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 Raspberry Pi Pico W with PIO for reliable 100kHz timing. 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 Flow Issue (E90)
Your Steinbach Comfort 50 external filter connects via Y-connector and diverts water from the original Intex pump. This triggers the E90 low-flow error because the flow switch detects insufficient water passing through.
Solution: Smart coordination — don't run both pumps simultaneously during heating cycles. Home Assistant automations pause the external filter when the spa heater activates, and schedule external filtration for when heating is idle.
Why Pico W?
PIO solves the timing problem
The Intex bus runs at 100kHz and button presses require a precise 2µs pulse. ESP8266/ESP32 WiFi interrupts disrupt this timing, causing missed or double button presses. The Pico W's Programmable IO (PIO) handles the entire protocol in hardware, completely independent of WiFi or CPU.
Shopping List
| Part | Notes | Price |
|---|---|---|
| Raspberry Pi Pico W | WiFi, PIO for timing, 3.3V | ~$6 |
| 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: ~$10 — Based on PicoW-Intex-PureSpa, esp8266-intexsbh20, and diyscip.