Chain ToF

ToFChain is the helper class for ToF (Time of Flight) sensor devices on the Chain bus. It provides methods to read distance measurements, configure measurement parameters (time, mode, status), and check measurement completion status.

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UiFlow2 Example

Distance measurement display

Open the m5core_chain_tof_basic_example.m5f2 project in UiFlow2.

This example demonstrates how to read distance measurements from the Chain ToF sensor and display them on screen. The example configures the sensor for continuous measurement mode and updates the distance value in real-time.

UiFlow2 Code Block:

Example output:

None

MicroPython Example

Distance measurement display

This example demonstrates how to read distance measurements from the Chain ToF sensor and display them on screen. The example configures the sensor for continuous measurement mode and updates the distance value in real-time.

MicroPython Code Block:

# SPDX-FileCopyrightText: 2025 M5Stack Technology CO LTD
#
# SPDX-License-Identifier: MIT

import os, sys, io
import M5
from M5 import *
from chain import ChainBus
from chain import ToFChain
import time



title0 = None
label_dis = None
bus2 = None
chain_tof_0 = None
last_time = None
distance = None


def setup():
    global title0, label_dis, bus2, chain_tof_0, last_time, distance

    M5.begin()
    Widgets.setRotation(1)
    Widgets.fillScreen(0x222222)
    title0 = Widgets.Title("Chain ToF Example", 3, 0xffffff, 0x0000FF, Widgets.FONTS.DejaVu24)
    label_dis = Widgets.Label("Distance: --", 20, 92, 1.0, 0xffffff, 0x222222, Widgets.FONTS.DejaVu24)

    bus2 = ChainBus(2, tx=21, rx=22)
    chain_tof_0 = ToFChain(bus2, 1)
    chain_tof_0.set_rgb_color(0x33ccff)
    chain_tof_0.set_rgb_brightness(10, save=False)
    chain_tof_0.set_measure_mode(ToFChain.MODE_CONTINUOUS)


def loop():
    global title0, label_dis, bus2, chain_tof_0, last_time, distance
    M5.update()
    if (time.ticks_diff((time.ticks_ms()), last_time)) >= 200:
        last_time = time.ticks_ms()
        distance = chain_tof_0.get_distance()
        label_dis.setText(str((str('Distance: ') + str(((str(distance) + str(' mm')))))))


if __name__ == '__main__':
    try:
        setup()
        while True:
            loop()
    except (Exception, KeyboardInterrupt) as e:
        try:
            bus2.deinit()
            from utility import print_error_msg
            print_error_msg(e)
        except ImportError:
            print("please update to latest firmware")

Example output:

None

API

ToFChain

class chain.tof.ToFChain(bus, device_id)

Bases: KeyChain

ToF Chain class for interacting with ToF (Time of Flight) devices over Chain bus.

Parameters:

• bus (ChainBus) – The Chain bus instance.

• device_id (int) – The device ID of the ToF sensor on the Chain bus.

UiFlow2 Code Block:

MicroPython Code Block:

from chain import ChainBus
from chain import ToFChain

bus2 = ChainBus(2, tx=21, rx=22)
chain_tof_0 = ToFChain(bus2, 1)

get_distance()

Get the distance measurement.

Returns:

Distance in millimeters, or None if failed.

Return type:

int

UiFlow2 Code Block:

MicroPython Code Block:

distance = chain_tof_0.get_distance()

set_measure_time(time_ms=33)

Set the measurement time.

Parameters:

time_ms (int) – Measurement time in milliseconds. Range: 20-200, default: 33.

Returns:

True if the operation was successful, False otherwise.

Return type:

bool

UiFlow2 Code Block:

MicroPython Code Block:

success = chain_tof_0.set_measure_time(33)

get_measure_time()

Get the measurement time.

Returns:

Measurement time in milliseconds, or None if failed.

Return type:

int

UiFlow2 Code Block:

MicroPython Code Block:

time = chain_tof_0.get_measure_time()

set_measure_mode(mode=2)

Set the measurement mode.

Parameters:

mode (int) – Measurement mode. Use ToFChain.MODE_STOP (0), ToFChain.MODE_SINGLE (1), or ToFChain.MODE_CONTINUOUS (2). Default: 2.

Returns:

True if the operation was successful, False otherwise.

Return type:

bool

UiFlow2 Code Block:

MicroPython Code Block:

success = chain_tof_0.set_measure_mode(ToFChain.MODE_CONTINUOUS)

get_measure_mode()

Get the measurement mode.

Returns:

Measurement mode. ToFChain.MODE_STOP (0), ToFChain.MODE_SINGLE (1), or ToFChain.MODE_CONTINUOUS (2). Returns None if failed.

Return type:

int

UiFlow2 Code Block:

MicroPython Code Block:

mode = chain_tof_0.get_measure_mode()

set_measure_status(status)

Set the measurement status.

Parameters:

status (int) – Measurement status. 0 means not measuring, 1 means measuring.

Returns:

True if the operation was successful, False otherwise.

Return type:

bool

UiFlow2 Code Block:

MicroPython Code Block:

success = chain_tof_0.set_measure_status(1)

get_measure_status()

Get the measurement status.

Returns:

Measurement status. 0 means not measuring, 1 means measuring. Returns None if failed.

Return type:

int

UiFlow2 Code Block:

MicroPython Code Block:

status = chain_tof_0.get_measure_status()

get_measure_complete_flag()

Get the measurement complete flag.

Returns:

Measurement complete flag. 0 means measurement not complete, 1 means measurement complete. Returns None if failed.

Return type:

int

UiFlow2 Code Block:

MicroPython Code Block:

flag = chain_tof_0.get_measure_complete_flag()