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https://github.com/Legolas-2025/Standalone-electricity-price-ticker.git
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Amir
6a6cf113b3
Wiring diagram and notes for the Electricity Price Ticker project, including optional peripherals and GPIO connections.
90 lines
3.2 KiB
Markdown
90 lines
3.2 KiB
Markdown
# Hardware Wiring Diagram (Seeed XIAO ESP32‑C3 Electricity Price Ticker)
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This document depicts the wiring for the **Electricity Price Ticker** project based on the connection instructions in `README.md`.
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It includes:
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- Required peripherals (LCD + button)
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- Supported optional peripherals (presence sensor + white LED + optional TTP223 touch button alternative)
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> Notes:
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> - Always connect **all grounds together** (ESP32 GND, LCD GND, sensor GND, LED GND).
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> - Verify your **XIAO ESP32‑C3 SDA/SCL pins** in the Seeed pinout; the sketch uses the board default I²C pins.
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> - **Important:** The **10 kΩ pull-down resistor on GPIO 9 is mandatory at all times** (even if the presence sensor is not connected).
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> - Button input is on **GPIO 4**. You may use either a **mechanical pushbutton** (default) *or* a **TTP223 touch module** (alternative), but not both in parallel unless you know what you’re doing.
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---
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## 1) Wiring overview (diagram)
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```mermaid
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flowchart TB
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MCU["Seeed XIAO ESP32-C3"]:::mcu
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LCD["20x4 I2C LCD 2004<br/>PCF8574 backpack<br/>I2C addr 0x27"]:::lcd
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%% Button input options (GPIO 4)
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GPIO4["GPIO 4 node<br/>(buttonPin input)"]:::io
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BTN["Mechanical pushbutton<br/>default option<br/>active LOW to GND"]:::btn
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TTP["TTP223 capacitive touch<br/>optional alternative<br/>OUT is HIGH when touched"]:::touch
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%% Presence-sensor input stage (GPIO 9) - always present
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GPIO9["GPIO 9 node<br/>(presencePin input)"]:::io
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RPD["10k pull-down resistor<br/>GPIO 9 to GND<br/>MANDATORY"]:::res
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PRES["RCWL-0516 presence sensor<br/>optional"]:::pres
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LED1["White indicator LED<br/>optional"]:::led
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PSU5V["5V supply<br/>USB-C or regulated 5V"]:::pwr
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V33["3.3V rail from XIAO"]:::pwr
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GND["Common GND"]:::gnd
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%% Power
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PSU5V -->|"5V"| MCU
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PSU5V -->|"5V or 3V3 if LCD supports"| LCD
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MCU -->|"3V3"| V33
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V33 -->|"3V3"| PRES
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V33 -->|"3V3"| TTP
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%% Grounds
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MCU --- GND
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LCD --- GND
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BTN --- GND
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TTP --- GND
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GPIO4 --- GND
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GPIO9 --- GND
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RPD --- GND
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PRES --- GND
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LED1 --- GND
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PSU5V --- GND
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%% I2C
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MCU -->|"SDA (board I2C SDA)"| LCD
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MCU -->|"SCL (board I2C SCL)"| LCD
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%% GPIO 4 button input stage (always)
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MCU -->|"GPIO 4 (buttonPin)"| GPIO4
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BTN -->|"button to GND"| GPIO4
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TTP -->|"OUT to GPIO 4 node"| GPIO4
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%% GPIO 9 presence input stage (always)
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MCU -->|"GPIO 9 (presencePin)"| GPIO9
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GPIO9 ---|"10k"| RPD
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RPD -->|"to GND"| GND
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PRES -->|"OUT to GPIO 9 node"| GPIO9
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%% White LED (single LED, directly from GPIO with series resistor)
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MCU -->|"GPIO 5 (whiteLedPin)"| LED1
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classDef mcu fill:#e8f0ff,stroke:#2b5fd9,stroke-width:1px,color:#000;
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classDef lcd fill:#fff4e5,stroke:#cc7a00,stroke-width:1px,color:#000;
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classDef btn fill:#eaffea,stroke:#2d8a2d,stroke-width:1px,color:#000;
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classDef touch fill:#e6fcff,stroke:#0077b6,stroke-width:1px,color:#000;
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classDef pres fill:#f3e8ff,stroke:#7b2cbf,stroke-width:1px,color:#000;
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classDef led fill:#ffe8ef,stroke:#c9184a,stroke-width:1px,color:#000;
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classDef res fill:#f5f5f5,stroke:#444,stroke-width:1px,color:#000;
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classDef pwr fill:#fff,stroke:#444,stroke-width:1px,color:#000;
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classDef gnd fill:#fff,stroke:#000,stroke-width:1.5px,color:#000;
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classDef io fill:#f5f5f5,stroke:#111,stroke-width:1px,color:#000;
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