Energy Card

This feature is only available in ESP-DASH Pro

The Energy Card displays energy consumption values with a configurable unit.

Initializer

To create an energy card in ESP-DASH v5, use the dash::EnergyCard<T, Precision> class. The template parameters allow you to control the value type and decimal precision:

• T: Value type (e.g., float, int)
• Precision: Number of decimal places for floating point values (default: 2)

Example 1: Float value, default precision (2 decimals)

dash::EnergyCard<float> energy(dashboard, "Energy Consumption", "kWh");

Example 2: Float value, custom precision (3 decimals)

dash::EnergyCard<float, 3> energy3(dashboard, "Energy Consumption", "Joule");

Example 3: Integer value

dash::EnergyCard<int> energyInt(dashboard, "Energy Consumption", "Wh");

Methods

setValue(T value)

Set the energy value. The type of value must match the template type you chose for T (e.g., int, float).

energy.setValue(value); // value is of type T

• Signature: void setValue(T value)
• Parameters:
  • T value — The value to display (type matches template parameter T).
• Returns: void

value()

Get the current energy value. The return type matches your template type for T (e.g., int, float).

T v = energy.value();

• Signature: T value()
• Parameters: None
• Returns: T — The current value displayed by the card (type matches template parameter T).

Note:

• T can be one of: int or float depending on how you instantiate the card.

setUnit(const char* unit)

Set the unit or symbol for the energy card.

energy.setUnit("Joule");

• Signature: void setUnit(const char* unit)
• Parameters:
  • const char* unit — The unit or symbol to display.
• Returns: void

unit()

Get the unit or symbol for the energy card.

const char* unit = energy.unit();

• Signature: const char* unit()
• Parameters: None
• Returns: const char* — The current unit or symbol for the card.

Reference

Below is a reference code showing how to integrate this widget in a real project, including initialization and value updates usage.

// ...
 
// Create an energy card (float, 2 decimals by default)
dash::EnergyCard<float> energyCard(dashboard, "Energy Consumption", "kWh");
 
void setup() {
  // ...
  
  energyCard.setValue(123.4f);
  energyCard.setUnit("Joule");
}
 
void loop() {
  // ...
}