Display values from Home Assistant on a display (1602A) using ESP32

I wanted to create a simple way to quickly display the current power consumption of the household and the power generation of a PV system.
Since I still had an ESP32 and a 1602A display, I created the display using the following code.

After the current power consumption, a simple bar is created using the # symbol, which roughly visualises the consumption.

YAML

esphome:
  name: esp2
  friendly_name: esp2

esp32:
  board: esp32dev
  framework:
    type: arduino

# Enable logging
logger:

# Enable Home Assistant API
api:
  encryption:
    key: "xxxxxxxxxxxxx"

ota:
  - platform: esphome
    password: "xxxxxxxxxxxxx"

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Esp2 Fallback Hotspot"
    password: "xxxxxxxxxxxxx"

captive_portal:

# Home Assistant Sensors
sensor:
  - platform: homeassistant
    entity_id: sensor.sensor_shelly_pro3em_strom_total_active_power
    id: stromverbrauch
    filters:
      - lambda: |-
          const float MAX_VERBRAUCH = 3000.0; /* Limit for max 400W display */
          return fmax(0.0, fmin(x, MAX_VERBRAUCH));

  - platform: homeassistant
    entity_id: sensor.bkw_total_watt
    id: pv_erzeugung
    filters:
      - lambda: |-
          const float MAX_ERZEUGUNG = 700.0; /* Limit for max 700W display */
          return fmax(0.0, fmin(x, MAX_ERZEUGUNG));

# LCD Display with graphical representation
display:
  - platform: lcd_gpio
    dimensions: 16x2
    data_pins: [4, 16, 17, 5]
    enable_pin: 18
    rs_pin: 19
    update_interval: 15s
    lambda: |-
      const int MAX_LENGTH = 16; // Maximum bar length (LCD width)
      const float MAX_VERBRAUCH = 3000.0; // Max value for 100% bar length (Consumption)
      const float MAX_ERZEUGUNG = 700.0;
      
      // Calculate bar lengths
      int verbrauch_bar = (id(stromverbrauch).state / MAX_VERBRAUCH) * (MAX_LENGTH - 7);
      int pv_bar = (id(pv_erzeugung).state / MAX_ERZEUGUNG) * (MAX_LENGTH - 7);

      // Ensure values do not exceed limits
      verbrauch_bar = fmax(0, fmin(verbrauch_bar, MAX_LENGTH - 7));
      pv_bar = fmax(0, fmin(pv_bar, MAX_LENGTH - 7));

      // Display consumption with watt value
      it.printf(0, 0, "V: %.0fW ", id(stromverbrauch).state);
      for (int i = 0; i < verbrauch_bar; i++) {
        it.print(i + 9, 0, "#"); // ASCII bar for consumption
      }

      // Display PV generation with watt value
      it.printf(0, 1, "E: %.0fW ", id(pv_erzeugung).state);
      for (int i = 0; i < pv_bar; i++) {
        it.print(i + 9, 1, "#"); // ASCII bar for generation
      }

# LCD Backlight Configuration
output:
  - platform: ledc
    pin: 21  # Adjusted GPIO pin for backlight
    id: lcd_backlight
    frequency: 5000Hz

light:
  - platform: monochromatic
    output: lcd_backlight
    name: "LCD Backlight"
    id: backlight
    default_transition_length: 1s
    restore_mode: ALWAYS_ON

It would make more sense to use a display with an I2C board, but I didn’t have one to hand.

For support, here is the connection diagram:

+-------------+------------+
| ESP32 GPIO  | LCD Pin    |
+-------------+------------+
| GND         | VSS        |
| 5V          | VDD        |
| Contrast    | V0         |
| GPIO 19     | RS         |
| GND         | RW         |
| GPIO 18     | E          |
| GPIO 4      | D4         |
| GPIO 16     | D5         |
| GPIO 17     | D6         |
| GPIO 5      | D7         |
| 5V          | A (LED +)  |
| GND         | K (LED -)  |
| GPIO 21     | Backlight  |
+-------------+------------+