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Readme.md

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 A fail-safe water flow monitoring module designed to protect CNC spindles and laser cutter tubes. It reads impulses from a ZJ-S401 water flow sensor, displays the real-time flow rate on an I2C OLED display, and triggers an active-low alarm to the CNC controller if the flow drops below a user-defined threshold.
 
+![Flow Controller Schema](schema.png)
+
+![Front](Flow_Controller_front.png)
+![Back](Flow_Controller_back.png)
+
 Designed in **KiCad v9**.
 
 ## Features
-* **Microcontroller:** WCH CH32V003J4M6 (RISC-V, SOP-8).
-* **Display:** 0.96" I2C OLED (SSD1315) with buttons.
+* **Microcontroller:** WCH CH32V003J4M6 (RISC-V).
+* **Display UI:** 8-pin connector for a custom OLED/Button panel (I2C SSD1315).
 * **Adjustable Threshold:** 2-button interface (Up/Down) using an analog resistor ladder (ADC) to save MCU pins.
-* **Fail-Safe Output:** N-channel MOSFET (MMBT7002) acting as an open-drain output. It actively pulls the CNC input to GND during normal operation. If power fails, wires break, or water stops, the connection opens and triggers the CNC alarm.
+* **Fail-Safe Output:** N-channel MOSFET (2N7002) acting as an open-drain output. It actively pulls the CNC input to GND during normal operation. If power fails, wires break, or water stops, the connection opens and triggers the CNC alarm.
 * **EMI Protection:** Hardware RC debouncing and noise filtering on the sensor input.
+* **Direct 5V Operation:** Powered directly from the CNC controller's 5V rail.
 
 ## Hardware Design (KiCad)
-The project contains the schematic and PCB layout files. 
-* **Power:** 5V DC Input from the CNC controller.
+* **Power:** 5V DC Input (via CNC connector J4).
 * **Sensor Compatibility:** ZJ-S401 (or similar 5V Hall-effect flow sensors).
-* **Output:** Connects directly to standard CNC active-low sinking inputs (internal optocoupler).
+* **Output:** 3-pin CNC interface (+5V, GND, ALARM_CNC). Connects directly to standard CNC active-low sinking inputs.
 
-### CH32V003 Pin Mapping
-| Pin (SOP-8) | Name | Function |
+### Microcontroller Pin Mapping (Per Schematic)
+| Pin | Schematic Net | Function |
 | :--- | :--- | :--- |
-| 1 | PC4 | Output: `ALARM_TRIGGER` (Drives MMBT7002 Gate) |
-| 2 | PD1 | SWIO (WCH-LinkE Programming) |
-| 3 | PC2 | I2C SCL (OLED Display) |
-| 4 | PC1 | I2C SDA (OLED Display) |
-| 5 | VDD | +5V Power |
-| 6 | VSS | Ground |
-| 7 | PA1 | Input: `FLOW_PULSE_MCU` (From Sensor via RC Filter) |
-| 8 | PA2 | ADC Input: `BUTTON_ADC` (2-Button Resistor Ladder) |
+| 1 | `FLOW_PULSE_MCU` | Input: Pulse counter from Flow Sensor (via RC Filter) |
+| 2 | `GND` | System Ground (VSS) |
+| 3 | `ALARM_TRIGGER` | Output: Drives the Gate of the 2N7002 MOSFET |
+| 4 | `+5V` | System Power (VDD) |
+| 5 | `I2C_SDA` | I2C Data (OLED Display) |
+| 6 | `I2C_SCL` | I2C Clock (OLED Display) |
+| 7 | `BUTTON_ADC` | ADC Input: 2-Button Resistor Ladder |
+| 8 | `SWIO` | WCH-LinkE Programming Interface |
 
 ## Firmware Logic (Overview)
-1. **Interrupts:** PA1 counts falling edges from the flow sensor. Flow (L/min) is calculated every second.
-2. **Failsafe:** If `Current_Flow >= Threshold`, PC4 is driven **HIGH** (MOSFET ON, CNC OK). If `Current_Flow < Threshold`, PC4 is driven **LOW** (MOSFET OFF, CNC Alarm).
-3. **UI:** ADC reads PA2 to detect button presses for adjusting the threshold.
+1. **Interrupts:** Pin 1 counts falling edges from the flow sensor. Flow (L/min) is calculated every second.
+2. **Failsafe:** If `Current_Flow >= Threshold`, Pin 3 is driven **HIGH** (MOSFET ON, CNC OK). If `Current_Flow < Threshold`, Pin 3 is driven **LOW** (MOSFET OFF, CNC Alarm).
+3. **UI:** ADC reads Pin 7 to detect button presses for adjusting the threshold.
 4. **Storage:** User-defined threshold is saved to MCU flash memory.
 
 ## Development & Programming
-To flash the CH32V003, you will need a **WCH-LinkE** programmer connected to the 3-pin SWIO header (3V3/5V, SWIO, GND).
+To flash the CH32V003, you will need a **WCH-LinkE** programmer connected to the 3-pin SWIO header `J1` (+5V, SWIO, GND).