PMW3901 Optical Flow Sensor

PMW3901 Optical Flow Sensor Breakout

This fantastic optical flow sensor is capable of detecting movement across surfaces placed in front of it. Its detection range goes from ~80mm to infinity. You can use it for your DIY drone projects, and it is also compatible with the new Breakout Garden HAT with SPI.

This brilliant PMW3901 sensor uses a low-resolution camera together with several algorithms to detect surface movement. It is particularly impressive when used, for example, to correct drone drift by detecting the x/y movement of the ground below.

PMW3901 Optical Flow Sensor Breakout Features

• PMW3901 optical flow sensor
• Two onboard white LEDs for illumination
• Frame rate: 121 FPS (frames per second)
• Speed: 7.4 rad/s (radians per second)
• Field of view: 42°
• Range: ~80mm to infinity
• Typical current consumption: 6mA
• SPI interface
• It is 3.3V or 5V compatible
• Reverse polarity protection
• Compatible with Arduino and all models of Raspberry Pi
• Python library

Software
You can use the Python library for the Optical Flow Sensor Breakout. Thanks to it, you will be able to read x/y movement values and their magnitude very easily.

Connecting to Raspberry Pi
If you are not using the Breakout Garden HAT with SPI, carefully read the instructions below to connect the Optical Flow Sensor Breakout to your Raspberry Pi.

The library is configured to use SPI 0 on the Raspberry Pi: BCM 8 for CS, BCM 11 for SCK, BCM 10 for MOSI, BCM 9 for MISO, and BCM 18 for the INT pin.

Check below which pins to connect between the Optical Flow Sensor Breakout and your Raspberry Pi GPIO (please note that the pins use BCM numbering):

• 3–5V to any 5V or 3V pin
• CS to BCM 8
• SCK to BCM 11
• MOSI to BCM 10
• MISO to BCM 9
• INT to BCM 18
• GND to any ground pin

You can still use different pins with your MISO connected to BCM 9, but remember to change them accordingly when you instantiate the sensor in your code.

Notes
Dimensions: 24x24x5mm

Pimoroni name: PMW3901 Optical Flow Sensor Breakout [PIM453]