Homie Node Collection

Collection of nodes and examples for Homie. The nodes are designed as independent classes, so they can work standalone. For instance you can easily wire up a firmware for a Sonoff Relay by combining a ButtonNode with a RelayNode.

The software is based on Homie and is developed using PlatformIO It has recently been migrated to the Homie v3 Develop branch.

• Releases up to 1.0.x are using the Homie convention 2.0.1
• Releases from 1.1.x onwards are using the Homie convention 3.0.1

Sensor Nodes

All sensor nodes have a common $status subtopic wit the enum values: ok|error. $status is ok when a sensor could be detected and a valid measurement could be taken, error otherwise. All sensor nodes publish their data type on the $datatype subtopic. All sensor nodes publish their unit on the $unit subtopic. Most sensor nodes publish their format/value range on the $format subtopic. So if a sensor nodes publishes a temperature, you will see the following subtopics:

• homie/<device-id>/<node-name>/status
• homie/<device-id>/<node-name>/temperature
• homie/<device-id>/<node-name>/temperature/$datatype
• homie/<device-id>/<node-name>/temperature/$unit
• homie/<device-id>/<node-name>/temperature/$format

AdcNode.cpp

Homie Node using the internal ESP ADC to measure voltage.

It has three settings:

• adcCorrect: Correction factor for AD converter.
  Range = [0.5 - 1.5], Default = 1.

• battMax: Measured voltage that corresponds to 100% battery level.
  Must be greater than battMin. Range = [2.5V .. 4.0V]. Default = 3.3V.

• battMin: Measured voltage that corresponds to 0% battery level.
  Must be less than battMax. Range = [2.5V .. 4.0V]. Default = 2.6V.

Advertises the values as:

• homie/<device-id>/<node-name>/voltage
• homie/<device-id>/<node-name>/batterylevel

BME280Node

A node for Bosch BME280 I2C temperature/humidity/pressure sensors. Reports the three values back via MQTT.

It has one setting:

• temperatureOffset: The temperature offset in degrees.
  Range = [-10.0°C .. 10.0°C]. Default = 0°C.

Attention: This offset is just added to the temperature read from the sensor. The relative humidity is not recalculated.

Attention: Please be aware that the Homie framework doesn't know per-node settings. If you have more than one instance of a BME280Node, all instances will use the same temperatureOffset.

Advertises the values as:

• homie/<device-id>/<node-name>/temperature
• homie/<device-id>/<node-name>/humidity
• homie/<device-id>/<node-name>/pressure

DHT22Node

A node for DHT22 temperature/humidity sensors. Reports the two values back via MQTT.

Advertises the values as:

• homie/<device-id>/<node-name>/temperature
• homie/<device-id>/<node-name>/humidity

DS18B20Node

A Homie Node for Dallas 18B20 one wire temperature sensors. Reports the temperature back via MQTT.

Advertises the value as:

• homie/<device-id>/<node-name>/temperature

Actor Nodes

ButtonNode

A pushbutton that just detects a single button press. An optional callback can be triggered by the button press event. The button press is not reported back via MQTT. ToDo: detect multiple button presses and report them back.

ContactNode

A contact that reports its open state (true|false) via MQTT. An optional callback can be triggered by the state change event.

Advertises the state as:

• homie/<device-id>/<node-name>/open (true|false)

PulseNode

In some way similar to the contact node only that it reacts on pulses on the selected input pin. It reports its state (true|false) via MQTT. An optional callback can be triggered by the state change event. Imagine an optocoupler pulsing with 50Hz when a switch is closed or a button is pressed.

Advertises the state as:

• homie/<device-id>/<node-name>/active (true|false)

In order to use the PulseNode you need an interrupt procedure which is attached to the selected pin. e.G.:

void onOptoCouplerPulse()
{
  pulseNode.pulseDetected();
}

void setup()
{
  attachInterrupt(PIN_OPTOCOUPLER, onOptoCouplerPulse, FALLING);
}

RelayNode

A relay that can be set on (true|false) via MQTT message. An optional GPIO pin (e.g. to light up a LED) can be passed in the constructor. This pin will be set high/low synchronous to the relay. Additonally the relay can be turned on for a number of seconds by sending this number to the timeout subtopic.

• homie/<device-id>/<node-name>/on/set (true|false)
• homie/<device-id>/<node-name>/timeout/set (positive integer) - turns the relay on for the corresponding number of seconds.

Advertises the state as:

• homie/<device-id>/<node-name>/on (true|false)
• homie/<device-id>/<node-name>/timeout/ (positive integer) - the second (uptime of the relay node) when the relay will turn off again.