Lambda Magic¶
Here are a couple recipes for various interesting things you can do with Lambdas in ESPHome. These don’t require external components and demonstrate how powerful Lambdas can be.
Display pages alternative¶
Some displays like lcd_pcf8574 Component don’t support pages natively, but you can easily implement them using Lambdas:
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;
}
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.
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<sockaddr*>(&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.
Delaying Remote Transmissions¶
The solution below handles the problem of RF frames being sent out by RF Bridge Component (or 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.
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<std::string>'
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
Update numeric values from text input¶
Sometimes it may be more confortable to use a Template Text 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.
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<float>(x);
return n.has_value() ? n.value() : NAN;
sensor:
- platform: template
id: num_from_text
name: "Number from text"
Factory reset after 5 quick reboots¶
One may want to restore factory settings (like Wi-Fi credentials set at runtime, or clear restore states) without having to disassemble or dismount the devices from their deployed location, whilst there’s no network access either. The example below shows how to achieve that using lambdas in a script by triggering the factory reset switch after the system rebooted 5 times with 10-second timeframes.
# Example config.yaml
esphome:
name: "esphome_ld2410"
on_boot:
priority: 600.0
then:
- script.execute: fast_boot_factory_reset_script
esp32:
board: esp32-c3-devkitm-1
substitutions:
factory_reset_boot_count_trigger: 5
globals:
- id: fast_boot
type: int
restore_value: yes
initial_value: '0'
script:
- id: fast_boot_factory_reset_script
then:
- if:
condition:
lambda: return ( id(fast_boot) >= ${factory_reset_boot_count_trigger});
then:
- lambda: |-
ESP_LOGD("Fast Boot Factory Reset", "Performing factotry reset");
id(fast_boot) = 0;
fast_boot->loop();
global_preferences->sync();
- button.press: factory_reset_button
- lambda: |-
if(id(fast_boot) > 0)
ESP_LOGD("Fast Boot Factory Reset", "Quick reboot %d/%d, do it %d more times to factory reset", id(fast_boot), ${factory_reset_boot_count_trigger}, ${factory_reset_boot_count_trigger} - id(fast_boot));
id(fast_boot) += 1;
fast_boot->loop();
global_preferences->sync();
- delay: 10s
- lambda: |-
id(fast_boot) = 0;
fast_boot->loop();
global_preferences->sync();
wifi:
id: wifi_component
ap:
ap_timeout: 0s
reboot_timeout: 0s
captive_portal:
button:
- platform: factory_reset
id: factory_reset_button
name: "ESPHome: Factory reset"