An Simple IoT example – connected CO2 Sensor with WIZ550S2E

WIZ5500S2E and S-300

This IoT example shows how to connect CO2 sensor to your ethernet network, and how to send sensing data by using Serial-to-Ethernet gateway module as UDP client. Using S-to-E gatewat module, your device does not need any additional codes and hardware requried.

In this example, WIZ550S2E-232 as a S-to-E module and S-300 as a CO2 sonsor module are used.

  • WIZ550S2E-232: This module is a gateway module that converts RS-232 protocol into TCP/IP protocol and enables remote gauging, remote management of the device through the network based on the Ethernet and the TCP/IP by connecting to existing equipment with RS-232 serial interface.

  • S-300: This SO2 (Carbon Dioxide) sensor module designed by ELT ( and has available output with TTL-UART for sampling interval of about 3 seconds .

Block Diagram and Network Configurations

  • This figure is shown the block diagram and network configurations for this project.

    • IoT Sensor Node is made up as follows
      • S-to-E : WIZ550S2E-232
      • CO2 Sonsor : S-300
      • UDP Client embedded on S-to-E
    • Monitoring Server is composed as follows
      • UDP server : Hercules (TCP/IP utils) on PC


  • Serial-to-Ethernet Module : WIZ550S2E-232


    • Gateway module that converts RS-232 protocol into TCP/IP protocol
    • Serial to Ethernet Module based on W5500 & Cortex-M0
    • RJ-45 mounted, Pin-header type module
    • Serial signals : TXD, RXD, RTS, CTS, GND
    • Support the configuration method of AT command & Configuration tool program
    • Configuration tool program operates on Windows, Linux & MAC OS
    • Support the interface board for RS-232 and RS422/485
    • 10/100Mbps Ethernet & Max.230kbps serial speed
    • Support WIZ VSP (Virtual Serial Port) program
    • Dimension (mm) : 55(L) x 30 (W) x 23.49 (H)
  • Co2 Sensor: ELT Sensor : S-300


    • Non-Dispersive Infrared (NDIR) technology used to measure COâ‚‚levels.
    • Pre-calibrated
    • Available outputs : TTL-UART, I2C, ALARM, PWM/Analog Voltage.
    • Gold-plated sensor provides long-term calibration stability.
    • Installed re-calibration function
    • Operate as ACDL mode (Automatic Calibration in Dimming Light mode).
    • Manual Re-Calibration function is executable.
    • ROHS Directive- 2011/65/EU,[EN50581 : 2012,IEC 62321-3-1 : 2013]
    • Size : 33mmx33mmx13.1mm
    • Weight : 10 grams

Hardware connections

Three lines as below the may be connected for Sensor node.
The TXD in S-300 and RXD in WIZ550S2E should be connected together.

WIZ550S2E Direction S-300 JIG
VCC(baseboard) <— VCC (5V)
  • WIZ550S2E

    WIZ550S2E Pin Maps

  • S-300 JIG

    JIG S-300 Pin Maps


  • WIZ550S2E Side: Sensor Node

    WIZ550S2E Configuration

  • PC tools: Monitoring Server

    • Herdules

      > Hercules SETUP utility is useful serial port terminal (RS-485 or RS-232 terminal) , UDP/IP terminal and TCP/IP Client Server terminal. It was created for HW group internal use only, but today it’s includes many functions in one utility and it’s Freeware! With our original devices (Serial/Ethernet Converter, RS-232/Ethernet Buffer or I/O Controller) it can be used for the UDP Config.

    • Hercules download : version3.2.8

    • Hercules user guide : User Guide




  • UART frame of S-300

    S-300 output frame in UART

  • CO2 Data received from the Sensor node

    C02 Data received form Sensor node

  • CO2 Data shown in text format

    text type

  • CO2 Data shown in Hex format

    Hex type