Humidity Card

The humidity card displays a numeric humidity reading, by default as a percentage, such as the output of a DHT22 or BME280 sensor.

ConstructorCopy Anchor Link

dash::HumidityCard<T, Precision> card(dashboard, name, unit);

Template parameters:

dash::HumidityCard humidity(dashboard, "Humidity");              // float, 2 decimals, %
dash::HumidityCard<float, 1> greenhouse(dashboard, "Greenhouse");
dash::HumidityCard<int> room(dashboard, "Room");

An overload without the dashboard argument creates the card without attaching it to a dashboard; attach it later with dashboard.add(card).

MethodsCopy Anchor Link

setValue()Copy Anchor Link

bool setValue(const T& value);

Sets the humidity value. Returns true if the value changed and an update is pending.

value()Copy Anchor Link

const T& value() const;

Returns the current value. Call it only when hasValue() returns true.

hasValue()Copy Anchor Link

bool hasValue() const;

Returns true if a value has been set.

removeValue()Copy Anchor Link

bool removeValue();

Clears the value. The dashboard then shows 0. Returns true if a value was removed.

setUnit()Copy Anchor Link

bool setUnit(const char* unit);

Sets the unit displayed next to the value. Returns true if the unit changed.

unit()Copy Anchor Link

const char* unit() const;

Returns the current unit.

ExampleCopy Anchor Link

#include <Arduino.h>
#include <WiFi.h>              // ESP32; use the networking headers for your board
#include <AsyncTCP.h>
#include <ESPAsyncWebServer.h>
#include <ESPDash.h>

AsyncWebServer server(80);
ESPDash dashboard(server);

dash::HumidityCard<float> humidity(dashboard, "Humidity", "%");

void setup() {
  // ... connect to Wi-Fi
  server.begin();
}

void loop() {
  float reading = 55.2f; // replace with a sensor reading
  humidity.setValue(reading);
  dashboard.sendUpdates();
  delay(3000);
}

NotesCopy Anchor Link

• The card stores the unit pointer and does not copy the string. Pass a string literal or a buffer that outlives the card.