MODULAIR™-PM Product Manual [v0.2.0]

MODULAIR™-PM Product Manual [v0.2.0]

Product Name MODULAIR™-PM

Version 0.2.0

Last Updated Feb 5, 2021

Last Updated by

David Hagan

1. Introduction and Specifications

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

Parameter

, , and

Particle size distribution

Temperature

Relative Humidity

Pressure

Range

0 to 2,000 µg/m3

0.35 to 40.0 µm (24 size bins)

-40 to 85 ºC

0 to 100 %

300 to 1,100 hPa

Accuracy

Not yet determined.

Not yet determined.

± 1 ºC

± 3%

± 1.7 hPa

1.1.2 Power and Communication

Parameter

Power

Communication

Data

Details

5V, 2A (supply)

500 mA average consumption

LTE (North America)

3G/2G (Worldwide)

Web interface (quant-aq.com)

Programmatic access (QuantAQ Cloud API)

Local Storage (16 GB on-board µSD card)

1.1.3 Operating Specifications

Parameter

Weatherproof rating

Operating temperature

Operating humidity

Dimensions

Weight

Details

IP68

-20 to 60 ºC

5 to 95 %, non-condensing

6.59" x 6.59" x 5.11"

4 lbs (1.8 kg)

1.2 Certifications

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

image

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.

Figure 1. MODULAIR-PM Front Panel consisting of an LCD screen, power ON/OFF switch, LED indicator, menu button, and access to the on-board µSD card.
Figure 1. MODULAIR-PM Front Panel consisting of an LCD screen, power ON/OFF switch, LED indicator, menu button, and access to the on-board µSD card.

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.

Figure 2. Core Circuit Board including connectors for two particle sensors, a relative humidity, temperature, and pressure sensor, and the µSD circuit board. This image is here for reference only. Users are not expected to need to ever though the circuitry.
Figure 2. Core Circuit Board including connectors for two particle sensors, a relative humidity, temperature, and pressure sensor, and the µSD circuit board. This image is here for reference only. Users are not expected to need to ever though the circuitry.

2.3 Connections and Device Registration

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 working internet connection. A laptop with a functioning camera will also work, though may be more difficult. It is also suggested that you first login 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 meta data. 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 1/4-20 x 0.5" 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).

Figure 3. Dimensions for the mounting holes for the provided mounting flanges.
Figure 3. Dimensions for the mounting holes for the provided mounting flanges.

3. Software Setup and Data

Data is collected and saved to the on-board 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 on-board 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.

Column

timestamp_iso

sample_rh

sample_temp

sample_pres

bin0

bin1

bin2

bin3

bin4

bin5

bin6

bin7

bin8

bin9

bin10

bin11

bin12

bin13

bin14

bin15

bin16

bin17

bin18

bin19

bin20

bin21

bin22

bin23

bin1MToF

bin3MToF

bin5MToF

bin7MToF

sample_period

sample_flow

opc_temp

opc_rh

opc_pm1

opc_pm25

opc_pm10

laser_status

pm1_std

pm25_std

pm10_std

pm1_env

pm25_env

pm10_env

neph_bin0

neph_bin1

neph_bin2

neph_bin3

neph_bin4

neph_bin5

flag

fw

connection_status

Unit

%

ºC

hPa

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

p/cm3

ml/s

ml/s

ml/s

ml/s

s

ml/s

ºC

%

µg/m3

µg/m3

µg/m3

µg/m3

µg/m3

µg/m3

µg/m3

µg/m3

µg/m3

p

p

p

p

p

p

Description

The sample timestamp in ISO format

Sample relative humidity

Sample temperature

Sample pressure

Number of particles per cubic cm in bin0 (0.35 - 0.46 µm)

Number of particles per cubic cm in bin1 (0.46 - 0.66 µm)

Number of particles per cubic cm in bin2 (0.66 - 1.0 µm)

Number of particles per cubic cm in bin3 (1.0 - 1.3 µm)

Number of particles per cubic cm in bin4 (1.3 - 1.7 µm)

Number of particles per cubic cm in bin5 (1.7 - 2.3 µm)

Number of particles per cubic cm in bin6 (2.3 - 3.0 µm)

Number of particles per cubic cm in bin7 (3.0 - 4.0 µm)

Number of particles per cubic cm in bin8 (4.0 - 5.2 µm)

Number of particles per cubic cm in bin9 (5.2 - 6.5 µm)

Number of particles per cubic cm in bin10 (6.5 - 8.0 µm)

Number of particles per cubic cm in bin11 (8.0 - 10.0 µm)

Number of particles per cubic cm in bin12 (10.0 - 12.0 µm)

Number of particles per cubic cm in bin13 (12.0 - 14.0 µm)

Number of particles per cubic cm in bin14 (14.0 - 16.0 µm)

Number of particles per cubic cm in bin15 (16.0 - 18.0 µm)

Number of particles per cubic cm in bin16 (18.0 - 20.0 µm)

Number of particles per cubic cm in bin17 (20.0 - 22.0 µm)

Number of particles per cubic cm in bin18 (22.0 - 25.0 µm)

Number of particles per cubic cm in bin19 (25.0 - 28.0 µm)

Number of particles per cubic cm in bin20 (28.0 - 31.0 µm)

Number of particles per cubic cm in bin21 (31.0 - 34.0 µm)

Number of particles per cubic cm in bin22 (34.0 - 37.0 µm)

Number of particles per cubic cm in bin23 (37.0 - 40.0 µm)

Time of flight for particles in bin1

Time of flight for particles in bin3

Time of flight for particles in bin5

Time of flight for particles in bin7

The sample period

The sample flow rate

The internal temperature of the OPC

The internal relative humidity of the OPC

The factory computed value for PM1 from the OPC

The factory computed value for PM2.5 from the OPC

The factory computed value for PM10 from the OPC

The status of the laser

The factory computed value for PM1 from the nephelometer

The factory computed value for PM2.5 from the nephelometer

The factory computed value for PM10 from the nephelometer

The factory computed value for PM1 from the nephelometer

The factory computed value for PM2.5 from the nephelometer

The factory computed value for PM10 from the nephelometer

Number of particles in bin0 for the nephelometer

Number of particles in bin1 for the nephelometer

Number of particles in bin2 for the nephelometer

Number of particles in bin3 for the nephelometer

Number of particles in bin4 for the nephelometer

Number of particles in bin5 for the nephelometer

The status flag corresponding to this sample

The current firmware version

A boolean describing the state of the cellular connection

3.1 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 on board. 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.

Flag

FLAG_STARTUP

FLAG_OPC

FLAG_NEPH

FLAG_RHTP

Value

1

2

4

8

Why is it set?

This flag is set when the device powers on.

This flag is set when the OPC has indicated the data failed to transfer correctly. This can be caused by the fan being off, the laser being off, or the checksum not validating properly.

This flag is set when the nephelometer has indicated the data failed to transfer correctly.

This flag is set when the relative humidity, temperature, and pressure sensor has failed.

What to do?

Remove any rows where this flag is set.

Remove any rows where this flag is set.

Remove any rows where this flag is set.

Remove any rows where this flag is set.

3.2 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.

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 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

Version 0.2.0 [January 2021]

  • The LED screen was removed to mitigate issues and confusion around it being used for real-time information.
  • The enclosure was updated to a new version to reduce production burdens
  • A new chassis was developed as we scaled production → we went from 3D printing to a bent metal chassis

5.2 Firmware Changes

Version 8 (v8) [January 11th, 2021]

Firmware version 8 is the first to support batch 2 of the MODULAIR-PM sensors (w.o. LED screen).

  • Removed support for the LED screen
  • Updated firmware to support a newer release of the RTOS

Version 7 (v7) [December 10th, 2020]

  • Improved error logging to the µSD card
  • Added a cell timeout to help restart connections when stalled
  • Improved cellular stability via improved monitors and restart capabilities

Version 6 (v6) [October 27th, 2020]

  • Fixed a bug with the auto-restart of the RHTP sensor when it fails or times out.

Version 5 (v5) [October 12th, 2020]

Firmware version 5 is the first production release of the device firmware. No changes are listed at this time.

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.

Label

CBL-1

CBL-2

CBL-3

CBL-4

N. Pins

8

4

8

6

Manufacturer

Molex

Molex

Molex

Molex

Man. PN

530470810

530480410

530470810

5015680607

DigiKey PN

WM1748-ND

WM1744-ND

WM1748-ND

WM7897CT-ND

Cable Length (mm)

304.8

304.8

304.8

304.8

6.1.1 CBL-1 µSD Breakout Board

CBL-1 connects the Core Board to the µSD breakout board.

Untitled

Pin NumberLabelTypeDescription
1
VCC
POW
Power in; 4.2VDC (5.5 V max)
2
EN
IN
Linear voltage regulator enable pin (active high)
3
CLK
BD
Serial clock (SPI)
4
MOSI
BD
Master out, slave in (SPI)
5
CS
IN
Chip select (SPI)
6
MISO
BD
Master in, slave out (SPI)
7
NC
8
GND
GND
Ground

6.1.2 CBL-2 Relative Humidity, Temperature, and Pressure Breakout Board

CBL-2 connects the Core Board to the RHTP sensor located on the sampling manifold.

Untitled

Pin NumberLabelTypeDescription
1
VCC
POW
Power in; 3.3V
2
SDA
DATA
Serial data line (I2C)
3
SCL
DATA
Serial clock line (I2C)
4
GND
GND
Ground

6.1.3 CBL-3 Particle Sensor 1

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

Untitled

Pin NumberLabelTypeDescription
1
VCC
POW
Power in; 5V
2
GND
GND
Ground
3
NC
4
NC
5
TXD
DATA
Serial data
6
NC
7
NC
8
NC

6.1.4 CBL-4 Particle Sensor 2

CBL-4 connect the Core Board to Particle sensor 2.

Pin NumberLabelTypeDescription
1
VCC
POW
Power in; 5V
2
SS
IN
Slave select pin (SPI)
3
MOSI
DATA
Master out, slave in (SPI)
4
MISO
DATA
Master in, slave out (SPI)
5
CLK
DATA
Serial clock (SPI)
6
GND
GND
Ground

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.

Untitled

LED ColorBlink PatternModeDescription
Green
Blinking
Looking for internet
If your device is blinking green, it is trying to connect to the cellular network. There is no need to take any action.
Breathing
Cloud not connected
If your device is breathing green, it has a cellular connection but has not been able to connect to the cloud.
Cyan
Blinking
Connecting to the cloud
Blinking cyan indicates the device has a cellular connection and is attempting to connect to the cloud. There is no need to take any action. This will happen each time on device startup.
Breathing
Connected
When your device is breathing cyan, everything is good and you are happily connected to the internet and the QuantAQ Cloud.
Magenta
Blinking
Firmware Update
When your device is blinking magenta, it is undergoing an over-the-air firmware update. DO NOT power off when this is happening.
White
Breathing
Cellular Off
If the LED is breathing white, the cellular connection has been turned off. If you did not explicitly turn off the cellular connection via the on-board switch, please notify QuantAQ.
Red
Blinking
System Failure
A system failure has occurred. This is likely caused by faulty on-board firmware or corrupted memory. Please contact QuantAQ for next steps.