To make it easier to work with certain 1-Wire devices we implemented module called bc_onewire_relay which allows you to control relay modules connected via 1-Wire bus, for example the Relay module developed by Denkovi.


For this tutorial you need:

  • Core module
  • Sensor module
  • relay module controlled over 1-Wire bus


Documentation for this SDK module can be found here.

There is very simple workflow for controlling the relay:

  • you have to instantiate a variable representing the relay bc_onewire_relay_t relay;
  • relay connection has to be initiated in application_init() function by calling bc_onewire_relay_init(&relay, BC_GPIO_P4, 0x00);

    • the second parameter represents ports A and B on the Sensor module. Use _P4 for A and _P5 for B.
    • the third parameter represents number of connected device represented as uint64_t value
  • now you only have to use the bc_onewire_relay_set_state() function to set desired state of every relay


In this example we allow the relays to be controlled with button integrated to Core module. On every press of the button one more relay will be activated. When all relays are active, the next push of button will switch off all of them and the cycle repeats.

#include <application.h>
#include <bc_onewire_relay.h>
#include <bc_button.h>

bc_onewire_relay_t relay;
bc_button_t button;

bc_onewire_relay_channel_t relays[] = {

int activated = 0;

void button_event_handler(bc_button_t *self, bc_button_event_t event, void *event_param)
    (void) self;
    (void) event_param;

    if (event == BC_BUTTON_EVENT_PRESS)
        if (activated == 8) {
            for (int i = 0; i < 8; ++i) {
                bc_onewire_relay_set_state(&relay, relays[i], false);

            activated = 0;
        } else {
            bc_onewire_relay_set_state(&relay, relays[activated], true);

void application_init(void)
    bc_onewire_relay_init(&relay, BC_GPIO_P4, 0x00);

    bc_button_init(&button, BC_GPIO_BUTTON, BC_GPIO_PULL_DOWN, 0);
    bc_button_set_event_handler(&button, button_event_handler, NULL);

Example 2

You can find similar example on GitHub

Chapters in this document:
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