Check new version: https://github.com/lkankowski/arduino-multi-relay2.

This version is not maintained anymore.

About

Arduino program to handle relays and control them using switches. Single pair of relay and switch are configured in single line. Buttons has debouncing and support for mono- and bi-stable switches. There is support for multiple switches for single relay and virtual switches for devices only accessible from Home App.

I left configuration variable myRelayButtons[] which is used at my house, so before use you HAVE TO change it.

Configuration

First time only

Copy file "config.h.sample" into "config.h". On any future code update, you won't have to copy configuration to a newer version.

Main config file "config.h"

RelayButton myRelayButtons[] = {
    {sensor ID, relay pin, button pin, relay options, button type, relay description}
};

Params description:

• sensor ID - sensor ID reported on MySensor Gateway (ie. Domoticz/Home Assistant), must be unique (can be -1 when it is not reported MySensor Gateway)
• relay pin - pin connected to the relay. Expander is supported (see details inseparate section)
• button pin - pin connected to the button. There can be multiple buttons to the same relay. "<0" for virtual buttons (only available in MySensor Gateway, ie. Domoticz/Home Assistant). There is no support for Expander because of de-bouncing.
• relay options - combined with '|' operator:
  • RELAY_TRIGGER_LOW or RELAY_TRIGGER_HIGH - trigger level, required
  • RELAY_STARTUP_ON or RELAY_STARTUP_OFF - startup state, optional
  • RELAY_IMPULSE - optional, relay is turned on only for short period of time (defined in constant RELAY_IMPULSE_INTERVAL, 250ms by default), ignored for DING_DONG and REED_SWITCH buttons
• button type:
  • MONO_STABLE - GND connected to the button pin
  • BI_STABLE - state change from LOW to HIGH and HIGH to LOW, used with mechanical and touch buttons
  • DING_DONG - doorbell button, relay is triggered only when button is pushed (experimental, not tested)
  • REED_SWITCH - door/window sensor, oposite to DING_DONG - state LOW when door/window is closed, HIGH when opened
• relay description - reported on MySensor Gateway, can help identify device on initial configuration in Home Automation App (ie. Domoticz/Home Assistant), can be empty ("")

In my case, I have a documentation of whole electricity of my house in Google Calc, and I have a formula to generate this configuration.

Mono-stable buttons

For mono-stable buttons you can define in "config.h" if relay is triggered when you push button:

const uint8_t MONO_STABLE_TRIGGER = LOW;

or when button is released:

const uint8_t MONO_STABLE_TRIGGER = HIGH;

Debugging

In a sketch file:

#define MY_DEBUG

Just comment this on production.

Sample configurations

Simple mono-stable switch and relay pair

Relay is connected to pin 12, button is connected to pin 11, relay is triggered to ON using LOW state, button is mono-stable

RelayButton myRelayButtons[] = {
    {1, 12, 11, RELAY_TRIGGER_LOW, MONO_STABLE, ""}
};

Simple bi-stable switch and relay pair

Relay is connected to pin 12, button is connected to pin 11, relay is triggered to ON using HIGH state, button is bi-stable

RelayButton myRelayButtons[] = {
    {1, 12, 11, RELAY_TRIGGER_HIGH, BI_STABLE, ""}
};

Simple two mono-stable switch for one relay

Relay is connected to pin 12, buttons are connected to pins 11 and 10, relay is triggered to ON using HIGH state, buttons are mono-stable

RelayButton myRelayButtons[] = {
    {1, 12, 11, RELAY_TRIGGER_HIGH, MONO_STABLE, ""}
    {2, 12, 10, RELAY_TRIGGER_HIGH, MONO_STABLE, ""}
};

Mono-stable button with relay that starts turned on

RelayButton myRelayButtons[] = {
    {1, 12, 11, RELAY_TRIGGER_HIGH | RELAY_STARTUP_ON, MONO_STABLE, ""}
};

Two similar doorbell configuration

RelayButton myRelayButtons[] = {
    {1, 12, 11, RELAY_TRIGGER_HIGH | RELAY_IMPULSE, MONO_STABLE, ""}
};

is equivalent to:

RelayButton myRelayButtons[] = {
    {1, 12, 11, RELAY_TRIGGER_HIGH, DING_DONG, ""}
};

Difference is that the first example will do only 250ms impulse (turn on - wait ~250ms - turn off), and the second will turn on the relay as long, as button is pushed.

Door or window sensor

RelayButton myRelayButtons[] = {
    {1, 12, 11, RELAY_TRIGGER_HIGH, REED_SWITCH, ""}
};

Expander

Only one expander library at a time is supported.

PCF8574

To use expander PCF8574 you have to install library (https://github.com/skywodd/pcf8574_arduino_library) Basic information about expander and library you can find here - https://youtu.be/JNmVREucfyc (PL, library in description)

And uncomment expander library:

#include "PCF8574.h"

MCP23017

https://github.com/adafruit/Adafruit-MCP23017-Arduino-Library

Uncomment expander library:

#include "Adafruit_MCP23017.h"

Configuration

Configure all expanders id: I.e. only one PCF8574 expander with id = 0x20:

uint8_t expanderAddresses[] = {0x20};

I.e. only one MCP23017 expander with id = 0:

uint8_t expanderAddresses[] = {0};

From now you can use expander pins in configuration myRelayButtons[]. To recognize expander pin, numbers start from 0x0100 and have special meaning:

• first byte - expander number (starts from 1)
• second byte - pin number In example - "0x0100" means pin 0 on first expander

To simplify using expanders, there is "E(a,b)" macro:

• a - expander number (starts from 0)
• b - pin on expander [0-f]

E(0,0) - first pin on first expander