Air Card

The air card displays an atmospheric pressure reading with a unit, such as the output of a BMP280 or BME680 sensor.

ConstructorCopy Anchor Link

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

Template parameters:

dash::AirCard pressure(dashboard, "Pressure");                 // float, 2 decimals, hPa
dash::AirCard<float, 3> pressureKpa(dashboard, "Pressure", "kPa");
dash::AirCard<int> pressurePa(dashboard, "Pressure", "Pa");

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(T value);

Sets the pressure 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, for example "hPa" or "kPa". 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 <ESPDashPro.h>

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

dash::AirCard<float> pressure(dashboard, "Pressure", "hPa");

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

void loop() {
  float reading = 1013.25f; // replace with a sensor reading
  pressure.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.
• Changing the unit does not convert the value; set a value in the new unit as well.