IO Module (ID 6)


The IoModule with ModuleId 6 can be used for basic driving and configuring of GPIOs. E.g. toggling a LED, a motor or reading values from a basic sensor.


The IoModule only supports toggling of LEDs and different pins at the moment. It will be extended to include support for basic sensors that can be read by e.g. analog/digital conversion.

The functionality was implemented using two different concepts:

For more information on the Register based access, see Register Access.

LED and Demo Functionality

The following commands are either used to control the LED state or for demo purpose. To access input or output pins in a more generic way, see the register access chapter.

Change LED Mode

Changes the LED mode to one of the states. It is possible to turn leds on or off, but also eg. signal number of mesh connections. This is mostly used for showing off the mesh functionality and testing. Setting the LED mode is typically done in the featureset.

Mode Blink pattern


all LEDs are on


all LEDs are forced off (will periodically make sure they are off)


LEDs are not controlled by the IoModule and another module can control their states


no mesh connections ⇒ red LED blinking three times
connected to mesh ⇒ green LED blinking for connection count
in case networkId equals 1 ⇒ red LED constantly on (legacy functionality)

//Set led mode
action [nodeId] io led [mode = on / off / connections / custom]

//Switch leds on for all nodes
action 0 io led on

Set Pins

Sets a pin to either high or low output. This is mostly used for demo or testing purpose. Any pin number can be given.

Be aware that the pin will be configured as an output pin and the LED mode will be set to CUSTOM.
//Configure pins low or high
action [nodeId] io pinset [pinNumber] [mode] ...

//Configure Pins 21 and 22
action 0 io pinset 21 high 22 low

Read Pins

Reads the digital level of one or up to 5 pins (0 = low and 1 = high). This is mostly a demo or testing command.

This changes the pin’s GPIO configuration to output after temporarily setting it to input.
//Pass the pin numbers to read
action [nodeId] io pinread [pinNumber] {pinNumber} ...

//Read pin 21
action 0 io pinread 21

//Read pins 2, 1 and 19
action 0 io pinread 2 1 19

Example response:

    "nodeId": 2,
    "type": "pin_level_result",
    "module": 6,
    "pins": [
        {"pin_number":  2, "pin_level": 1},
        {"pin_number":  1, "pin_level": 1},
        {"pin_number": 19, "pin_level": 0}

Start identification

Starts the identification procedure which will blink all LEDs with a 200ms period for a total of 30 seconds. Can also be handled by other modules to start custom identification. This mode overrules the curent led mode.

//Trigger identification
action [nodeId] io identify [mode = on / off]

//Trigger identification
action 0 io identify on

Register Based Generic GPIO Functionality

We offer a generic register based access to input and output pins that is well suited for reading out sensors or controlling actuators connected on the PCB. Combined with AutoSense and AutoAct, this allows for a number of sophisticated automation tasks as well.

Register Mapping

Component Register Name DataType (Length) Min …​ Max (Default) R/W Description

Information Registers







Provides the number of digital output pins configured through numDigitalOutPins







Provides the number of digital input pins configured through numDigitalInPins







Provides the number of digital input toggle pairs configured through numDigitalInTogglePairSettings

Control Registers


20000 …​ 20099



0 …​ 1 (0)


A range of registers that controls digital output pins suitable for driving simple actuators. These are configurable through the Boardsettings. (0=Inactive, 1=Active)

Data Registers


30000 …​ 30099



0 …​ 1


A range of registers that provides digital input pins suitable for digital sensors or toggle buttons. (0=Inactive, 1=Active)


30100 …​ 30199



0 …​ 1


Provides the current state of the toggle pair. A toggle pair is an easy way of implementing a switch based on two pushbuttons. The pushbuttons need to be configured with interrupts and are then able to store the timestamp of when they were pressed the last time. A toggle pair will then compare the two timestamps to evaluate the current state of the toggle as 0 or 1.


31000 …​ 31399





Provides a timestamp in deciseconds (since device boot) that is updated once the input pin is active. For a button, this is the timestamp when it was pressed the last time. The timestamp will not be updated periodically if the input is active for a long time.


30400 …​ 30799





Provides a timestamp in deciseconds (since device boot) that is updated only when the input was active for more than 500ms. The timestamp will be updated periodically as long as the input is active. This is useful to e.g. detect a long press for a pushbutton.

Potential Use-Cases

  • Manually query the state of an attached button or digital sensor: Use a component_act message with read for DIO_INPUT_STATE_1 as seen in the examples below.

  • Manually check the state of a digital output: Use component_act with read for DIO_OUTPUT_STATE_1.

  • Toggle an LED based on the state of a pushbutton: Use AutoSense to report DIO_INPUT_STATE_1 on change, then use AutoAct to push this value into DIO_OUTPUT_STATE_1.

  • Configure two buttons to toggle an LED: Configure AutoSense to report DIO_TOGGLE_PAIR_1 on change and use AutoAct to push this value into DIO_OUTPUT_STATE_1.

  • Report an event each time a button was pressed: Use AutoSense to watch the DIO_INPUT_LAST_ACTIVE_TIME_1 on change.

  • Report dimming events once a pushbutton was pressed for more than 500ms: Use AutoSense to report the DIO_INPUT_LAST_HOLD_TIME_1 on change.

//Set the first digital output to 1 and the second digital output to 0
component_act this 6 writeack 0 20000 01:00

//Read the state of the first two digital inputs
component_act this 6 read 0 30000 02

//Read the state of the first digital output
component_act this 6 read 0 20000 01

//Check the timestamp for when the first input was active
component_act this 6 read 0 31000 04

Implementation Details

The SET_LED(_RESPONSE) and SET_IDENTIFICATION(_RESPONSE) messages are also transmitted over via MeshAccessConnections which are established with the FmKeyId::ORGANIZATION. This is required for devices which are not part of the mesh network, but instead part of the organization.