A Variable in Connected Sensors can store one or more data points. Variables are the most granular entity and can either be raw (sensor or manually sent data) or synthetic (computed from an expression using other variables).

Property	Type	Description
id	String	Id of Variable
label	String	Label of Variable
name	String	Name of Variable
description	String	Description of Variable
device	Object	The Device this Variable belongs to. Contains `id`, `label`, `name`, `url`, and `createdAt`.
tags	String Array	Tags of Variable
properties	Object	Properties of Variable. See Properties object below.
type	String	Variable type. Can be `raw` or `synthetic`. See Variable Types below.
unit	String	Unit of measurement for the Variable (e.g. `°C`, `m/s`, `%`). Can be `null`.
syntheticExpression	String	Mathematical expression used to compute the variable's value. Only applicable when `type` is `synthetic`. Empty string for `raw` variables.
createdAt	String	Date the Variable was created (ISO 8601 format).
lastValue	Object	The most recent data point sent to the Variable. See lastValue object below.
lastActivity	Number	Unix timestamp (ms) of the Variable's last recorded activity. Can be `null` if no data has been received.
url	String	URL of Variable
valuesUrl	String	URL to access the Variable's historical data points via the v1.6 API.

Variable

{
    "url": "https://api.connectedsensors.com/api/v2.0/variables/67253b189bcbc904dc48cd4c",
    "id": "67253b189bcbc904dc48cd4c",
    "label": "temp",
    "name": "Temperature",
    "description": "",
    "device": {
        "url": "https://api.connectedsensors.com/api/v2.0/devices/67253b189bcbc904dc48cd4d",
        "id": "67253b189bcbc904dc48cd4d",
        "label": "614385e15e4b40df8ecba871629a3c08",
        "name": "Itagüí",
        "createdAt": "2024-11-01T20:33:28.202904Z"
    },
    "tags": [],
    "properties": {
        "_icon": "thermometer-half",
        "_color": "#e9c46a",
        "_previous_variable_label": "temp"
    },
    "type": "raw",
    "unit": "°C",
    "syntheticExpression": "",
    "createdAt": "2024-11-01T20:33:28.319179Z",
    "lastValue": {
        "value": 17.84,
        "timestamp": 1771878262000,
        "context": {},
        "created_at": 1771878563537
    },
    "lastActivity": 1771878563539,
    "valuesUrl": "https://api.connectedsensors.com/api/v1.6/variables/67253b189bcbc904dc48cd4e/values"
}

Variable Types

The type field determines how a variable receives its value:

raw: The variable stores data points sent directly from a device or external source (e.g. sensors, API calls). The syntheticExpression field will be an empty string.
synthetic: The variable's value is automatically computed from a mathematical expression referencing other variables (indicated by {{variable_id}} placeholders in syntheticExpression). Synthetic variables do not receive raw data.

Synthetic variable example:

{
    "type": "synthetic",
    "syntheticExpression": "{{67253b189bcbc904dc48cd51}} * {{67253b189bcbc904dc48cd4f}}"
}

Properties object

The properties key object describes the following about a Variable:

Color.
Icon.
Timezone for data aggregation.

Property	Type	Description
`_icon`	String	Font Awesome v6.1.1 icon name assigned to the variable. For example, `"thermometer-half"`.
`_color`	String	Variable color in hexadecimal format. For example, `"#e9c46a"`.
`timezone`	String	Timezone used for data aggregation and display. Uses IANA timezone format. For example, `"America/Bogota"`.

Properties object example

{
    "properties": {
        "_icon": "thermometer-half",
        "_color": "#e9c46a",
        "timezone": "America/Bogota",
    }
}

lastValue object

The lastValue object contains the most recent data point recorded for the Variable. It will be an empty object {} if no data has been received yet.

Property	Type	Description
value	Number	The numeric value of the last data point.
timestamp	Number	Unix timestamp (ms) indicating when the value was measured or originated.
context	Object	Arbitrary key-value pairs sent alongside the value for additional metadata (e.g. cardinal direction, icon URLs). Can be an empty object `{}`.
created_at	Number	Unix timestamp (ms) indicating when the data point was stored in Connected Sensors.

lastValue object example

{
    "lastValue": {
        "value": 10.0,
        "timestamp": 1771878262000,
        "context": {
            "cardinal_direction": "N"
        },
        "created_at": 1771878563540
    }
}