HD2013.3 rain detector for rain status monitoring

Related instruments Weather stations

Shown below is an HD2013.3 rain detector from Delta OHM:

The rain detector can be used in an automated control system, e.g. to start a pump immediately when there is rain. It detects the rain status only (on/off of rain) but does not measure the rainfall amount (for this purpose, a rain gauge should be used). The detector detects rain by the wetness of the sensing part (the green color pad in the photo).

There are multiple types of output types available:

  • RS484 MODBUS-RTU or proprietary protocol
  • Analogue (0/4-20 mA by default or 0-10 V on request)
  • Voltage-free normally open contact

The voltage-free normally open contact can be connected to a relay to control other equipment.

Exhibition in WSH Forum on Heat Stress Management 2023

Related instruments Thermal comfort

OTM exhibited in WSH Forum on Heat Stress Management 2023 (25/05/2023, NUS Shaw Foundation Alumni House Auditorium), with the following two instruments exhibited:

  • HD32.3TC handheld instrument for WBGT measurement; key features:
    • With a large color touchscreen
    • Probes are interchangeable for various thermal comfort and micro-environment measurements
    • High accuracy
  • HD35EDWWBGT wall-mounted instrument for WBGT measurement; key features:
    • For long-term WBGT monitoring (up to 500 ml water capacity for the natural wet bulb temperature probe)
    • Suitable for outdoor installation
    • With a wireless data logger and it is possible to configure it with cloud connectivity
    • High accuracy

Shown below is a photo of our booth:

We are grateful for the exhibition opportunity and booth setup assistance provided by WSH Council and MOM, and also the exhibition items provided by Delta OHM.

Instrument for outdoor thermal comfort measurement (with solar panel and cloud service)

Related instruments Temperature & humidity, Air speed & wind, Thermal comfort

Shown below is an instrument integrated by OTM for outdoor thermal comfort measurement:

Below are the key features of the system:

  • Four quantities are measured: air temperature, relative humidity, airflow speed and globe temperature
  • Data logger included
  • With 4G connectivity and cloud service
  • With solar panel
  • Suitable for outdoor 24×7 monitoring
  • The height of the stand is adjustable in the range of 0.9 m to 1.5 m

Shown below is a screenshot of the cloud service portal:

Listed below are the key components in the systems:

Class A albedometer with data logger and tripod

Related instruments Pyranometers, Weather stations, Wireless & web data loggers

We recently supplied an ISO 9060 spectrally flat Class A albedometer with a data logger and tripod to a customer in Singapore. Shown below are a photo of the system and a screenshot of the data logging software.

Listed below are the components in the system:

Handheld data logger for UVC irradiance measurement

Related instruments Light & radiation

UVC disinfection is used in HVAC systems to eliminate germs and viruses, particularly in the current COVID-19 situation. UVC irradiance measurement is required for UVC radiation level control.

Shown below is a handheld data logger for UVC irradiance measurement, with the following components:

  • HD2102.2: handheld data logger for light and radiation measurement
  • LP471UVC: probe for UVC irradiance measurement

At the customer’s request, an ISO 17025 calibration certificate can be provided at an additional cost.

Wind speed & direction measurement with Delta Ohm HD53LS ultrasonic anemometer

Related instruments Weather stations, Wireless & web data loggers, Air speed & wind

Shown below is a wind speed and wind direction measurement system, with the following components:

  • HD53LS.S 2-axis ultrasonic anemometer with MODBUS-RTU output
  • HD35EDW-MB wireless data logger with MODBUS-RTU input

For this system, OTM also supplied a 2-meter-long stainless steel pole for mounting and wired/configured all instruments before delivery. The last step mechanical mounting was done by the end user. A USB dongle type base unit (HD35APD) was also included for manual downloading of monitoring data in a scheduled interval.

Cloud-based CO2 monitoring system for better air quality in COVID-19 situation

Related instruments Temperature & humidity, Wireless & web data loggers, Air quality sensors

A cloud-based CO2 monitoring system was configured by OTM for air quality monitoring in the COVID-19 situation.


The following two documents were followed in this application:

The CO2 level monitored is used as a proxy to justify the ventilation adequacy in the COVID-19 situation:

  • If the CO2 level is above 800 ppm, the ventilation may not be sufficient;
  • If the CO2 level is above 1100 ppm, the ventilation level is insufficient according to Singapore Standard SS554:2016.


Delta Ohm HD50 web data logger was used for this application. The model selected was HD50G1NBTV. It has built-in probes for CO2, temperature, and humidity measurement.

The instrument can meet all requirements specified by NEA/BCA. It also automatically uploads the data to Delta Ohm cloud via ethernet or wifi. Shown below are the results displayed in the cloud portal.

The instrument was pre-configured by OTM. The end user just needed to do the last-step mechanical mounting. All authorized users can access the results at the cloud portal with a browser and it is very convenient for facility managers who are busy with many things.

WBGT measurement with natural wet bulb temperature probe

Related instruments Temperature & humidity, Thermal comfort

An earlier post showed WBGT measurement with a combined temperature and humidity probe. With this configuration, the natural wet bulb temperature is calculated.

Shown below is a configuration of the same HD32.3TC instrument with a wet bulb temperature probe. In this case, the wet bulb temperature is directly measured, in compliance to ISO 7243.

HD32.3TC can be configured in various ways for thermal comfort, indoor air quality and microclimate analysis. Please refer to the data sheet of HD32.3TC for more details.