IoTextra Input vs. Digital Input Modules — Specification Comparison

Introduction

This page compares IoTextra Input with digital input modules for microcontrollers, single-board computers, and automation systems.

IoTextra Input is shown in two configurations: as an I/O module for use with an external microcontroller or single-board computer, and paired with IoTsmart ESP32-S3. In the second configuration, it becomes a self-contained ESP32-S3 networked solution with Wi-Fi / MQTT and no external host controller required.

The comparison is based on specifications and capabilities published by the respective manufacturers. The table compares input count, isolation method, input type, maximum input voltage, power supply, control interface, interrupt line, hardware platform, software integrations, documentation, dimensions, connectors, and price.

The products in the table differ in channel count, architecture, and connection method. The purpose of the comparison is not to identify a single “best” module, but to make the practical differences between the available solutions easier to see based on published specifications.

Scroll the table horizontally to see all products.

Parameter IoTextra Input IoTextra Input & IoTsmart ESP32-S3 16 LV Digital Inputs 8-Layer Stackable HAT 8-Ch I2C Optically Isolated Digital Input (PR33-19) X-DI8 DI8 I2C Input Board Pi-SPi-8DI qPIO (8 inputs + 4 relays) IN-4 (KI-IN4)
Manufacturer MTH MTH Sequent Microsystems NCD NORVI KinCony Widgetlords AQEX KI Maker
Link link link to IoTextra Input
link to IoTsmart ESP32-S3 		link link link link link link link
1. Number of inputs 8 8 16 8 8 8 8 8 4
2. Galvanic isolation per-channel per-channel group per-channel group optocouplers; shared GND group per-channel per-channel
3. Input type DC, either polarity DC, either polarity AC/DC DC, either polarity DC, PNP/NPN dry contact / NPN (to 0 V) AC/DC contact / voltage level (factory configured) DC, either polarity
4. Max. input voltage, V 36 36 24 24 30 24 24 45 30
5. Power supply 5 V 5 V 5 V 12 V 24 V 9–24 V 5 V + field power up to 24 V AC/DC 5 V 3.3 V or 5 V
6. Control interface · units per stack GPIO / I²C (up to 16 per stack) Wi-Fi / MQTT I²C (up to 8 per stack); RS-485 / Modbus RTU I²C (up to 8 per stack) I²C / NORVI X bus (up to 4 per stack) I²C (up to 8 per stack) SPI (up to 8 per stack) GPIO GPIO
7. Interrupt line (INT) yes (I²C mode) yes (I²C mode) yes yes (INT pin on board) not stated no (not exposed) not stated not applicable — signals connect directly to GPIO not applicable — signals connect directly to GPIO
8. Host / hardware platform Raspberry Pi, Arduino Nano, ESP32-S3, RP2350, RP2040; IoTsmart / IoTbase Built-in ESP32-S3; no external host required Raspberry Pi via nodeLynk adapters: Arduino Uno/Nano/Micro/Due, Raspberry Pi, Feather, PC (USB) NORVI X CPU any I²C host (ESP32, KinCony controllers) Raspberry Pi Raspberry Pi Arduino, ESP32, STM32, Raspberry Pi
9. Software / integrations Node-RED, IoTflow, Tasmota, Home Assistant, Blynk Node-RED, IoTflow, Tasmota, Home Assistant, Blynk Python, Node-RED, Home Assistant, CODESYS, OpenPLC Python, Java, Arduino, Node-RED not stated ESPHome, Home Assistant, Arduino Python, Node-RED C++, Python no dedicated software
10. Documentation / open resources Documentation; schematic; GitHub Documentation; schematics for both modules; GitHub GitHub; schematic; STEP model GitHub Documentation Documentation; schematic GitHub; schematic; PCB files GitHub; STEP model; datasheet Documentation; datasheet; mechanical data
11. Module size, mm 47 × 56 47 × 56 93 × 56 101 × 62 81 × 104 90 × 50 85 × 56 65 × 56 65 × 50
12. Input connectors removable screw terminals, 3.5 mm pitch removable screw terminals, 3.5 mm pitch removable screw terminals, 3.5 mm pitch fixed screw terminals, 5.08 mm pitch push-in spring terminals removable screw terminals, 3.81 mm pitch fixed screw terminals, 5.08 mm pitch push-in spring terminals fixed screw terminals, 5.0 mm pitch
13. Price, USD (lowest-cost option, as of October 6, 2026) from $15.50 from $25.50 from $60.00 from $84.95 from $28.00 from $55.00 from $24.95 from $53.89 from $39.90 (2 pcs = 8 inputs)

Notes

  1. This comparison is based solely on manufacturer-published specifications and documentation. No comparative performance testing was performed.
  2. Both IoTextra Input configurations have identical electrical input specifications.
  3. The “Max. input voltage” row shows the maximum input voltage stated by the manufacturer. Switching thresholds and other logic-level detection parameters are not compared separately.
  4. For the KinCony DI8, the manufacturer states that the board uses optocoupler isolation. However, the published schematic shows a shared GND between the input and logic sections, so the table uses the wording “optocouplers; shared GND” rather than “galvanic isolation.”
  5. The AQEX qPIO has eight optically isolated digital inputs and also includes four relay outputs. This should be taken into account when comparing its price with modules intended only for digital input.
  6. The compared devices have different input counts: the Sequent Microsystems board has 16 inputs, the KI Maker IN-4 has 4 inputs, and the other listed solutions have 8 inputs.
  7. For the KI Maker IN-4, the price row shows the cost of two 4-channel modules, providing a total of 8 inputs.
  8. “Not stated” means that the corresponding specification could not be confirmed from the published documentation; it does not necessarily mean that the feature is absent.
  9. Prices are published retail prices as of October 6, 2026, and exclude shipping, taxes, and possible import charges. The price shown for IoTextra Input & IoTsmart ESP32-S3 is the combined price of the two components.
  10. The links in the table point to the product pages or documentation used as sources for the comparison.