Analog I/O card DomESP series

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Overview
ESP8266 is a compact MCU with integrated WiFi used to expand I/O for home or industrial automation. Creasol DomESP1 is an expansion board for ESP8266 NodeMCU V3 modules (900 mil header pitch) providing digital inputs, one analog input, 4 relay outputs, I2C bus, 1‑Wire bus and 2 MOSFET outputs. DomESP2 offers the same electronics with plug-in terminal blocks for easier wiring.

Variants

• DomESP1 bare board: user supplies and mounts the ESP8266 NodeMCU (900 mil header pitch).
• DomESP1 with ESP8266 pre‑programmed (typically ESPEasy) and ready to use.
• DomESP2: same functions as DomESP1 but with removable terminal blocks for wiring convenience.

Key features

• 4 relay outputs (rated 250Vac, 10A max each); coil consumption ≈450 mW per relay.
• 1 analog input, 18V max, linear conversion function: %value%*0.01828 (useful for reading conversion).
• 1‑Wire bus (DS18B20 compatible) that can also act as a GPIO.
• I2C bus (SDA and SCL on terminal blocks) usable as GPIO; I2C pins are shared with MOSFET outputs (see notes).
• 2 open‑drain MOSFET outputs, 12A, 30V max — suitable for DC loads and LED strips with PWM dimming; MOSFETs share SDA/SCL GPIOs.
• Switching regulator to reduce consumption; input range 5–25 Vdc (recommended 8–25 Vdc for galvanic isolation).
• 5V and 3.3V outputs available on terminal blocks.
• LED indicators for I2C ports and relays, enabled by a Test button for wiring/firmware checks.
• Typical standby current (WiFi on, relays/MOSFETs OFF): ~80 mA @5V, ~40 mA @12V, ~20 mA @24V.

Important notes and limitations

• MOSFET outputs use the same GPIOs as I2C: I2C and MOSFET outputs cannot be used simultaneously.
• To enable a MOSFET output a PCB jumper must be soldered (MOS1 uses SDA, MOS2 uses SCL), reducing I2C availability.
• When switching inductive loads, use an external free‑wheeling Schottky diode and, if the supply is remote, add a 220 µF/appropriate voltage capacitor near the board to suppress spikes.
• For many relays, consider a Creasol relay module optimized for low standby consumption since each DomESP relay draws significant coil power.

Firmware and configurability
The ESP8266 module can run ESPEasy, ESPHome, Tasmota or other NodeMCU‑compatible firmware. Pre‑programmed units typically ship with ESPEasy ready to connect to WiFi and a home automation controller. Supported features depend on firmware (AP mode, WiFi setup, HTTP control, PWM via HTTP, etc.).

Installation and use cases

• Board is powered at low voltage (recommended 8–25 Vdc) to provide galvanic isolation from mains.
• Typical applications: pump control, temperature monitoring with DS18B20 sensors, LED strip dimming via MOSFET PWM, swimming pool management, multi‑zone heating control, energy/power monitoring integration.
• Example: set MOSFET PWM duty cycle via firmware HTTP call to dim LED strips.

Indicators and diagnostics
Built‑in LEDs for I2C and relay outputs assist status verification and troubleshooting; LEDs are enabled via the Test button.

Purchase / assembly options
DomESP1 is available as a bare board (customer supplies NodeMCU) or with the NodeMCU pre‑programmed. DomESP2 provides identical electronics but with removable terminal blocks for easier wiring.

Technical specifications

• Model: DomESP1 (DomESP2 = same board with plug‑in terminal blocks)
• Compatible MCU: ESP8266 NodeMCU V3 (900 mil header pitch); can be adapted for 1100 mil or Wemos D1 Mini by soldering.
• Relay outputs: 4 × relay, 250 Vac, 10 A max each; coil ≈450 mW per relay.
• MOSFET outputs: 2 × N‑channel open‑drain MOSFET, 12 A, 30 V max (suitable for 12/24 V LED strips); MOSFETs share SDA/SCL GPIOs.
• Analog input: 1 × analog input, 18 V max (conversion factor available).
• 1‑Wire: DS18B20 compatible bus (multiple sensors supported in parallel).
• I2C: SDA and SCL on terminal blocks (shared with MOSFETs if enabled).
• Power input: switching regulator, 5–25 Vdc input (typical 8–25 Vdc recommended for galvanic isolation).
• Power outputs: 5 Vdc and 3.3 Vdc on terminal blocks.
• Standby consumption (WiFi on, relays/MOSFETs OFF): typ. 80 mA @5V, 40 mA @12V, 20 mA @24V.
• LEDs: status LEDs for I2C and relays (enabled via Test button).
• Protection / recommendations: use free‑wheeling Schottky diode for inductive loads; place 220 µF / appropriate voltage capacitor near board if supply is remote; MOSx enable via solder jumper.
• Firmware support: ESPEasy (preprogrammed option), ESPHome, Tasmota, or other NodeMCU‑compatible firmware.