Overview

The VL6180X from ST Microelectronics is a sensor that combines proximity ranging and ambient light level measurement capabilities into a single package. This board is a carrier for the VL6180X, so we recommend careful reading of the VL6180X datasheet (2MB pdf) before using this product.

Unlike simpler optical sensors that use the intensity of reflected light to detect objects, the VL6180 uses ST’s FlightSense technology to precisely measure how long it takes for emitted pulses of infrared laser light to reach the nearest object and be reflected back to a detector, making it essentially a short-range lidar sensor. This time-of-flight (TOF) measurement enables it to accurately determine the absolute distance to a target with 1 mm resolution, without the object’s reflectance influencing the measurement. The sensor is rated to perform ranging measurements of up to 10 cm (4?), but it can often provide readings up to 20 cm (8?) with its default settings. Furthermore, the VL6180X can be configured to measure ranges of up to 60 cm (24?) at the cost of reduced resolution, although successful ranging at these longer distances will depend heavily on the target and environment. (For more information, see “Range scaling factor” below.)

The VL6180 also includes an ambient light sensor, or ALS, that can measure the intensity of light with which it is illuminated. Ranging and ambient light measurements are available through the sensor’s I²C (TWI) interface, which is also used to configure sensor settings, and two independently-programmable GPIO pins can be configured as interrupt outputs.

The VL6180X is a great IC, but its small, leadless, LGA package makes it difficult for the typical student or hobbyist to use. It also operates at voltages below 3 V, which can make interfacing difficult for microcontrollers operating at 3.3 V or 5 V. Our breakout board addresses these issues, making it easier to get started using the sensor, while keeping the overall size as small as possible.

Specifications

• Dimensions: 0.5? × 0.7? × 0.085? (13 mm × 18 mm × 2 mm)
• Weight without header pins: 0.5 g (0.02 oz)
• Operating voltage: 2.7 V to 5.5 V
• Supply current: 5 mA (typical; varies with configuration, target, and environment)
• Output format (I²C): 8-bit distance reading (in millimeters), 16-bit ambient light reading
• Distance measuring range: up to 10 cm (4?) specified; up to 60 cm (24?) possible with reduced resolution. See the graph at the right for typical ranging performance.
  • Ranging beyond 10 cm is possible with certain target reflectances and ambient conditions but not guaranteed by specifications. By default, the sensor can report distances up to 20 cm, or it can be configured to measure up to 60 cm with reduced resolution.
  • The datasheet does not specify a minimum range, but in our experience, the effective limit is about 1 cm.

Included components

A 1×7 strip of 0.1? header pins and a 1×7 strip of 0.1? right-angle header pins are included, as shown in the picture below. You can solder the header strip of your choice to the board for use with custom cables or solderless breadboards, or you can solder wires directly to the board itself for more compact installations.

The board has two mounting holes spaced 0.5? apart that work with #2 and M2 screws (not included).

Using the VL6180X

Connections

A minimum of four connections is necessary to use the VL6180X board: VIN, GND, SCL, and SDA. The VIN pin should be connected to a 2.7 V to 5.5 V source, and GND should be connected to 0 volts. An on-board linear voltage regulator converts VIN to a 2.8 V supply for the VL6180X IC.

The I²C pins, SCL and SDA, are connected to built-in level-shifters that make them safe to use at voltages over 2.8 V; they should be connected to an I²C bus operating at the same logic level as VIN.

The two GPIO pins are open-drain outputs pulled up to 2.8 V by the board (although GPIO0 defaults to being a chip enable input). They are not connected to level-shifters on the board and are not 5V-tolerant, but they are usable as-is with many 3.3 V and 5 V microcontrollers: the microcontroller can read the sensor’s output as long as its logic high threshold is below 2.8 V, and the microcontroller can alternate its own output between low and high-impedance states to drive the pin. Alternatively, our 4-channel bidirectional logic level shifter can be used externally with those pins.

Pinout