Lambda Magic ============ .. seo:: :description: Recipes for various interesting things you can do with Lambdas in ESPHome :image: language-cpp.svg Here are a couple recipes for various interesting things you can do with :ref:`Lambdas ` in ESPHome. These things don't need external or custom components, and show how powerful :ref:`Lambda ` usage can be. .. _lambda_magic_pages: Display pages alternative ------------------------- Some displays like :ref:`lcd-pcf8574` don't support pages natively, but you can easily implement them using Lambdas: .. code-block:: yaml display: - platform: lcd_pcf8574 dimensions: 20x4 address: 0x27 id: lcd lambda: |- switch (id(page)){ case 1: it.print(0, 1, "Page1"); break; case 2: it.print(0, 1, "Page2"); break; case 3: it.print(0, 1, "Page3"); break; } globals: - id: page type: int initial_value: "1" interval: - interval: 5s then: - lambda: |- id(page) = (id(page) + 1); if (id(page) > 3) { id(page) = 1; } .. _lambda_magic_udp_sender: Send UDP commands ----------------- There are various network devices which can be commanded with UDP packets containing command strings. You can send such UDP commands from ESPHome using a Lambda in a script. .. code-block:: yaml script: - id: send_udp parameters: msg: string host: string port: int then: - lambda: |- int sock = ::socket(AF_INET, SOCK_DGRAM, 0); struct sockaddr_in destination, source; destination.sin_family = AF_INET; destination.sin_port = htons(port); destination.sin_addr.s_addr = inet_addr(host.c_str()); // you can remove the next 4 lines if you don't want to set the source port for outgoing packets source.sin_family = AF_INET; source.sin_addr.s_addr = htonl(INADDR_ANY); source.sin_port = htons(64998); // the source port number bind(sock, (struct sockaddr*)&source, sizeof(source)); int n_bytes = ::sendto(sock, msg.c_str(), msg.length(), 0, reinterpret_cast(&destination), sizeof(destination)); ESP_LOGD("lambda", "Sent %s to %s:%d in %d bytes", msg.c_str(), host.c_str(), port, n_bytes); ::close(sock); button: - platform: template id: button_udp_sender name: "Send UDP Command" on_press: - script.execute: id: send_udp msg: "Hello World!" host: "192.168.1.10" port: 5000 Tested on both `arduino` and `esp-idf` platforms. .. _lambda_magic_uart_text_sensor: Custom UART Text Sensor ----------------------- Lots of devices communicate using the UART protocol. If you want to read lines from uart to a Text Sensor you can do so using this code example. With this you can use automations or lambda to set switch or sensor states. .. code-block:: cpp #include "esphome.h" class UartReadLineSensor : public Component, public UARTDevice, public TextSensor { public: UartReadLineSensor(UARTComponent *parent) : UARTDevice(parent) {} void setup() override { // nothing to do here } int readline(int readch, char *buffer, int len) { static int pos = 0; int rpos; if (readch > 0) { switch (readch) { case '\n': // Ignore new-lines break; case '\r': // Return on CR rpos = pos; pos = 0; // Reset position index ready for next time return rpos; default: if (pos < len-1) { buffer[pos++] = readch; buffer[pos] = 0; } } } // No end of line has been found, so return -1. return -1; } void loop() override { const int max_line_length = 80; static char buffer[max_line_length]; while (available()) { if(readline(read(), buffer, max_line_length) > 0) { publish_state(buffer); } } } }; (Store this file in your configuration directory, for example ``uart_read_line_sensor.h``) And in YAML: .. code-block:: yaml # Example configuration entry esphome: includes: - uart_read_line_sensor.h logger: level: VERBOSE #makes uart stream available in esphome logstream baud_rate: 0 #disable logging over uart uart: id: uart_bus tx_pin: D0 rx_pin: D1 baud_rate: 9600 text_sensor: - platform: custom lambda: |- auto my_custom_sensor = new UartReadLineSensor(id(uart_bus)); App.register_component(my_custom_sensor); return {my_custom_sensor}; text_sensors: id: "uart_readline" For more details see :doc:`/custom/uart` and :doc:`/components/uart`. .. _lambda_magic_uart_switch: Custom UART Switch ------------------ Here is an example switch using the uart text sensor above to set switch state. Here we use interval to request status from the device. The response will be stored in uart text sensor. Then the switch uses the text sensor state to publish its own state. .. code-block:: yaml switch: - platform: template name: "Switch" lambda: |- if (id(uart_readline).state == "*POW=ON#") { return true; } else if(id(uart_readline).state == "*POW=OFF#") { return false; } else { return {}; } turn_on_action: - uart.write: "\r*pow=on#\r" turn_off_action: - uart.write: "\r*pow=off#\r" interval: - interval: 10s then: - uart.write: "\r*pow=?#\r" .. _lambda_magic_rf_queues: Delaying Remote Transmissions ----------------------------- The solution below handles the problem of RF frames being sent out by :doc:`/components/rf_bridge` (or :doc:`/components/remote_transmitter`) too quickly one after another when operating radio controlled covers. The cover motors seem to need at least 600-700ms of silence between the individual code transmissions to be able to recognize them. This can be solved by building up a queue of raw RF codes and sending them out one after the other with (a configurable) delay between them. Delay is only added to the next commands coming from a list of covers which have to be operated at once from Home Assistant. This is transparent to the system, which will still look like they operate simultaneously. .. code-block:: yaml rf_bridge: number: - platform: template name: Delay commands icon: mdi:clock-fast entity_category: config optimistic: true restore_value: true initial_value: 750 unit_of_measurement: "ms" id: queue_delay min_value: 10 max_value: 1000 step: 50 mode: box globals: - id: rf_code_queue type: 'std::vector' script: - id: rf_transmitter_queue mode: single then: while: condition: lambda: 'return !id(rf_code_queue).empty();' then: - rf_bridge.send_raw: raw: !lambda |- std::string rf_code = id(rf_code_queue).front(); id(rf_code_queue).erase(id(rf_code_queue).begin()); return rf_code; - delay: !lambda 'return id(queue_delay).state;' cover: # have multiple covers - platform: time_based name: 'My Room 1' disabled_by_default: false device_class: shutter assumed_state: true has_built_in_endstop: true close_action: - lambda: id(rf_code_queue).push_back("AAB0XXXXX..the.closing.code..XXXXXXXXXX"); - script.execute: rf_transmitter_queue close_duration: 26s stop_action: - lambda: id(rf_code_queue).push_back("AAB0YXXXX..the.stopping.code..XXXXXXXXXX"); - script.execute: rf_transmitter_queue open_action: - lambda: id(rf_code_queue).push_back("AAB0ZXXXX..the.opening.code..XXXXXXXXXX"); - script.execute: rf_transmitter_queue open_duration: 27s .. _lambda_magic_1button_coover: One Button Cover Control ------------------------ The configuration below shows how with a single button you can control the motion of a motorized cover by cycling between: open->stop->close->stop->... In this example a :doc:`/components/cover/time_based` is used with the GPIO configuration of a Sonoff Dual R2. .. note:: Controlling the cover to quickly (sending new open/close commands within a minute of previous commands) might cause unexpected behaviour (eg: cover stopping halfway). This is because the delayed relay off feature is implemented using asynchronous automations. So every time an open/close command is sent a delayed relay off command is added and old ones are not removed. .. code-block:: yaml esp8266: board: esp01_1m binary_sensor: - platform: gpio pin: number: GPIO10 inverted: true id: button on_press: then: # logic for cycling through movements: open->stop->close->stop->... - lambda: | if (id(my_cover).current_operation == COVER_OPERATION_IDLE) { // Cover is idle, check current state and either open or close cover. if (id(my_cover).is_fully_closed()) { id(my_cover).open(); } else { id(my_cover).close(); } } else { // Cover is opening/closing. Stop it. id(my_cover).stop(); } switch: - platform: gpio pin: GPIO12 interlock: &interlock [open_cover, close_cover] id: open_cover - platform: gpio pin: GPIO5 interlock: *interlock id: close_cover cover: - platform: time_based name: "Cover" id: my_cover open_action: - switch.turn_on: open_cover open_duration: 60s close_action: - switch.turn_on: close_cover close_duration: 60s stop_action: - switch.turn_off: open_cover - switch.turn_off: close_cover Update numeric values from text input ------------------------------------- Sometimes it may be more confortable to use a :doc:`/components/text/template` to change some numeric values from the user interface. ESPHome has some nice `helper functions `__ among which theres's one to convert text to numbers. In the example below we have a text input and a template sensor which can be updated from the text input field. What the lambda does, is to parse and convert the text string to a number - which only succeedes if the entered string contains characters represesenting a float number (such as digits, ``-`` and ``.``). If the entered string contains any other characters, the lambda will return ``NaN``, which corresponds to ``unknown`` sensor state. .. code-block:: yaml text: - platform: template name: "Number type in" optimistic: true min_length: 0 max_length: 16 mode: text on_value: then: - sensor.template.publish: id: num_from_text state: !lambda |- auto n = parse_number(x); return n.has_value() ? n.value() : NAN; sensor: - platform: template id: num_from_text name: "Number from text" See Also -------- - :ref:`config-lambda` - :ref:`automation` - :ghedit:`Edit`