Test: Elsys ERS, room sensor for indoor air quality monitoring

December 13, 2018

With the help of the LoRaWAN room sensor Elsys ERS, indoor measurements can be recorded centrally via LoRaWAN. The integrated sensors send temperature, humidity, brightness, motion (PIR) and optional CO2 content via LoRaWAN in configurable intervals

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Product name: Elsys ERS
Category: Room sensor
Developer: Elektroniksystem i Umeå AB
Industrivägen 12
90130 Umeå
Sweden

The most important features at a glance

    • Class A LoRaWAN device
    • Semtech LoRaWAN Stack
    • Configurable transmission cycle
    • Configurable activation method (OTAA / ABP)
    • NFC configuration
    • Batteries; Lithium: 2x 3.6V AA
    • Radio Frequencies: LoRaWAN: EU863-870, US092-928, AS923, AU915-928, KR920-923
    • Accuracy: + -0.5 ° C, + -2% rh, + -45ppm
    • Resolution: 0.1 ° C, 0.1% RH, 1ppm
    • Dimensions: 86.00 x 25.50 x 86.00 mm

 

Unboxing: housing and processing

 

 

The Elsys ERS room sensor has an unobtrusive, white housing that resembles a light switch or heater temperature sensor. It is suitable for mounting on interior walls. The PIR motion and light sensor, visible to the front, also serves as a status indicator. On the basis of different-colored flashing patterns, the current operating status can be read according to the following diagram.

Connections

The Elsys ERS room sensor has no connections. Inside, one or two AA lithium batteries can be inserted. In principle, the sensors runs on oneAA lithium battery, the second battery only serves to extend the running time.

The newer room sensors from Elsys have an internal pin header which can be used to upload new firmware using the Elsys programming kit.

 

Configuration and operation

The configuration of the Elsys ERS room sensors is done via the NFC app “Sensor Settings” for Android devices.

With the help of the app, all other sensors from Elsys can be configured in addition to the ERS room sensor.

Reading out the keys required for the join process and selecting the desired activation method is done under the menu item “Sensor keys”.

Since it is a bit cumbersome to read out the sensor keys from the mobile app, you can take advantage of the “debug mode”. This mode can be activated in the ‘Application Menu’ (see screenshot). Together with the debug information, a “Send Debug” button appears at the end of the application, with which it is very easy to send all relevant information – including sensor keys – directly by e-mail.

The standard transmission interval can be changed directly on the start page. There is also the possibility to configure a single interval for each sensor. These intervals then represent a multiple of the standard transmission interval. The settings are made on the “Sensor sample times” page.

 

Special LoRaWAN parameters can be set on the “Advanced” or “Version 2 features” page. Among other things, the data rates (spreading factor) and the uplink port can be configured here.

Since theoretically third parties can also configure the sensor via the NFC Android App, the sensors should be locked after the configuration has been completed. The corresponding menu item is located on the left side under “Lock sensor“.

It is important to note that the optional CO2 sensor must be calibrated prior to installation. The calibration process should not take place indoors but rather in the fresh air. In order to start the calibration process, the “CAL CO2” button must be pressed on the homepage of the Android App.

Sensor data and payload

If the Elsys ERS room sensor has been successfully configured and connected to the LoRa network server (Join), the sensor data can now be read out. For this Elsys provides assistance in various ways.

On the https://www.elsys.se/en/elsys-payload/website, the individual sensor values can be read directly after entering the payload.

For integration on its own server, Elsys also makes this “decoder” available in the form of a Javascript file. This can be used directly on thingsHubor is already integrated here for all customers.

Conclusion

The Elsys ERS Room Sensor is a highly configurable LoRaWAN sensor that combines multiple probes into a single device. The configuration is done via a comprehensive NFC Android app. This means that reconfiguration after installation in the building requires a presence at the installation site. According to the website, the successor models ERS Desk and ERS Eye can also be configured via downlinks from the LoRa network server.

During our tests, the ERS room sensors did not behave deterministically with respect to the data rate (DR). Although we have set the data rate to a fixed value in the NFC app, the sensors have changed them at different times. This may be related to error detection in confirmed uplinks if the acknowledgments (ACK) are missing from the server. For unconfirmed uplinks this should not happen by itself.

The provision of the Javascript decoder is exemplary. Many other sensor manufacturers only provide documentation on the structure of the payloads here.

 

Reference

The device is available in our “thingHUB Market”.shop .

 

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