I bought some ESP32 C3 Super Mini boards that have an RGB LED, and information for the onboard LEDs wasn't as easy to find as for the standard ESP32 dev board, so I wanted to consolidate my notes here.
Standard ESP32 dev boards often have a single LED driven by GPIO2. As a strapping pin it's pulled high by default, so the led will turn on when the board gets power and will stay on if the pin is not set low. With ESPHome, it's easy to setup the Status LED component which will turn off the LED after boot, and blink it if there is a warning or error.
status_led:
pin:
number: 2
ignore_strapping_warning: True
For the C3 boards I purchased there is a basic LED and an addressable RGB LED, both connected to pin 8. During boot the RGB LED will flash then turn off, while the basic LED will remain on. Setting GPIO8 high or low will control the basic LED, so the status LED component can be used by configuring it to the correct pin, but the RGB LED will remain off.
The RGB light is a WS2812, and can be controlled with the ESP32 RMT LED Strip component which works with both the ESP-IDF and Arduino frameworks. The Arduino framework also has NeoPixelBus Light and FastLED components as options.
light:
- platform: esp32_rmt_led_strip
id: board_rgb_led
pin:
number: 8
ignore_strapping_warning: True
num_leds: 1
chipset: WS2812
rgb_order: GRB
It is not possible to control both LEDs by just enabling both light components and setting allow_other_uses for the pin.
The Status LED component can only be configured to a pin, so can't use the RGB LED. The Status LED Light component which enables controlling the LED when it's not being used to show a warning or error status can be configured to control a binary output component instead of a pin - a Template Binary Output component could use its write_action trigger to control the RGB light during a warning/error state [1].
Another option instead of using the status component is using on_loop with a custom lambda to check for an error state and adjust the RGB LED.
This is the definition I put together to slow blink yellow on warning, and fast blink red on error:
substitutions:
status_pin: GPIO8
esphome:
on_loop:
then:
lambda: |-
static uint32_t last_state = 0;
auto state = App.get_app_state();
if (state != last_state) {
if (state & STATUS_LED_ERROR) {
auto call = id(board_led).turn_on();
call.set_brightness(.2);
call.set_rgb(1, 0.01, 0.01);
call.set_effect("fast-pulse");
call.perform();
} else if (state & STATUS_LED_WARNING) {
auto call = id(board_led).turn_on();
call.set_brightness(.2);
call.set_rgb(1, 1, 0.01);
call.set_effect("slow-pulse");
call.perform();
} else {
auto call = id(board_led).turn_off();
call.perform();
}
last_state = state;
}
light:
- platform: esp32_rmt_led_strip
id: board_led
pin:
number: ${status_pin}
ignore_strapping_warning: True
num_leds: 1
chipset: WS2812
rgb_order: GRB
effects:
- pulse:
name: "fast-pulse"
update_interval: 0.3s
transition_length: 0.3s
min_brightness: 15% # Light turns off below 11%
max_brightness: 50%
- pulse:
name: "slow-pulse"
update_interval: 1s
transition_length: 1s
min_brightness: 15%
max_brightness: 50%
I then include it for my projects running on C3 boards:
packages:
- !include common/c3-rgb-status.yaml
There's an open PR to implement triggers for status changes, which would replace the need for on_loop
Top comments (2)
This is an interesting and promising area, especially as robots become more accessible to mainstream users
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