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lora-devices-ttn

Avelon - Wisely CarbonSense

The Wisely CarbonSense is an indoor room sensor to measure temperature, humidity, CO2 and atmosperic pressure.

Table of contents

  1. Specifications
  2. Documents / Links
  3. Wisely Product Overview
  4. Ordering Info
  5. Device specific Information
    1. LED blinking behaviour
    2. CO2 Sensor ABC Algorithm
    3. Handler Change
  6. Adding the Device to TTN
  7. Optional Settings
    1. Change sampling and transmission intervals
      1. SensorSampleTime
      2. CyclicTransmissionTime and CyclicTransmissionCounter
      3. CyclicTransmissionCounter
      4. Example configurations
    2. Change the led blinking behaviour
  8. Payload formatter

Specifications

  • Indoor device
  • Price ca. CHF 191.- (25.05.2022)
  • Sensors
    • Temperature, -10 … +80 [°C], ± 0.1 °C between 20 … 60 °C
    • relative Humidity, 0 … 95[%rH], ± 1.5 %rH between 10…80 %rH
    • CO2, 400 … 5’000 [ppm], ± 30 ppm + 3 % of measurement value
    • atmospheric pressure, [hPa], ± 1 hPa Attention: A series of Wisely CarbonSense (software version < 3.3) does not support air pressure measurement!
  • Power Supply: 1 battery, 3.6 V, 3600 mAh, (A), Li-SOCl₂
    • Expected life time: 3 … 8 years at roomtemperature
  • Size: 80 × 80 × 27 mm
  • Weight: 100 g

Documents / Links

Wisely Product Overview

SensorWisely StandardWisely CarbonSenseWisely AllSense (Simple Payload)Wisely AllSense (Extended Payload)
Atmospheric pressure✓✓*✓ *
Temperature✓✓✓✓
Humidity✓✓✓✓
VOC  ✓✓
Brightness  *✓ *
CO2 ✓✓✓
PIR/Presence  *✓ *
  • Due to limitations in payload length, these sensors are not activated by default

Ordering Info

Attention, there are four different versions of the same sensor which have different software loaded on them. Only the “Self-Managed” version works with the lcm application. Do not order the version “The Things Network”, it will not work with the lcm application.

  • Self-Managed -> that’s what you want to have!!!
    Data goes over the ttn network to the ttn server where the lcm application can fetch them, no monthly charges or fees.

Other variants which don’t work with TTN

  • Swisscom LPN
    Means that the data goes to the AVELON server via Swisscom low power network, monthly charges apply.
  • The Things Network
    Means that the data goes via ttn, but to the AVELON-server! No monthly charges. In this case the lcm application can’t access the data!
  • Building Automation
    Integration in the Avelon automation system, license fees system.

Ordering Link

Device specific Information

LED blinking behaviour

If a CO2 limit is exceeded, the LED on the front side of the device changes color. It blinks every SensorSampleTime (250 ms lighting, 500 ms pause - repeating 4 times).

CO2 valueLED Color
0 … 800green (on some devices this is deactivated)
801 … 1400blue
> 1400red

To deactivate or change the led behaviour see Change the LED blinking behaviour

CO2 Sensor ABC Algorithm

The ABC algorithm in CO2 sensors uses automatic base correction to reduce fluctuations and drifts in CO2 measurements. It continuously determines the zero point of the CO2 signal and adjusts it to 400 ppm (more or less the outside level) to ensure accurate and stable detection of CO2 concentrations in ambient air. This improves the long-term stability and reliability of CO2 sensors.

However, this means that the sensor must be exposed to clean air at least every 14 days. Otherwise the CO2 value will drift.

The sensor determines this base value during the first 2 weeks of operation and only provides usable values after this time. It is therefore important that the sensor has been exposed to the outside air for more than 2 hours during this time. If you want to accelerate this process, you can expose the sensor to the outside air and then send a downlink payload B2. This is how you end the 2 weeks period.

  1. In the TTN Console on the device view, select the device and change to the tab Messaging, select Downlink
  2. Change the FPort to 10
  3. Write B2 into the Payload field
  4. Press Send
  5. In the Data tab you should now see the scheduled telegram. The wisely sensor only receives downlink data after a transmission. Therefore start a transmission by pressing the button on the back of the sensor (push once short, green led will illuminate)

Handler Change

  • The Wisely sensors are per default configured for the Avelon Cloud, even if ordered as “self-managed”. Thats why we have to detach the device from the avelon cloud.
  1. Switch the device on and scan the QR-Code with e.g. a Mobile Phone (detailed information here)
  2. Click on the round information (i) symbol top right aside the sensor name
  3. Press Register for free
  4. Press create new account or login if you already have created an account
  5. When promted select Private and fill in the fields, then register
  6. Assign the device and skip the select location as well as alerting
  7. Change to your computer and log in to https://avelon.cloud/login
  8. Click your name > Devices on top right
  9. Your device should appear. Click on it to open the Device Configuration
  10. Click on the three small circles top right (More) and choose Configure LoraWAN Network Provider
  11. Choose Self-Managed and hit OK
  12. Press the blue floppy disk symbol top right to save the configuration.
  13. Copy the Device EUI, Application EUI and Application Key, we will need them later on.
  14. Now we have to reset the device manually approximately 1-2 minutes after closing the previous dialog by pressing the small button on the back of the device. 5 seconds -> Off , 2 seconds -> On

Adding the Device to TTN

  • Before a device can communicate via “The Things Network” we need to register it with an application.
  • The Avelon Wisely sensors use the so called “Over The Air Activation” (OTAA) and for a secure communication we will need to register the beforehand copied keys.
  1. Create a new application
  2. Under Overview click (+) Register device
  3. Under Input method select Enter end device specifics manually
  4. Under Frequency plan select Europe 863-870 Mhz (SF9 for RX2 - recommended)
  5. Under LoRaWAN version select LoRaWAN Specification 1.0.3
  6. As JoinEUI enter the Application EUI, fill in as well the Device EUI and the Application Key
  7. Set an end-device name
  8. Press Register end device
  9. Add the payload formatter
    • Switch to the tab Payload formatters
    • As Formatter type select Custom Javascript formatter
    • Copy/Paste the code from the payload Formatter section below
    • Click Save changes
  10. Now we have to reset the device manually by pressing the small button on the back of the device. 5 seconds -> Off , 2 seconds -> On
  11. The device should log in and you should see a green circle as Status in the tab Device Overview.
    • if not, please wait several hours and check again. The change of the handler can take a long time…

Optional Settings

Change sampling and transmission intervals

There are two configuration values, SensorSampleTime and CyclicTransmissionCounter. To change these two values, you have to send the device configuration telegrams (Downlink-Messages)

SensorSampleTime

The time interval in minutes at which the sensor queries the current values.

  1. In the TTN Console on the device view, select the device and change to the tab Messaging, select Downlink
  2. Change the FPort to 10
  3. Copy/paste the payload from the examples below, e.g. FF 01 0A into the Payload field
  4. Press Send
  5. In the Data tab you should now see the scheduled telegram. The wisely sensor only receives downlink data after a transmission. Therefore start a transmission by pressing the button on the back of the sensor (push once short, green led will illuminate)

CyclicTransmissionTime and CyclicTransmissionCounter

The time interval at which the sensor transmits the recorded measurement values. Must be a multiple of the sampling period.

To avoid overburdening the battery of the device, the smallest permissible time interval is 10 minutes.

The CyclicTransmissionTime cannot be configured. Instead, a counter can be configured.

CyclicTransmissionTime = CyclicTransmissionCounter × SensorSampleTime

This setting cannot be configured. But instead the value CyclicTransmissionCounter can be set.

CyclicTransmissionCounter

Per default the CyclicTransmissionCounter is set to 60, which means the device in default configuration sends data every 60 minutes (60 × 1 min = 60 min).

The device sends the data cyclically. When a certain number of samples has been taken, the measured values are sent. The CyclicTransmissionCounter is therefore the number of samples that are to be sent together.

CyclicTransmissionCounter = CyclicTransmissionTime / SensorSampleTime

Per default the CyclicTransmissionCounter is set to 60, so every 1h a set of 6 measurements of all sensors gets transmitted.

  1. In the TTN Console on the device view, select the device and change to the tab Messaging, select Downlink
  2. Change the FPort to 10
  3. Copy/paste the payload from the examples below, e.g. FF F0 06 into the Payload field
  4. Press Send
  5. In the Data tab you should now see the scheduled telegram. The wisely sensor only receives downlink data after a transmission. Therefore start a transmission by pressing the button on the back of the sensor (push once short, green led will illuminate)

Example configurations

Example 1 (default config)
This configuration makes sense if the LED is used, so the occupant gets every minute a flashing LED. If the LED gets deactivated anyway, the sampling rate is unecessary high.

  • SensorSampleTime = 1 (HEX 01 -> FF 01 01) Every 1 min a sensor sample, every 10 min an averaged measurement.
  • CyclicTransmissionCounter = 60 (HEX 3C -> FF F0 3C) After 60 samples a data transmission, that means 6 averaged measurements in the payload, transmitted every 60 minutes.

Example 2
This configuration makes sense if the LED is used and the values should arrive faster than every hour. This has an impact on battery life! If the LED gets deactivated anyway, the sampling rate is unecessary high.

  • SensorSampleTime = 1 (HEX 01 -> FF 01 01) Every 1 min a sensor sample, every 10 min an averaged measurement.
  • CyclicTransmissionCounter = 20 (HEX 14 -> FF F0 14) After 20 samples a data transmission, that means 2 averaged measurements in the payload, transmitted every 20 minutes.

Example 3
This configuration makes sense if the smallest possible measuring rate is required and the LED gets deactivated.

  • SensorSampleTime = 10 (HEX 0A -> FF 01 0A) Every 10 min a sensor sample, every 10 min an averaged measurement.
  • CyclicTransmissionCounter = 6 (HEX 06 -> FF F0 06) After 6 samples a data transmission, that means 6 averaged measurements in the payload, transmitted every 60 minutes.

Example 4
This configuration makes sense if a long battery life is required and the LED gets deactivated. The sensor acts as a logger and the data is not real time, but battery life is optimized. Small changes in sensor values cannot get detected, so the accuracy is slightly lower. E.g. the impact of an opened window might not be visible in the temperature data.

  • SensorSampleTime = 60 (HEX 3C -> FF 01 3C) Every 60 min a sensor sample, every 60 min an averaged measurement.
  • CyclicTransmissionCounter = 24 (HEX 18 -> FF F0 18) After 6 samples a data transmission, that means 6 averaged measurements in the payload, transmitted every 360 minutes (6 hours).

Change the led blinking behaviour

With the following procedure you can deactivate the LED

  1. Select the device and change to the tab Messaging, select Downlink
  2. Change the FPort to 10
  3. Copy/paste 06 06 0B 03 20 00 00 FF 00 into the Payload field for deactivating the blue led
  4. Press Send
  5. The wisely sensor only receives downlink data after a transmission. Therefore start a transmission by pressing the button on the back of the sensor (push once short, green led will illuminate)
  6. Copy/paste 06 06 0B 05 78 FF 00 00 00 into the Payload field for deactivating the red led
  7. Press Send
  8. Press again the button on the back of the sensor
  • Now the led should not blink anymore.
  • To reset the behaviour exchange the last byte with 01 instead of 00:
    • 06 06 0B 03 20 00 00 FF 01
    • 06 06 0B 05 78 FF 00 00 01

Look at the Wisely LED Payload Creator Excel to create the payload information.

Further info in the payload description .

Payload formatter

function getValues(bytes, measurement, byteIndices, deviceType, datasetCount, datasetLength, payloadOffset) {
  var decoded = [];
  var measurementByteLengths = {"pressure_hPa": 2, "temperature_degrC": 2, "humidity_perc": 1, "voc_index": 2, "brightness_lux": 2, "co2_ppm": 2, "presence_min": 2};
  var divFactors = {"pressure_hPa": 10.0, "temperature_degrC": 10.0, "humidity_perc": 2.0, "voc_index": 1.0, "brightness_lux": 1.0, "co2_ppm": 1.0, "presence_min": 1.0};

  if (measurement in byteIndices[deviceType]) {
    var byteIndexValue = byteIndices[deviceType][measurement];

    for (var i = 0; i < datasetCount; i++) {
      var byteIndex = i * datasetLength + byteIndexValue + payloadOffset;
      if (measurementByteLengths[measurement] === 2) {
        decoded.push((bytes[byteIndex] << 8 | bytes[byteIndex + 1]) / divFactors[measurement]);
      } else {
        decoded.push((bytes[byteIndex]) / divFactors[measurement]);
      }
    }
  }
  return decoded;
}

function decodeUplink(input) {
  var deviceType = "CarbonSense";
  var samplingRate = 10; //minutes
  var datasetLengthDict = {
    "Standard": 5,
    "CarbonSense": 7,
    "AllSense": 7,
    "AllSenseExt": 13
  };
  var byteIndices = {
    "Standard": {"pressure_hPa": 0, "temperature_degrC": 2, "humidity_perc": 4},
    "CarbonSense": {"pressure_hPa": 0, "temperature_degrC": 2, "humidity_perc": 4, "co2_ppm": 5},
    "AllSense": {"temperature_degrC": 0, "humidity_perc": 2, "voc_index": 3, "co2_ppm": 5},
    "AllSenseExt": {"pressure_hPa": 0, "temperature_degrC": 2, "humidity_perc": 4, "voc_index": 5, "brightness_lux": 7, "co2_ppm": 9, "presence_min": 11}
  };
  var payloadOffset = 1; // Offset of battery information, offset before datasets
  var warnings = [];
  var errors = [];
  
  if(datasetLengthDict[deviceType] === undefined){
    errors.push("Error: Typo in deviceType configuration in payload decoder");
  }
  
  if((input.fPort === 5) || (input.fPort === 6)){
    // Battery status and percent
    var batVal = input.bytes[0];
    var batteryPerc;
    if((batVal >= 30) && (batVal < 254)){
      batteryPerc = Math.round(batVal / 254.0 * 100.0 * 10) / 10;
    }else if((batVal < 30) && (batVal > 1)){
      batteryPerc = Math.round(batVal / 254.0 * 100.0 * 10) / 10;
      warnings.push("Battery Warning: Low state");
    }else if((batVal === 1)){
      batteryPerc = 1;
      warnings.push("Battery Warning: No further battery capacity available");
    }else if(batVal === 254){
      batteryPerc = 100.0;
    } else{
      batteryPerc = 0.0;
      warnings.push("Battery Warning: Could not acquire the voltage");
    }
      
    if(input.fPort === 6 && deviceType !== "AllSense"){
      warnings.push("Warning: deviceType in payload decoder is not set to AllSense");
    }
    
    var datasetLength = datasetLengthDict[deviceType];
    var datasetCount = (input.bytes.length - 2) / datasetLength;
    var readings = [];
    
    if(!Number.isInteger(datasetCount)) {
      errors.push("Error: datasetCount is not a whole number!");
    } else {
      for (var i = 0; i < datasetCount; i++) {
        var reading = { battery_perc: batteryPerc };
        
        for (const [key, value] of Object.entries(byteIndices[deviceType])) {
          var decoded = getValues(input.bytes, key, byteIndices, deviceType, 1, datasetLength, payloadOffset + i * datasetLength);
          if (decoded.length > 0) {
            reading[key] = decoded[0];
          }
        }
        reading["offset"] = (datasetCount - i - 1) * samplingRate * (-1); 
        readings.push(reading);
      }
    }
  } else {
    errors.push("Unknown fPort");
  }

  return {
    data: readings,
    warnings: warnings,
    errors: errors
  };
}