Intex Spa Smart Controller
ESPHome-based addon for the Intex PureSpa SB-H20 hot tub. Full bus protocol integration, automated heating/filtration, external filter coordination, Home Assistant.
A non-invasive addon that connects to the control panel bus via the 5-pin connector between mainboard and control panel. Uses a Seeed XIAO ESP32S3 Plus with external antenna for reliable backyard WiFi. Reads all temperatures, states, and sends button commands — same as the original control panel.
What It Does
Temperature Control
Read current water temp, set target temp (20-40°C), monitor heating status
Pump & Bubble Control
Toggle filter pump, bubble air pump, and heater from Home Assistant or web dashboard
External Filter Coordination
Coordinate Steinbach external filter with spa heating cycles to prevent E90 flow errors
Automated Scheduling
Set heating schedules, filtration cycles, heat-before-use times via Home Assistant
Home Assistant
Full ESPHome integration — climate entity, switches, sensors, automations
Standalone Dashboard
Built-in web interface accessible from any device, no HA required
Error Monitoring
Detect and report E90/E94/E95 error codes, send notifications
Your Specific Challenge
External Filter Dependency (E90)
Your Steinbach Comfort 50 external filter connects via Y-connector. When the Steinbach is OFF, not enough water flows through the Intex, triggering E90. The Steinbach must be running for Intex to work.
Current workaround: Keep Steinbach on 24h timer so it runs continuously. The ESP32 controller monitors/controls the Intex side. Optional future SwitchBot integration can control Steinbach remotely.
Why XIAO ESP32S3 Plus?
External Antenna for Outdoor Use
The XIAO ESP32S3 Plus has a U.FL external antenna connector — essential for reliable WiFi when the spa is in the backyard. The dual-core 240MHz architecture pins protocol handling to Core 0 while WiFi runs on Core 1. Plus USB-C, 16MB flash, and 8MB PSRAM.
Shopping List
| Part | Notes | Price |
|---|---|---|
| Seeed XIAO ESP32S3 Plus | Dual-core, USB-C, U.FL antenna connector | ~$10 |
| 2.4GHz External Antenna | U.FL connector, for outdoor range | ~$2 |
| BSS138 Level Shifter (4-ch) | 5V ↔ 3.3V bidirectional | ~$0.50 |
| 10µF Capacitor | Power supply filtering | ~$0.10 |
| Dupont/Hookup Wires | To 5-pin connector | ~$0 |
| IP65 Enclosure | Weather protection | ~$3 |
Total: ~$16 — Based on esp8266-intexsbh20, diyscip, and PicoW-Intex-PureSpa.