Device Element

The DeviceElement allows configuration of the behavior of the device and the features offered by the board class.

By specifying the configuration for the device element the general settings for the device can be controlled.

Element Configuration

The following properties are available for configuration of the element.

Basic settings

name - The device name is specifying the hostname that is used to register the device on the network. The device can be accessed by any browser on the same network using the URL http://<name>.

rebootTime (time) - Specifies the duration after the device is rebooted to fully clean up the memory.

logLevel - By specifying a logLevel for the device all elements will use this loglevel to output debug messages over the Serial interface and into the system log file. See also Device Logging.

logFile (boolean) - set to 1/true to enable storing lines from the system log to files. default: 0

onSysStart (actions) - These actions are dispatched when the elements are activated. Element that require a > valid local time are not started at this point.

onStart (actions) - These actions are dispatched when all elements are active.

sd - The mDNS based service discovery can be switched off by setting this property to false.

safemode (boolean) - This value can be set to 0/false to not use the safemode. See [safemode description](/dev/> safemode.md).

From the base element implementation the following properties are available for configuration:

title – Caption text for the element. Used by the element specific cards on the dash boards.

description – A line of text that gives a short description of the device used in the web UI.

room – The location of the device.

loglevel – This property holds the element specific log level. The default value is LOGGER_LEVEL_ERR == 1.

startup – This property can be used to start the element using a different initialization phase. Possible values are “sys”, “net”, “time”. See The Startup sequence.

WiFi-Manager and Startup settings

connectTime - The maximal time to search for a network connection. Default: “30s”.

Detailed description see WiFiManager.

I2C bus

Many connected sensors and displays are connected via the I2C bus. This bus must be initialized according to the onboard wiring by using the right SDA and SCL pins.

Because there is only 1 bus available in the Arduino boards the configuration is done centrally in the device.

I2C-SDA - the data line of the i2c bus.

I2C-SCL - the clock line of the i2c bus.

I2C-frequency - the clock speed on the i2c bus in Hz. Default is 100000 Hz. Can be reduced or changed up to 1000000 Hz.

The device Element is only defining what pins are used for the I2C bus but does no further initialization.

More hints on the I2C bus implementation see I2C

Web UI

homepage - When the device starts in normal mode this page will be shown when opening the device web UI using the url without specifying the page. This defaults to /index.htm

cache - This property can be used to replace the default http cache-control header for accessing the static files by a custom value. The default cache header is "no-cache" that is good while developing and configuring. But when have a stable configuration caching can be switched on using a value like "max-age=120" or "etag"

Deep Sleep mode

sleep - To start a deep sleep a sleep action needs to be send to the device element. A sleep=false action will disable any sleep mode until next restart. See also deep sleep mode.

nosleep - To block any deep sleep on the device until the next reboot a nosleep action can be send to the device element.

sleeptime (time) - The duration the device sleeps when a sleep action was sent.

Control the Device

The following action is implemented:

reset - This action wil immediately restart the device like using a reset button. No settings are changed or cleared.

Configuration Example

This example shows how to configure this element:

{
  "device": {
    "0": {
      "loglevel": 1,
      "name": "wmleaks",
      "title": "Water Leakage",
      "description": "Monitor water leaks at the washing machine",
      "room": "Cellar",
      "reboottime": "24h",
      "sleeptime": 600,
      "led": "D0",
      "button": "D3",
      "homepage": "ding-info.htm",
      "logfile": 1,
      "I2C-SDA" : "D4",
      "I2C-SCL" : "D5"
    }
  }
}