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README.md

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+# Dynamic Electricity Price Ticker (XIAO ESP32C3)
+
+This project displays day-ahead electricity prices for Slovenia (Energy-Charts API) on a 20x4 I2C LCD using a XIAO ESP32C3.
+It shows hourly averages and 15-minute detail for the current hour, and uses a white LED as a visual price indicator.
+
+## Features
+- Fetches day-ahead prices from Energy-Charts API (bzn=SI)
+- Displays current hour 15-minute detail on row 0 and hourly averages on remaining rows
+- LED patterns indicate price ranges (breathing, steady, blink, double-blink, triple-blink)
+- Wi‑Fi provisioning mode (AP + simple web UI)
+- Automatic NTP sync and DST-aware local time (CET/CEST for Ljubljana)
+
+## Important: DST / Timezone
+The firmware initializes timezone with the CET/CEST POSIX TZ string so `localtime()` and conversions of API unix timestamps respect DST transitions for Ljubljana:
+
+`configTzTime("CET-1CEST,M3.5.0/02:00,M10.5.0/03:00", "pool.ntp.org");`
+
+## Hardware and Pinout
+- Board: Seeed XIAO ESP32C3 (or compatible ESP32-C3 board)
+
+Pin usage (GPIO - function):
+- GPIO4  - Button (pushbutton to GND, internal pull-up enabled in code)
+- GPIO5  - White LED (use series resistor ~220-470Ω)
+- GPIO9  - Presence sensor (RCWL-0516) OUT
+- GPIO21 - Built-in status LED (WiFi indicator)
+- I2C (SDA / SCL) - LCD (LiquidCrystal_I2C), default address 0x27
+
+### Presence sensor (RCWL-0516) wiring
+- VCC -> 3.3V
+- GND -> GND
+- OUT -> GPIO9
+- Crucial: add a 10kΩ pull-down resistor between GPIO9 (OUT) and GND.
+  - Why: The RCWL-0516 output may float or remain high on boot; the pull-down ensures a defined LOW when idle and prevents the LCD backlight from unintentionally turning off or on.
+  - If you do not use a presence sensor, the firmware keeps the backlight ON by default.
+
+### Button wiring
+- One leg of the pushbutton to GPIO4, the other to GND. The code uses INPUT_PULLUP, so no external resistor is required.
+
+### White LED wiring
+- GPIO5 -> 220Ω resistor -> LED anode
+- LED cathode -> GND
+
+### I2C LCD wiring
+- SDA -> board SDA pin
+- SCL -> board SCL pin
+- VCC -> 5V or 3.3V depending on module
+- GND -> GND
+
+## Software
+- Espressif ESP32 Arduino core (tested with esp32 by Espressif Systems v3.3.2 in Arduino IDE)
+- ArduinoJson library
+
+## Notes
+- The project stores Wi‑Fi credentials in non-volatile storage (Preferences) and falls back to an AP provisioning portal if no credentials are saved.
+- The code applies power company fees and VAT to convert wholesale EUR/MWh prices to final consumer EUR/kWh by default. You can disable fees by setting APPLY_FEES_AND_VAT to false.
+
+## How to use
+1. Upload the firmware to your XIAO ESP32C3.
+2. If no Wi‑Fi credentials are stored, the board will start an AP `MyTicker_Setup` — connect and open the provisioning web UI.
+3. After Wi‑Fi and NTP sync, the sketch will fetch prices and start displaying them.
+
+## License
+- Add license information here if you want to publish this repository.