Dynamic pulse speed for visual feedback (flow meters, pump speed, charging rate, etc)

[serge402]

Component name

light

Link to component documentation on our website

https://esphome.io/components/light/

Describe the enhancement

Currently, the built-in pulse light effect has fixed transition_length and update_interval parameters that are set at compile time and cannot be changed dynamically during runtime:

effects:
  - pulse:
      name: "Slow Pulse"
      transition_length: 2s
      update_interval: 4s

I propose adding two new methods to the LightCall class (similar to existing methods like set_flash_length, set_brightness, set_transition_length):

• set_pulse_transition_length(uint32_t ms) - Dynamically set the fade in/out time

• set_pulse_update_interval(uint32_t ms) - Dynamically set the time for a complete pulse cycle

This would allow runtime control of pulse effects:

auto call = id(my_light).turn_on();
call.set_effect("Pulse");
call.set_pulse_transition_length(500);  // 0.5s fade
call.set_pulse_update_interval(1000);   // 1s complete cycle
call.perform();

Or in YAML automations:

on_value:
  then:
    - light.turn_on:
        id: my_light
        effect: "Pulse"
        pulse_transition_length: !lambda "return calculate_speed(x);"
        pulse_update_interval: !lambda "return calculate_speed(x) * 2;"

Use cases

1. Water/energy meter visualization - Pulse rate represents flow rate. The faster the pulse, the more water/energy flowing through the meter
2. Variable speed pump/fan indicators - LED pulse speed matches pump/fan RPM for visual feedback
3. Battery charge/discharge rate - Pulse speed indicates charging/discharging rate
4. Network traffic indicators - Pulse speed represents bandwidth usage
5. Temperature change rate - Faster pulses when temperature is changing rapidly

Currently, the only workaround is to either:

• Define multiple discrete pulse effects and switch between them (limited granularity, lots of code)
• Write complex custom lambda effects that reimplement pulsing from scratch (error-prone, resource-intensive)

Dynamic pulse control would make these use cases simple and elegant while keeping code lightweight.

Anything else?

Related API documentation: https://api-docs.esphome.io/classesphome_1_1light_1_1_light_call
The flash effect already has dynamic control via set_flash_length(), so this feature request follows the same pattern for the pulse effect.

[github-actions[bot]]

🏷️ I've automatically added the component: light label to help categorize this feature request.

[ssieb]

The LightCall can't have parameters for specific effects like that.
"Flash" is not an effect. It's a feature of the light component to make a single flash.