Top products

STE2 LAN / WiFi Web thermometer/hygrometer icon
HWg-STE / HWg-STE plus
LAN (PoE) Web thermometer/hygrometer
HWg-Ares 12
GSM thermometer, Email (GPRS) & SMS
IP WatchDog2 Lite
PING restarter with SNMP status
IP WatchDog2 Lite
Poseidon2 xxxx
Sensors + I/O over Ethernet (Web, SNMP)
Damocles xxxx
I/O over Ethernet (SNMP, Modbus/TCP)
Serial port I/O over IP RS-232/485 + I/O over Ethernet icon
Water leak detector (WEB, SNMP, relay)
HWg-PWR 3/12/25
M-Bus to Ethernet smart gateway

On-line demos

STE2 Prague

Poseidon2 4002 Prague

Poseidon 2250 Prague

Damocles 2404 Prague

IP WatchDog Lite Prague

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What's new

22. 9.2016
AN43: Remote relay and water leak detection with HWg-WLD
HWg-WLD – LAN water flood detector can detect water leaks but does not directly feature relay outputs. This Application Note shows how to signal leaks using remote relay outputs (Damocles 1208).

9. 5.2016
HWg-CS58: Monitoring FM VHF transmitters using Poseidon2
The case study demonstrates remote monitoring of several FM VHF transmitters used by several radio stations around Cheb, Czech Republic. A Poseidon2 4002 unit is used for long-term remote monitoring of broadcasting quality along all signal propagation paths.

10. 9.2015
AN42: 0-20mA or 4-20mA current loop

When using LAN and GSM sensors by HW group, it is important to understand the difference between a 0..20mA current loop and a 4..20mA current loop. This Application Note explains the difference.

4-20mA / 0-20mA analog current loop is the output interface of many industrial sensors (water level measurement, current transformers, gas concentration sensors, and so on). The output current is proportional to the measured value.

19. 6.2015
New product: IP WatchDog2 Lite
The IP WatchDog2 Lite is a new generation of our popular IP WatchDog device.
One simple box with two relay outputs will restart your IP camera, router, WiFi AP or any other LAN device whenever it freezes or fails. No more crazy traveling just to push the reset button.

The IP WatchDog 2nd generation can use our central SMS gateway, connects to our portal and supports the SNMP protocol.

22. 5.2015
AN44: The SNMP v3 is now supported in all Poseidon2 units
The SNMP v3 is now supported in all Poseidon2 units. This is a major update that brings many advantages and improvements. The following text will explain all the advantages of the SNMP v3 and how to use it in Poseidon2 devices.

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HW group produces IP-enabled sensors

HW group s.r.o. is a manufacturer of sensors with IP interface. We provide solutions for remote monitoring and remote control over M2M. Our products are designed for IT, datacenters, industrial and security applications. More about us Free online portal for LAN and GSM sensors

Applications of our products:

Web portal for LAN / GSM sensors

We are the only manufacturer of LAN/GSM sensors for remote monitoring that offers a completely free online portal for our products. No software installation, no monthly fees.

All your sensors, at different premises and serving different customers, on a single screen. View charts, set alarm thresholds and check all the readings from anywhere. Mobile phone app available.

Remote environment monitoring over LAN

Need an IP thermometer that sends an e-mail when your air conditioning fails? Search no more. We offer several products for remote monitoring of various sensors over a LAN.

We supply LAN sensors for end users as well as professional 1U products for 19-inch cabinets. Sensors can be monitored with our simple software, or connected to third-party SNMP and SCADA systems.

  • HWg-STE: Simple LAN thermometer / hygrometer with SNMP (2 sensors)
  • HWg-STE plus: LAN thermometer with DI and SensDesk (4 sensors + I/O)
  • Poseidon2 3266: Remote sensor monitoring over a LAN (12 sensors + I/O)
  • Poseidon2 3268: Ethernet I/O and a sensor monitoring system (14 sensors + I/O)
  • Poseidon2 3468: IP thermostat for a DIN rail, 230V/16A-rated relay (14 sensors + I/O)
  • Poseidon2 4002: Datacenter environment monitoring (56 sensors + I/O)

Central GSM gateway for SMS alarms

Do you need to send alarms as text messages, independently of your Internet connection? Use a single HWg-SMS-GW2 text message gateway for LAN sensors by HW group.

Just a single SIM card and a single SMS gateway serve your entire LAN.

  • Can be used with Poseidon2, HWg-PWR, HWg-WLD, and the HWg-Trigger app.
  • Send text messages from your account at the portal.
  • Can be used to send SMS from the Nagios system.

GSM sensor monitoring + free Web portal

Do you need to monitor sensor states and readings at a place without a LAN connection? Use GSM sensors and the Ares12 unit. Thanks to its internal battery, monitoring works up to 10 hours without power.

Connect power, temperature or illumination sensors, water leak detectors, door contacts, and even industrial Pt100 or 4-20mA sensors.

Check the readings and even configure your Ares units at

  • Free mobile app for iPhone and Android.
  • Ares will alert you to a failing sensor or a power outage by texting up to 5 telephone numbers.
  • Windows software for data collection into a database, charts and export to MS Excel.
  • Reports and alarms by e-mail.

Water leak detection in a 2D area (WLD)

Our “WLD sensing cable” detects anything from just a few drops to a flood in a defined area.
Water is detected along its entire length. Ideal for monitoring rooms and data centers. The sensing cable can be easily extended at several points. Installation is quick and simple.

WLD sensing cable can be connected to these devices:

  • HWg-WLD (blue, LAN output)
    • Sends and e-mail or a SMS whenever water is detected along the cable.
    • Web interface, supports, SNMP, Modbus/TCP.
  • HWg-WLD Relay (white)
    • Relay output for signaling the status (Flooded / OK).
    • Can be connected as a sensor to Poseidon (LAN) and Ares (GSM) units.

Full RS-232 serial port + I/O over a LAN

Do you need to control a 230V/16A-rated relay or a full RS-232/485 serial port over a LAN? Use our IP Relay or I/O Controller products.

The serial RS-232 port at the device can be accessed from MS Windows as a VSP (Virtual Serial Port) just as a local COM port. Supports up to 250 remote serial ports. The HW VSP driver supports full RS-232 serial ports (9 pins).

  • Relay outputs can be controlled from the web interface of the device.
  • Device I/O can be connected to SCADA systems using Modbus/TCP.
  • I/O and serial port can be interconnected back-to-back among several devices.
  • A digital input at one device can control multiple digital outputs at other devices.

Target segments of our solutions


IP-enabled sensors