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© QuantAQ, Inc 2023 – V0.1.1

PRODUCT MANUAL

MODULAIR-PM

PRODUCT NAME MODULAIR-PM

VERSION 0.3.2

LAST UPDATED @September 20, 2023

LAST UPDATED BY @David Hagan

1. Introduction and Specs

MODULAIR™-PM provides real-time estimates of particulate matter concentrations (PM1, PM2.5, and PM10) and particle size distribution using a novel combination of multiple light-scattering-based particle sensors (patent pending).

1.1 Specifications

1.1.1 Air Quality Measurements

More on the above information can be found in the MODULAIR-PM data sheet.

1.1.2 Power and Comms

1.1.3 Operating Specs

*The device contains overheat protection for the laser which will shut off when the internal box temperature reaches approximately 45C. The device will automatically recover as soon as the device cools off and the internal box temperature is reduced below 40C.

1.2 Certifications

1.2.1 FCC 15(b)

The MODULAIR™-PM air quality sensor complies with part 15 of the FCC rules for class A devices. Operation is subject to the following two conditions: (1) this device may not cause harmful interference; (2) this device must accept any interference received, including interference that may cause undesired operation.

MODEL: MODULAIR-PM

Contains FCC ID: 2AEMI-BRN402

1.2.2 CE

The MODULAIR-PM complies with European Union EMC Directive 2014/30/EU and conforms to the following technical standards (EN 55011, EN 61326).

2. Installation and Hardware Setup

2.1 Unpacking

When you unpack your device, you should have received the following:

• MODULAIR-PM Particulate Matter Sensor
• Power supply and USB-C power cable
• Mounting hardware (flanges with 4 10-32 screws)
• 16 GB µSD card

If any of these components are missing, please contact QuantAQ via support.quant-aq.com. If the shipping box contains multiple devices, you will receive the correct multiple of each component from the list above.

2.2 Instrument Layout

2.2.1 Front Panel

The front panel of the device can be accessed by opening the lid of the enclosure. The panel provides access to the ON/OFF switch, Menu button, and LED indicator. Each component is labeled in Figure 1.

2.2.2 Core Circuit Board

Underneath the front panel (which can be opened by removing the four No. 6 screws in the four corners), you will find the Core Circuit Board and µSD circuit board. While it is unlikely you will ever need to touch this, it is worth pointing out a few key components.

2.3 Connections and Device Reg.

The MODULAIR-PM is shipped completely assembled, aside from the mounting hardware. Once the device is mounted and you have verified the power switch is in the OFF position, simply plug in the power supply and connect the USB-C cable in to the bottom of the device. Once the power cable is connected, simply flip the power switch to the ON position. Upon receiving power, the LED indicator (Figure 1) will flash green and eventually begin a sequence of slowly breathing cyan; this indicates the cellular connection is active and a session with the cloud server has begun. If the device is being powered on in a new location or has been powered off for an extended period of time, this may take some time to complete. The device will log data locally during this period and push the data to the server once a connection is established. If the LED indicator does not eventually begin breathing cyan, this indicates a cloud connectivity problem. Common errors and next steps can be found in Section 6.2.

To register your device, scan the QR code that is on the registration card you received with your device. It is easiest to complete this step using a cellphone or tablet with a working internet connection. A laptop with a functioning camera will also work, though maybe more difficult. It is also suggested that you first log in to the website on the device you will use to complete this process. To register your device:

1. Use your camera to scan the QR code. This will open a tab in your default browser and will direct you to the device registration page.
2. Enter the fields for the information that the form asks for and click "Continue"
3. Enter the claim code found on the same QR code card - it should be a 6-character alphanumeric code.
4. Follow the instructions on the form and enter in data for the device location and other metadata. All of these can be changed in the future through the dashboard, so don't worry if you can't answer all questions at this time.

2.4 Installation

The device can be mounted in a number of ways depending on the exact use and available mounting options available to you. The device is shipped with mounting flanges which can be used to easily mount the device to a number of surfaces. Each flange is secured to the back of the device with two 10-32 x 0.75" stainless steel screws (included). Each flange includes three slots with the dimensions found below.

Common installation approaches include:

• using high-strength zip ties to secure the device to a fence or post
• using screws to mount the device using the provided flanges

The complete box dimensions are:

• 7.04" x 7.04" x 5.72" (178.82 mm x 178.82 mm x 145.29 mm)

If a more secure approach is needed, a pole mount kit can be purchased directly from the supplier of the enclosures (Polycase part number PL-087).

3. Software Setup and Data

3.1 Data Structure and Outputs

There are three primary ways in which data can be accessed for the MODULAIR-PM:

1. Raw data is stored locally on the µSD card
2. Data can be downloaded from the QuantAQ Cloud Console
3. Data can be downloaded from the QuantAQ API

The data format’s are slightly different depending on which method you’ve used to access the data, each of which is documented below.

3.1.1 Data stored locally on the µSD Card

Data is collected and saved to the onboard µSD card every five seconds; every minute, these values are averaged and pushed to the cloud where they are available on the QuantAQ Cloud. It is unlikely you will ever need to use the locally saved data; however, it is there in case you need it. This section covers the locally stored data and how to understand it. When removing the µSD card to pull the data, make sure your device is turned OFF.

On the µSD card, you will find data files (with a prefix of DATA_YYYYMMDD.csv) and log files which are located in the logs directory. Log files contain debugging information about the onboard sensors and the cellular communications module. It is unlikely these logs will be useful to most users, though they are available to you if you would like to view them. It is highly recommended that you use the QuantAQ CLI (discussed below) to analyze them, as it will vastly reduce the amount of time needed.

Data files are written each day and can be read or analyzed using any programming language or spreadsheet program (e.g., Microsoft Excel). Each file begins with three meta-data rows describing the device model (row 1), device ID (row 2), and the device serial number (row 3). If you are automating your data analysis, you can skip these three rows. The fourth row contains the header information with the names for all columns. The remaining rows contain the data, where each row corresponds to a new 5-second sampling interval. The table below summarizes the columns.

3.1.2 Data downloaded from the QuantAQ Cloud Console

Data are pushed to the QuantAQ Cloud with 1-minute time resolution and can be downloaded via the QuantAQ Cloud Console. When downloading data, you are able to select whether you would like to download the raw data, the final data, or both the raw+final data. Generally, the final data is what is desired, as it contains the final, cleaned data that is ready for analysis. The raw data is well-suited for researchers trying to investigate specific questions. When downloaded, the data is exported as a csv and contains the following columns:

3.1.3 Data downloaded via the QuantAQ API

Data are available via the QuantAQ API at a 1-minute recording interval → the data available are the exact same as those available via the QuantAQ Cloud Console discussed above. The API is designed to allow engineers to build applications and map layers powered by the QuantAQ platform; however, it can also be a good way to automate data downloads, especially for large teams or lengthy download intervals. The data format is slightly different, as outlined below.

Each API call will return a paginated list of json objects with two keys: data and metaand will look something like the following:

"meta": {
    "first_url": "https://api.quant-aq.com/device-api/v1/devices/MOD-PM-00001/data/?page=1&per_page=50&limit=3",
    "last_url": "https://api.quant-aq.com/device-api/v1/devices/MOD-PM-00001/data/?page=1&per_page=50&limit=3",
    "next_url": null,
    "page": 1,
    "pages": 1,
    "per_page": 50,
    "prev_url": null,
    "total": 3
  }

The data object contains a list of all individual data objects for that page of data. You can query either the raw or the final data, both of which have different data values available. The final endpoint will return the following:

"data": [
    {
      "geo": {
        "lat": 33.7769,
        "lon": -84.4018
      },
      "met": {
        "pressure": 990.2,
        "rh": 10.54,
        "temp": 22.1
      },
      "model": {
        "pm": {
          "pm1": 8802,
          "pm10": 8804,
          "pm25": 8803
        }
      },
      "pm1": 1.293,
      "pm10": 1.297,
      "pm25": 1.297,
      "sn": "MOD-PM-00001",
      "timestamp": "2022-12-26T15:43:58",
      "timestamp_local": "2022-12-26T10:43:58",
      "url": "https://api.quant-aq.com/device-api/v1/devices/MOD-PM-00001/data/235414585"
    },
    {...},
    {...},
  ]

It contains several objects including the geo, met, and model objects. The descriptions of the individual data points are mapped to their respective columns in Section 3.1.2 above.

Note: If nothing appears in the right-hand column, the variable definition/name is the same

For raw data, the template is similar, but columns slightly different as described below.

"data": [
    {
      "flag": 0,
      "geo": {
        "lat": 33.7769,
        "lon": -84.4018
      },
      "met": {
        "pressure": 989.9,
        "rh": 10.32,
        "temp": 22.16
      },
      "neph": {
        "bin0": 210.25,
        "bin1": 63.083,
        "bin2": 3.75,
        "bin3": 0.417,
        "bin4": 0,
        "bin5": 0,
        "pm1": 0.333,
        "pm10": 0.5,
        "pm25": 0.5
      },
      "opc": {
        "bin0": 1.1973,
        "bin1": 0.0933,
        "bin10": 0,
        "bin11": 0,
        "bin12": 0,
        "bin13": 0,
        "bin14": 0,
        "bin15": 0,
        "bin16": 0,
        "bin17": 0,
        "bin18": 0,
        "bin19": 0,
        "bin2": 0.0242,
        "bin20": 0,
        "bin21": 0,
        "bin22": 0,
        "bin23": 0,
        "bin3": 0.007,
        "bin4": 0,
        "bin5": 0,
        "bin6": 0,
        "bin7": 0,
        "bin8": 0,
        "bin9": 0,
        "pm1": 0.18,
        "pm10": 0.21,
        "pm25": 0.21,
        "rh": 5.6,
        "temp": 28.9
      },
      "sn": "MOD-PM-00001",
      "timestamp": "2022-12-26T17:15:58",
      "timestamp_local": "2022-12-26T12:15:58",
      "url": "https://api.quant-aq.com/device-api/v1/devices/MOD-PM-00001/data/raw/235448331"
    },
		{...},
    {...},
  ],

3.2 Understanding and decoding the status flag

Each row of data contains a single-byte data flag that describes the current state of the device. Flags are stored as unsigned integers and contain encoded information about each of the sensors onboard. They are generated via a bitmask and can be decoded by reversing the procedure. To determine whether a specific flag is set, you can use the bitwise AND operation. If the flag's value is returned, then it is set. If a zero is returned, it is not set. This can seem complicated, so let's clear it up with a simple example.

Let's assume the value of the flag column is set to 4. We can perform a bitwise AND operation to check the result to see if FLAG_STARTUP was set (it wasn't). Below, we will check to see if the flag for the nephelometer is set (it is!).

# bit AND - is FLAG_STARTUP set?
>>> 4 & 1
0

# bit AND - is FLAG_NEPH set?
>>> 4 & 4
4

The following table describes the flags, their value, and what they mean.

3.3 Leveraging QuantAQ's Software Tools

To make data analysis easier, QuantAQ maintains a number of software programs designed to reduce the time you spend munging and cleaning your data. The most relevant piece of software is going to be the QuantAQ CLI (command line interface). The CLI can be used to easily concatenate files, merge files together, and de-code the flag and NaN bad data. It is quite simple to go from a large folder full of files to a clean, munged data file in less than a few commands. Full documentation and use cases can be found on the QuantAQ CLI website.

GitHub - quant-aq/cli: The QuantAQ CLI

This package provides easy-to-use tools to munge data associated with QuantAQ air quality sensors. Full documentation can be found here. This tool is built for Python 3.6.1+ and has the following key dependencies python = "^3.6.1" pandas = "^1.0.4" click = "^7.1.2" pyarrow = "^0.17.1" More details can be found in the pyproject.toml file at the base of this repository.

github.com

4. Maintenance and Service

There are no consumable or user-replaceable components to the MODULAIR-PM. If you believe a component is broken or not functioning correctly, please contact support@quant-aq.com for the next steps.

4.1 Reporting Issues

As a new product, it is likely that issues will arise with the hardware, firmware, software, or all three! We do our best to prevent issues from arising and will be timely in fixing any that do arise. If you experience an issue or have a suggestion related to the MODULAIR-PM hardware, please check the knowledge base. If you do not find the answer you're looking for in the knowledge base, you can open a ticket at support.quant-aq.com.

5. Changelog

5.1 Hardware Changes

5.2 Firmware Changes

6. Appendix

6.1 Wiring Diagrams

All cables used in the MODULAIR-PM are manufactured by Molex and available via most major distributors including DigiKey, Mouser, and Newark. The following table lists the part numbers and cable lengths for the cable connector; exact pinout diagrams can be found in the following subsections. Where applicable, "NC" means not connected.

6.1.1 CBL-1 | µSD Breakout Board

CBL-1 connects the Core Board to the µSD Breakout Board.

6.1.2 CBL-2 | RHT Breakout Board

CBL-2 connects the Core Board to the Relative Humidity and Temperature board on the sampling manifold.

6.1.3 CBL-3 | Particle Sensor 1

CBL-3 connects the Core Board to Particle Sensor 1.

6.1.4 CBL-4 | Particle Sensor 2

CBL-4 connects the Core Board to Particle Sensor 2.

6.2 LED Indicator Status and Meaning

The LED indicator on the front panel is used to communicate the status of the cellular and cloud communication status. The LED changes color and mode, each of which indicates a different state as outlined below. The rate at which the LED blinks comes in two flavors: blinking and breathing, where breathing implies a slow pulse where the color of the LED fades in and out.

On this page

• MODULAIR-PM
• 1. Introduction and Specs
• 1.1 Specifications
• 1.1.1 Air Quality Measurements
• 1.1.2 Power and Comms
• 1.1.3 Operating Specs
• 1.2 Certifications
• 1.2.1 FCC 15(b)
• 1.2.2 CE
• 2. Installation and Hardware Setup
• 2.1 Unpacking
• 2.2 Instrument Layout
• 2.2.1 Front Panel
• 2.2.2 Core Circuit Board
• 2.3 Connections and Device Reg.
• 2.4 Installation
• 3. Software Setup and Data
• 3.1 Data Structure and Outputs
• 3.1.1 Data stored locally on the µSD Card
• 3.1.2 Data downloaded from the QuantAQ Cloud Console
• 3.1.3 Data downloaded via the QuantAQ API
• 3.2 Understanding and decoding the status flag
• 3.3 Leveraging QuantAQ's Software Tools
• 4. Maintenance and Service
• 4.1 Reporting Issues
• 5. Changelog
• 5.1 Hardware Changes
• 5.2 Firmware Changes
• 6. Appendix
• 6.1 Wiring Diagrams
• 6.1.1 CBL-1 | µSD Breakout Board
• 6.1.2 CBL-2 | RHT Breakout Board
• 6.1.3 CBL-3 | Particle Sensor 1
• 6.1.4 CBL-4 | Particle Sensor 2
• 6.2 LED Indicator Status and Meaning