VL53L5CX Time of Flight (ToF) breakout and MicroPython

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2022-08-11 | By Pimoroni

License: See Original Project Time-of-Flight (ToF)

Courtesy of Pimoroni

Guide by Pimoroni

This super quick guide will show you how to use our new VL53L5CX distance ‎sensor breakout with a Raspberry Pi Pico (or other RP2040 board) using ‎pirate brand MicroPython.‎

About VL53L5CX

VL53L5CX is a fancy new Time of Flight (ToF) distance sensor from ‎STMicroelectronics. It can do fast and accurate multizone ranging - find out ‎more about its vital statistics on the shop page!‎

The firmware for this sensor is rather large, so we've not included it into our ‎MicroPython build as standard - you'll need to download it separately and ‎copy it across using Thonny. We'll show you how to do that here, but If you're ‎brand new to Pico/RP2040 microcontrollers you might also find our beginner ‎friendly Getting Started with Raspberry Pi Pico guide useful.‎

Installing MicroPython

Download the most recent MicroPython .uf2 from the Releases page of ‎our pimoroni-pico Github repository (you'll need v1.18.8 or later). For ‎most boards, you'll want the generic Pico .uf2:‎

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Hold down the BOOT button of your microcontroller, and then plug in ‎the USB cable (or tap the RESET button if you have one). This will put it ‎into bootloader mode, and it should appear as a drive on your computer ‎called RPI-RP2.‎
Copy the .uf2 file to the RPI-RP2 drive and your microcontroller will ‎reboot running MicroPython. From now on, it won't show up as a drive, ‎you'll need to use an interpreter (Thonny) to program it.‎

Installing Thonny

• Download and install Thonny. It's available for Windows, Mac, and ‎Linux.‎

• Open up Thonny. Make sure the interpreter (shown in the box on the ‎bottom right corner) is set to 'MicroPython (Raspberry Pi Pico)' and that ‎the 'Files' window is visible (if not, it's under 'View > Files'). If set up ‎correctly, it should look something like this:‎

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If you don't see the MicroPython prompt in the 'Shell' box, try pressing the ‎‎'stop' button to interrupt whatever your microcontroller is doing.‎

Installing VL53L5CX Firmware

Download the VL53L5CX firmware.‎
Navigate to the .bin file using the top 'Files' box in Thonny. Right click ‎on it and select 'Upload to /' to save it to your Pico.‎

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Note that the .bin firmware file must be named 'vl53l5cx_firmware.bin' and it ‎must be in the root directory of your microcontroller's filesystem.‎

Running the Examples

You can find the MicroPython VL53L5CX examples here. Copy and ‎paste one into Thonny and press the green 'run' button to run it on your ‎Pico (you'll be prompted to give it a filename if you haven't run it ‎before).‎
Wiggle your fingers in front of the sensor to check that it's working!‎

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Using Alternate I2C Pins

Most boards use GP4 and GP5 as the I2C pins for their Breakout Garden slots ‎and Qw/ST connectors so our examples will assume you're using those pins ‎by default. However, the Breakout Garden slots on Pico Explorer Base (and ‎the Qw/ST connectors on some of our more crowded RP2040 boards, ‎like Interstate 75, Plasma 2040, and Servo 2040) use alternate I2C pins - ‎GP20 and GP21.‎

If you have a board that uses the alternate pins you'll need find this line in ‎your code:

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i2c = pimoroni_i2c.PimoroniI2C(**PINS_BREAKOUT_GARDEN, baudrate=2_000_000)‎

and change it to:‎

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i2c = pimoroni_i2c.PimoroniI2C(**PINS_PICO_EXPLORER, baudrate=2_000_000)‎

Next Steps

We mounted one of these breakouts on the front of a tiny Raspberry Pi Pico-‎powered robot we made using our new Motor SHIM for Pico and adapted the ‎object tracking example to get it to follow a business card on a stick. Here is ‎BusinessBot in action!‎

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