup and use, but I’m seeing +/- 6mm when 250 mm away… so don’t expect a solid reading.

    • What is the object you are detecting the distance from out of curiosity?

      • I tried it with several different objects to start, but for the final testing I used a white wall. Actually, if you look at your hookup guide, you’ll even see similar numbers in the screenshots there… I just didn’t catch that detail when I was reading it…

  • Could this be used as a water level sensor, or would the signal just go through the water?

    • I’ve seen the Lidar Lite go through glass. Depends on the attenuation coefficient for water at the wavelength, but in general it’s not 100% for near ir. I would go with sonar for measuring water level. You could also float a reflector of appropriate material on the surface of the water if you want to use ir or are concerned about the wide beam angle from sonar.

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