Enhanced Gauge

Displays visually and numerically the latest datastream value, and optionally an arrow that indicates an increasing or decreasing trend, and optionally the value for the trend change. The trend change period is adjustable between 15 min and 1 day.

An indicator on a circle is positioned based on the latest datastream value and proportional to an arc of 270 degrees and the datastream min and max values. The last datastream value is also shown as a number in the center of the display. A filled radial arc of 270 degrees with a fading color from light to dark visually enhances the gauge.

Enhanced Gauge in different modes

Mode

The ‘Trend’ and ‘Trend change’ options change the mode between the following:

• ‘Trend’ disabled - the latest datastream value is displayed.

• ‘Trend’ enabled, ‘Trend change’ disabled -in addition to the display of the latest datastream value, an arrow point up (increasing trend) or down (decreasing trend) is shown based on the first and last values over the ‘TREND PERIOD’. The ‘TREND PERIOD’ is also displayed.

• ‘Trend’ enabled, ‘Trend change’ enabled - in addition to the display of the latest datastream value, an arrow point up (increasing trend) or down (decreasing trend) is shown, and to the right of the trend arrow a numerical value for the change in value over the ‘TREND PERIOD’. The ‘IGNORE DELTA FLUCTUATIONS’ setting will cause the trend calculation to ignore (filter) values less than this setting.

‘TREND PERIOD’ defines the period over which a trend will be evaluated. The options are: 15 min, 30 min, 1 h, 3h, 6h, 12h, 1d. No trend arrow or trend change numerical value will be displayed until at least one trend period has elapsed.

Datastream

Select or create a datastream of data type integer or double. Widget properties (label, color, etc.) are also changed via the datastream, but only for virtual, enumerable, and location pins, not digital and analog pins.

The “color” property changes the color of the radial gauge and the latest value shown in the center of the gauge.

Widget Controls

The widget has no controls.

How to process widget input on the device

The datastream value displayed is updated whenever the value stored on Blynk.Cloud changes.

Reading the widget value(s)

BLYNK_WRITE(V1) {
// Called when the datastream V1 value changes

// Assign incoming value from pin V1 to a variable
// according to the datastream data type
int pinValue = param.asInt(); 
// float pinValue = param.asFloat()
// double pinValue = param.asDouble();
// String pinValue = param.asStr()
// String pinValue = param.asString()
// String pinValue = param.getBuffer()  // raw data from param buffer
// int value = param.getLength()  // raw data from param buffer

if (pinValue == 1){
  // do something when the value is 1
} else if (pinValue == 0) {
  // do something when the value is 0
}

Serial.print("V1 value is: "); // print value to serial monitor
Serial.println(pinValue);
}

Changing the datastream value

You can update the assigned datastream value using the hardware or HTTP API.

Hardware:

Blynk.virtualWrite(vPin, 1);

HTTP API:

https://{server_address}/external/api/update/?token={your 32 char token}&V0=1

https://{server_address}/external/api/batch/update/?token={your 32 char token}&V0=1

Don't put Blynk.virtualWrite()into the void loop() as it can cause a flood of messages and your hardware will be disconnected. Send such updates only when necessary, use flags, or timers.

Sketch: Basic Sketch

Sketch: Set Property

Sketch: VirtualPinWrite

Sketch: VirtualPinRead

Change Widget Properties

You can change certain properties of the Widget from your hardware. For that, use this command:

Blynk.setProperty(vPin, "widgetProperty", "propertyValue"); 

Where:

• vPin is: virtual pin number the widget is assigned to

• widgetProperty: property you want to change

• propertyValue: value of the property you want to change

Don't put Blynk.setProperty()into the void loop() as it can cause a flood of messages and your hardware will be disconnected. Send such updates only when necessary, or use timers.

Properties you can change

You can change the properties label, color, isDisabled, isHidden of the widget from your hardware, or via an HTTP API. The URL must be encoded, so spaces in labels must be replaced with %20, and color hexadecimal values in the HTTP API URL must include the hash # character urlencoded as %23.

Change Label

Blynk.setProperty(V1, "label", "Air temperature");

Set Color

//#D3435C - Blynk RED 
Blynk.setProperty(V1, "color", "#D3435C");

Disable/Enable

Widget will be greyed out on UI and users won't be able to tap on it.

Blynk.setProperty(V1, "isDisabled", true);

Show/Hide

Widget will be hidden from dashboard. Design your UI so that it doesn't look weird when there is no widget.

Blynk.setProperty(V1, "isHidden", true);

Change widget properties via HTTPs API

Updates the Datastream Property and all assigned Widgets

GET https://{server_address}/external/api/update/property?token={your 32 char token}&pin={your vPin}&{property}={value}

The endpoint allows you to update the Datastream Property value via GET request. All widgets (both web and mobile) that are assigned to this datastream will inherit this property. The Datastream Property is persistent and will be stored forever until you change it with another value. In order to clear the property you need to clear the device data in device actions menu.

Example: https://blynk.cloud/external/api/update/property?token=GVki9IC70vb3IqvsV0YD3el4y0OpneL1&pin=V2&label=My%20Label

https://blynk.cloud/external/api/update/property?token=GVki9IC70vb3IqvsV0YD3el4y0OpneL1&pin=V1&color=%23D3435C

https://blynk.cloud/external/api/update/property?token=GVki9IC70vb3IqvsV0YD3el4y0OpneL1&pin=V1&isDisabled=true

Path Parameters

Name	Type	Description
{server address}*	string	Get from the bottom right of your Blynk console. More information.

Query Parameters

Name	Type	Description
token*	string	Device auth token from Device info
pin*	string	The datastream virtual pin (should start with "v")
{property}	string	The property of the widget you want to update: label, color, isDisabled, isHidden
label	string	the text used as widget label
color	string	button color hexadecimal, must include the hash # character urlencoded as %23
isDisabled	string	true or false
isHidden	string	true or false

200 Success

400 Could not find a device token

{"error":{"message":"Invalid token."}}

Sync to the latest known state

You can update your hardware to the latest datastream value from Blynk.Cloud after your hardware went offline, and then came online again. Use Blynk.syncVirtual() to update a single virtual pin, or Blynk.syncAll() to update all virtual pins. See State Syncing for more details.

BLYNK_CONNECTED() { 
  // Called when hardware is connected to Blynk.Cloud  

  // get the latest value for V1
  Blynk.syncVirtual(V1); 

  // Request Blynk server to re-send latest values for all pins
  Blynk.syncAll()
}