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Pool Controller 3.3
ESP32 Complete Wiring Schematic

ESP32 Complete Wiring Schematic

This document provides an additional, complete wiring diagram for the ESP32 setup with sensors, relays, resistors, and clock module (RTC).

The standard pins used in the firmware are:

  • PIN_DS_SOLAR = GPIO32
  • PIN_DS_POOL = GPIO33
  • PIN_RELAY_POOL = GPIO25
  • PIN_RELAY_SOLAR = GPIO26

1) Components (incl. clock and resistors)

  • 1x ESP32 Dev Board
  • 2x DS18B20 Temperature Sensor (Solar, Pool)
  • 2x Resistor 4.7kΩ (Pull-up for OneWire data lines)
  • 1x 2-Channel Relay Module 5V (preferably with optocoupler)
  • 1x RTC Module DS3231 (clock, optional)
  • 1x Power Supply 5V DC (sufficiently rated)
  • Wiring cables, terminals, optionally fuse/protection circuit on load side

2) Complete Schematic (Text Representation) 

+----------------------------------+
|              ESP32               |
|                                  |
| DS18B20 Solar DATA ---- GPIO32   |
| DS18B20 Pool  DATA ---- GPIO33   |
| Relay IN1 (Pool)  ----- GPIO25   |
| Relay IN2 (Solar) ----- GPIO26   |
| RTC SDA --------------- GPIO21   |
| RTC SCL --------------- GPIO22   |
| 3V3 ------------------- 3V3      |
| GND ------------------- GND      |
+----------------+-----------------+
|
| common ground (GND)
v
+----------------------+    +------------------------------+
| DS18B20 Solar        |    | DS18B20 Pool                 |
| VDD -> 3V3           |    | VDD -> 3V3                   |
| GND -> GND           |    | GND -> GND                   |
| DATA -> GPIO32       |    | DATA -> GPIO33               |
+----------+-----------+    +----------+-------------------+
|                           |
+--[4.7kΩ]---> 3V3          +--[4.7kΩ]---> 3V3

+----------------------------------+
| 2-Channel Relay Module (5V, opto)|
| IN1    <- GPIO25                 |
| IN2    <- GPIO26                 |
| VCC    <- 5V (or module logic)   |
| JD-VCC <- 5V (if separate)       |
| GND    <- GND                    |
+----------------+-----------------+
|
| Switching contacts
v
        Pool Pump / Solar Pump (AC)

+--------------------------------------+
| RTC DS3231 (optional, clock)         |
| VCC <- 3V3 (or 5V depending on module type) |
| GND <- GND                           |
| SDA <- GPIO21                        |
| SCL <- GPIO22                        |
+--------------------------------------+

3) Wiring Table

ComponentSignalESP32 PinAdditional Component
DS18B20 SolarDATAGPIO324.7kΩ pull-up to 3V3
DS18B20 PoolDATAGPIO334.7kΩ pull-up to 3V3
Relay Channel 1IN1GPIO25optional pull-down (fail-safe)
Relay Channel 2IN2GPIO26optional pull-down (fail-safe)
RTC DS3231 (optional)SDAGPIO21I2C bus
RTC DS3231 (optional)SCLGPIO22I2C bus
All componentsGNDGNDcommon ground routing
DS18B20 / RTCPower3V3clean decoupling
Relay modulePower5Vseparate load/logic recommended

4) Important Notes

  1. 230V/mains side of pumps must be wired according to applicable safety regulations.
  2. Route sensor cables separately from mains and relay cables.
  3. Check active logic of the relay module (active-low or active-high).
  4. For low-noise operation near the ESP32, provide additional decoupling (e.g., 100nF).
  5. The firmware uses NTP by default; the RTC module serves as an additional hardware clock for extensions/offline scenarios.

5) References

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