commit c70b883817195481df068939ff0a231ea4fd7a04
Author: Malte <malte@drabesch.de>
Date:   Sun Dec 29 20:00:41 2024 +0100

    init

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..d8b4157
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+# Gitignore settings for ESPHome
+# This is an example and may include too much for your use-case.
+# You can modify this file to suit your needs.
+/.esphome/
+/secrets.yaml
diff --git a/.zed/tasks.json b/.zed/tasks.json
new file mode 100644
index 0000000..14a033d
--- /dev/null
+++ b/.zed/tasks.json
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+// Static tasks configuration.
+//
+// Example:
+[
+  {
+    "label": "esphome run wifi",
+    "command": "podman run --rm -it -v .:/config ghcr.io/esphome/esphome run dewpoint.yaml",
+    "use_new_terminal": false,
+    "allow_concurrent_runs": false,
+    "reveal": "always",
+    "hide": "never",
+    "shell": "system"
+  },
+  {
+    "label": "esphome run serial",
+    "command": "podman run --rm -it --device=/dev/ttyUSB0 -v .:/config ghcr.io/esphome/esphome run dewpoint.yaml",
+    "use_new_terminal": false,
+    "allow_concurrent_runs": false,
+    "reveal": "always",
+    "hide": "never",
+    "shell": "system"
+  }
+]
diff --git a/dewpoint.yaml b/dewpoint.yaml
new file mode 100644
index 0000000..6049470
--- /dev/null
+++ b/dewpoint.yaml
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+#<<: !include secrets.yaml
+esphome:
+  name: dewpointfan
+
+esp32:
+  board: esp32doit-devkit-v1
+  framework:
+    type: arduino
+
+# Enable logging
+logger:
+
+# Enable Home Assistant API
+api:
+  password: !secret ota_password
+
+ota:
+  - platform: esphome
+    password: !secret ota_password
+
+wifi:
+  ssid: !secret wifi_ssid
+  password: !secret wifi_password
+
+  # Enable fallback hotspot (captive portal) in case wifi connection fails
+  ap:
+    ssid: "Dewpoint Fan Fallback Hotspot"
+    password: !secret ota_password
+
+mqtt:
+  id: mqtt_client
+  topic_prefix: dewpoint
+  discovery: false
+  broker: mqtt.fd
+  port: 1883
+
+i2c:
+  sda: 21
+  scl: 22
+
+display:
+  - platform: lcd_pcf8574
+    dimensions: 20x4
+    address: 0x27
+    update_interval: 10s
+    lambda: |-
+      it.printf(0, 0, "Fan: %s", id(fan_relay).state ? "ON" : "OFF");
+      it.printf(0, 1, "Temp I/O: %.1f/%.1f", id(inner_temperature).state, id(outer_temperature).state);
+      it.printf(0, 2, "Hum I/O: %.1f/%.1f", id(inner_humidity).state, id(outer_humidity).state);
+      it.printf(0, 3, "Dew I/O: %.1f/%.1f", id(inner_dew_point).state, id(outer_dew_point).state);
+sensor:
+  - platform: dht
+    pin: 25
+    model: DHT22
+    temperature:
+      name: "Inner Temperature"
+      id: inner_temperature
+    humidity:
+      name: "Inner Humidity"
+      id: inner_humidity
+    update_interval: 10s
+  - platform: dht
+    pin: 26
+    model: DHT22
+    temperature:
+      name: "Outer Temperature"
+      id: outer_temperature
+    humidity:
+      name: "Outer Humidity"
+      id: outer_humidity
+    update_interval: 10s
+  - platform: template
+    name: "Inner Dew Point"
+    lambda: |-
+      float A = 17.27;
+      float B = 237.7;
+      float temp = id(inner_temperature).state;
+      float humidity = id(inner_humidity).state;
+      float alpha = ((A * temp) / (B + temp)) + log(humidity / 100.0);
+      return (B * alpha) / (A - alpha);
+    unit_of_measurement: °C
+    id: inner_dew_point
+    update_interval: 30s
+  - platform: template
+    name: "Outer Dew Point"
+    lambda: |-
+      float A = 17.27;
+      float B = 237.7;
+      float temp = id(outer_temperature).state;
+      float humidity = id(outer_humidity).state;
+      float alpha = ((A * temp) / (B + temp)) + log(humidity / 100.0);
+      return (B * alpha) / (A - alpha);
+    unit_of_measurement: °C
+    id: outer_dew_point
+    update_interval: 30s
+    icon: "mdi:thermometer-water"
+  - platform: template
+    name: "Fan state"
+    lambda: |-
+      uint8_t fan_state = 0;
+      float deltadp = id(inner_dew_point).state - id(outer_dew_point).state;
+      if (deltadp > 6.0) {
+        fan_state = 1;
+      }
+      if (deltadp < 5.0) {
+        fan_state = 0;
+      }
+      if (id(inner_temperature).state < 10.0) {
+        fan_state = 0;
+      }
+      if (id(outer_temperature).state < -10.0) {
+        fan_state = 0;
+      }
+      if (fan_state == 1) {
+        id(fan_relay).turn_on();
+      } else {
+        id(fan_relay).turn_off();
+      }
+      id(mqtt_client).publish_json("sensor/dewpointfan", [=](JsonObject root) {
+        root["inner_temp"] = id(inner_temperature).state;
+        root["inner_humidity"] = id(inner_humidity).state;
+        root["outer_temp"] = id(outer_temperature).state;
+        root["outer_humidity"] = id(outer_humidity).state;
+        root["inner_dewpoint"] = id(inner_dew_point).state;
+        root["outer_dewpoint"] = id(outer_dew_point).state;
+        root["fan_state"] = id(fan_relay).state;
+      });
+      return fan_state;
+    unit_of_measurement: ""
+    update_interval: 30s
+
+switch:
+  - platform: gpio
+    name: "Relay"
+    id: fan_relay
+    pin: 13
+
+captive_portal: