Value Display
Displays the latest datastream / virtual pin value formatted according to the datastream decimal place settings (DECIMALS) for numbers, and any units when defined.
Select or create a datastream of data type integer, double, enumerable, or string (does not accept location). 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 widget has no controls
The datastream value displayed is updated whenever the value stored on Blynk.Cloud changes.
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);
}
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.
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 towidgetProperty
: property you want to changepropertyValue
: 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.
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.
Blynk.setProperty(V1, "label", "Air temperature");
//#D3435C - Blynk RED
Blynk.setProperty(V1, "color", "#D3435C");
Widget will be greyed out on UI and users won't be able to tap on it.
Blynk.setProperty(V1, "isDisabled", true);
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);
get
https://{server_address}
/external/api/update/property?token={your 32 char token}&pin={your vPin}&{property}={value}
Updates the Datastream Property and all assigned Widgets
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()
}
Last modified 3mo ago