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Add some fixes in example code to make it more robust: - Prevent from buffer overflow - Add check on valid character
417 lines
12 KiB
ReStructuredText
417 lines
12 KiB
ReStructuredText
Lambda Magic
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============
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.. seo::
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:description: Recipes for various interesting things you can do with Lambdas in ESPHome
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:image: language-cpp.svg
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Here are a couple recipes for various interesting things you can do with :ref:`Lambdas <config-lambda>` in ESPHome.
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These things don't need external or custom components, and show how powerful :ref:`Lambda <config-lambda>` usage can be.
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.. _lambda_magic_pages:
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Display pages alternative
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-------------------------
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Some displays like :ref:`lcd-pcf8574` don't support pages natively, but you can easily implement them
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using Lambdas:
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.. code-block:: yaml
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display:
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- platform: lcd_pcf8574
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dimensions: 20x4
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address: 0x27
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id: lcd
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lambda: |-
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switch (id(page)){
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case 1:
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it.print(0, 1, "Page1");
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break;
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case 2:
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it.print(0, 1, "Page2");
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break;
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case 3:
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it.print(0, 1, "Page3");
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break;
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}
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globals:
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- id: page
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type: int
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initial_value: "1"
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interval:
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- interval: 5s
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then:
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- lambda: |-
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id(page) = (id(page) + 1);
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if (id(page) > 3) {
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id(page) = 1;
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}
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.. _lambda_magic_udp_sender:
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Send UDP commands
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-----------------
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There are various network devices which can be commanded with UDP packets containing command strings.
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You can send such UDP commands from ESPHome using a Lambda in a script.
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.. code-block:: yaml
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script:
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- id: send_udp
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parameters:
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msg: string
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host: string
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port: int
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then:
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- lambda: |-
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int sock = ::socket(AF_INET, SOCK_DGRAM, 0);
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struct sockaddr_in destination, source;
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destination.sin_family = AF_INET;
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destination.sin_port = htons(port);
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destination.sin_addr.s_addr = inet_addr(host.c_str());
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// you can remove the next 4 lines if you don't want to set the source port for outgoing packets
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source.sin_family = AF_INET;
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source.sin_addr.s_addr = htonl(INADDR_ANY);
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source.sin_port = htons(64998); // the source port number
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bind(sock, (struct sockaddr*)&source, sizeof(source));
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int n_bytes = ::sendto(sock, msg.c_str(), msg.length(), 0, reinterpret_cast<sockaddr*>(&destination), sizeof(destination));
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ESP_LOGD("lambda", "Sent %s to %s:%d in %d bytes", msg.c_str(), host.c_str(), port, n_bytes);
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::close(sock);
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button:
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- platform: template
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id: button_udp_sender
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name: "Send UDP Command"
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on_press:
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- script.execute:
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id: send_udp
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msg: "Hello World!"
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host: "192.168.1.10"
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port: 5000
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Tested on both `arduino` and `esp-idf` platforms.
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.. _lambda_magic_uart_text_sensor:
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Custom UART Text Sensor
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-----------------------
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Lots of devices communicate using the UART protocol. If you want to read
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lines from uart to a Text Sensor you can do so using this code example.
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With this you can use automations or lambda to set switch or sensor states.
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.. code-block:: cpp
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#include "esphome.h"
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class UartReadLineSensor : public Component, public UARTDevice, public TextSensor {
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public:
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UartReadLineSensor(UARTComponent *parent) : UARTDevice(parent) {}
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void setup() override {
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// nothing to do here
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}
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int readline(int readch, char *buffer, int len)
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{
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static int pos = 0;
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int rpos;
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if (readch > 0) {
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switch (readch) {
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case '\n':
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case '\r': // Return on CR or newline
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buffer[pos] = 0; // Just to be sure, set last character 0
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rpos = pos;
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pos = 0; // Reset position index ready for next time
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return rpos;
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default:
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if ((pos < len-1) && ( readch < 127 )) { // Filter on <127 to make sure it is a character
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buffer[pos++] = readch;
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buffer[pos] = 0;
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}
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else
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{
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buffer[pos] = 0; // Just to be sure, set last character 0
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rpos = pos;
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pos = 0; // Reset position index ready for next time
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return rpos;
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}
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}
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}
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// No end of line has been found, so return -1.
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return -1;
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}
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void loop() override {
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const int max_line_length = 80;
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static char buffer[max_line_length];
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while (available()) {
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if(readline(read(), buffer, max_line_length) > 0) {
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publish_state(buffer);
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}
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}
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}
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};
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(Store this file in your configuration directory, for example ``uart_read_line_sensor.h``)
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And in YAML:
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.. code-block:: yaml
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# Example configuration entry
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esphome:
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includes:
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- uart_read_line_sensor.h
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logger:
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level: VERBOSE #makes uart stream available in esphome logstream
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baud_rate: 0 #disable logging over uart
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uart:
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id: uart_bus
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tx_pin: GPIOXX
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rx_pin: GPIOXX
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baud_rate: 9600
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text_sensor:
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- platform: custom
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lambda: |-
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auto my_custom_sensor = new UartReadLineSensor(id(uart_bus));
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App.register_component(my_custom_sensor);
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return {my_custom_sensor};
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text_sensors:
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id: "uart_readline"
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For more details see :doc:`/custom/uart` and :doc:`/components/uart`.
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.. _lambda_magic_uart_switch:
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Custom UART Switch
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------------------
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Here is an example switch using the uart text sensor above to set switch state.
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Here we use interval to request status from the device. The response will be stored in uart text sensor.
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Then the switch uses the text sensor state to publish its own state.
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.. code-block:: yaml
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switch:
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- platform: template
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name: "Switch"
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lambda: |-
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if (id(uart_readline).state == "*POW=ON#") {
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return true;
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} else if(id(uart_readline).state == "*POW=OFF#") {
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return false;
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} else {
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return {};
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}
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turn_on_action:
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- uart.write: "\r*pow=on#\r"
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turn_off_action:
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- uart.write: "\r*pow=off#\r"
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interval:
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- interval: 10s
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then:
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- uart.write: "\r*pow=?#\r"
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.. _lambda_magic_rf_queues:
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Delaying Remote Transmissions
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-----------------------------
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The solution below handles the problem of RF frames being sent out by :doc:`/components/rf_bridge` (or
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:doc:`/components/remote_transmitter`) too quickly one after another when operating radio controlled
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covers. The cover motors seem to need at least 600-700ms of silence between the individual code transmissions
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to be able to recognize them.
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This can be solved by building up a queue of raw RF codes and sending them out one after the other with
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(a configurable) delay between them. Delay is only added to the next commands coming from a list of
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covers which have to be operated at once from Home Assistant. This is transparent to the system, which
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will still look like they operate simultaneously.
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.. code-block:: yaml
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rf_bridge:
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number:
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- platform: template
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name: Delay commands
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icon: mdi:clock-fast
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entity_category: config
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optimistic: true
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restore_value: true
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initial_value: 750
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unit_of_measurement: "ms"
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id: queue_delay
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min_value: 10
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max_value: 1000
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step: 50
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mode: box
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globals:
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- id: rf_code_queue
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type: 'std::vector<std::string>'
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script:
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- id: rf_transmitter_queue
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mode: single
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then:
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while:
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condition:
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lambda: 'return !id(rf_code_queue).empty();'
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then:
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- rf_bridge.send_raw:
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raw: !lambda |-
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std::string rf_code = id(rf_code_queue).front();
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id(rf_code_queue).erase(id(rf_code_queue).begin());
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return rf_code;
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- delay: !lambda 'return id(queue_delay).state;'
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cover:
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# have multiple covers
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- platform: time_based
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name: 'My Room 1'
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disabled_by_default: false
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device_class: shutter
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assumed_state: true
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has_built_in_endstop: true
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close_action:
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- lambda: id(rf_code_queue).push_back("AAB0XXXXX..the.closing.code..XXXXXXXXXX");
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- script.execute: rf_transmitter_queue
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close_duration: 26s
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stop_action:
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- lambda: id(rf_code_queue).push_back("AAB0YXXXX..the.stopping.code..XXXXXXXXXX");
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- script.execute: rf_transmitter_queue
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open_action:
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- lambda: id(rf_code_queue).push_back("AAB0ZXXXX..the.opening.code..XXXXXXXXXX");
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- script.execute: rf_transmitter_queue
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open_duration: 27s
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.. _lambda_magic_1button_coover:
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One Button Cover Control
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------------------------
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The configuration below shows how with a single button you can control the motion of a motorized cover
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by cycling between: open->stop->close->stop->...
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In this example a :doc:`/components/cover/time_based` is used with the GPIO configuration of a Sonoff Dual R2.
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.. note::
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Controlling the cover to quickly (sending new open/close commands within a minute of previous commands)
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might cause unexpected behaviour (eg: cover stopping halfway). This is because the delayed relay off
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feature is implemented using asynchronous automations. So every time an open/close command is sent a
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delayed relay off command is added and old ones are not removed.
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.. code-block:: yaml
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esp8266:
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board: esp01_1m
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binary_sensor:
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- platform: gpio
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pin:
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number: GPIO10
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inverted: true
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id: button
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on_press:
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then:
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# logic for cycling through movements: open->stop->close->stop->...
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- lambda: |
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if (id(my_cover).current_operation == COVER_OPERATION_IDLE) {
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// Cover is idle, check current state and either open or close cover.
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if (id(my_cover).is_fully_closed()) {
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id(my_cover).open();
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} else {
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id(my_cover).close();
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}
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} else {
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// Cover is opening/closing. Stop it.
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id(my_cover).stop();
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}
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switch:
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- platform: gpio
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pin: GPIO12
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interlock: &interlock [open_cover, close_cover]
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id: open_cover
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- platform: gpio
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pin: GPIO5
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interlock: *interlock
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id: close_cover
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cover:
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- platform: time_based
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name: "Cover"
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id: my_cover
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open_action:
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- switch.turn_on: open_cover
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open_duration: 60s
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close_action:
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- switch.turn_on: close_cover
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close_duration: 60s
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stop_action:
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- switch.turn_off: open_cover
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- switch.turn_off: close_cover
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Update numeric values from text input
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-------------------------------------
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Sometimes it may be more confortable to use a :doc:`/components/text/template` to change some numeric values from the user interface.
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ESPHome has some nice `helper functions <https://github.com/esphome/esphome/blob/dev/esphome/core/helpers.h>`__ among which
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theres's one to convert text to numbers.
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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
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does, is to parse and convert the text string to a number - which only succeedes if the entered string contains characters
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represesenting a float number (such as digits, ``-`` and ``.``). If the entered string contains any other characters, the lambda
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will return ``NaN``, which corresponds to ``unknown`` sensor state.
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.. code-block:: yaml
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text:
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- platform: template
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name: "Number type in"
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optimistic: true
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min_length: 0
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max_length: 16
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mode: text
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on_value:
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then:
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- sensor.template.publish:
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id: num_from_text
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state: !lambda |-
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auto n = parse_number<float>(x);
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return n.has_value() ? n.value() : NAN;
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sensor:
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- platform: template
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id: num_from_text
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name: "Number from text"
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See Also
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--------
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- :ref:`config-lambda`
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- :ref:`automation`
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- :ghedit:`Edit`
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