Automatic Controller Pool Ionizer Embedded System

Project: ION Piscinas - BLE Smart Pool Ionizer System Target Retail Price: $600 USD / AUD Target Markets: Australia (RCM/ACMA compliance) & Brazil (Anatel compliance) Production Strategy: PCBA and assembly in China (e.g., JLCPCB, PCBWay) 1. Executive Summary ION Piscinas is a premium, digital, solid-state pool mineralizer. The ecosystem consists of two core components: The Physical Controller: A "faceless," completely sealed, rugged IP67 enclosure with no external buttons and no digital screens. It relies on internal memory to execute scheduled ionization tasks autonomously. The Mobile Application: A cross-platform smartphone app that serves as the exclusive user interface. It calculates ionization parameters and syncs them locally to the controller via Bluetooth. The primary engineering goals are exceptional outdoor durability, minimal manufacturing bill-of-materials (BOM) costs, zero monthly recurring server overhead, and an extremely simple regulatory certification pathway. 2. Hardware Specifications (PCBA) The printed circuit board assembly must be designed to withstand high-ambient heat, direct UV exposure, and high-humidity pool shed environments. Main Microcontroller: ESP32-WROOM module (or a direct equivalent Espressif pre-certified module). The design must utilize the onboard integrated antenna and factory shielding to inherit global modular RF certifications, bypassing expensive laboratory testing for Anatel and RCM wireless compliance. Power Delivery Circuitry: Solid-state H-Bridge IC (e.g., Texas Instruments DRV8871 or equivalent) capable of driving continuous DC current up to 2.0A to the electrodes. Mechanical relays are strictly prohibited to prevent mechanical wear and contact arcing. Current Sensing & Monitoring: Texas Instruments INA219 (or equivalent) high-side current/voltage monitor communicating via I2C. This sensor must sit directly on the output path to the copper electrodes to provide real-time milliampere telemetry to the microcontroller. Power Supply Module: Integrated AC-to-DC step-down transformer converting 110V/220V AC mains input down to 12V/24V DC for the output bridge and 3.3V DC for logic rails. Isolation Barrier: Galvanic isolation between the high-voltage AC input stage and the low-voltage DC water output stage is mandatory to guarantee absolute swimmer safety. 3. Physical Enclosure & Light Interface Because the controller contains no screens or buttons, the front panel is a singular, solid plastic face with the brand logo and three direct-mount indicator LEDs driven by the ESP32 GPIO pins: Power LED (Green): Illuminated solid when the system is connected to AC mains power. Bluetooth LED (Blue): Flashing when advertising/awaiting a wireless connection; illuminated solid blue when an active BLE session is established with a smartphone. System Status LED (Dual-Color Green/Red): * Breathing Green: Actively delivering current to the electrodes during a scheduled runtime window. Flashing Red: The system has encountered an active hardware fault. The bottom plate of the enclosure must feature exactly two heavy-duty liquid-tight compression cable glands: one for the incoming AC mains cord and one for the low-voltage output cable going out to the copper electrode tee. 4. Firmware Logic & Autonomous Control The ESP32 firmware must manage all operation metrics locally without reliance on an external data connection: Wireless Protocol: Bluetooth Low Energy (BLE) only. The standard Wi-Fi stack on the ESP32 must be explicitly compiled out or permanently disabled in firmware to save energy, minimize heat generation, and reduce local RF interference profile. Factory Current Locking: The firmware must support a production compile-time or factory-flashing flag that locks the controller into specific max amperage targets based on the physical kit size sold (e.g., Kit_Small = 0.25A, Kit_Large = 0.50A). The mobile app will never set the raw amperage output; it will only transmit time parameters. Automatic Polarity Reversal: To ensure even wear on the copper bars and eliminate calcification scale buildup, the firmware must reverse the current direction across the H-bridge every 30 minutes. To prevent cross-conduction, a 50-millisecond "break-before-make" safety delay (forcing PWM to absolute zero) must be executed before switching directions. Hardware Fault Self-Protection: While the system is actively ionizing (PWM active), the firmware must pull current data from the INA219. If the reading drops below 0.05A for 60 consecutive seconds (indicating an open circuit, dry cell, or completely depleted copper bars), the firmware must shut down power to the H-bridge immediately, switch the front LED to flashing red, and store a permanent "Electrode Fault" flag to broadcast during the next BLE sync.