CSM Dust Sampler

Acknowledgements

Project Advisor: Lisa Woodward

EPA Technical Advisors: Mike Hoppe, Michelle Kerr, and Ray Ledbetter

CDPHE Technical Advisor: Alex Hedgepath

Elevator Pitch

Dust pollution is a growing problem for human health and the environment in many regions, and of increased social concern if it is thought to have come from a location with identified pollution problems.

Historically, organizations like the EPA have used particulate monitoring equipment, such as the DataRAM4, to determine whether the concentration of dust in the air was hazardous. However, these devices are limited to measuring dust concentration and offer little in the ways of determining the source and severity of this pollution. In some cases, equipment like the DataRAM4, has been discontinued, making maintenance on these aging units increasingly difficult.

The need exists for a device that can not only measure the concentration of dust in the air, but also help pinpoint its source and determine its severity.

Enter the CSM Dust Sampler.

The CSM Dust Sampler measures the concentration of airborne dust using its onboard PM2.5 sensor, and can help determine its source from wind speed and direction measurements from its built in anemometer and wind vane. These measurements are recorded in a spreadsheet stored on an external USB drive for easy access to the data after monitoring has concluded. The truly innovative feature of the CSM Dust Sampler is its ability to collect and store up to eight dust samples for later lab analysis; an incredibly useful feature when determining the long term severity of dust pollution.

The device you see today is the first prototype of the CSM Dust Sampler, and the first step towards realizing the full potential of this device.

Design Approach

Design Solution

The culmination of six months of work can be seen in the final CAD model of the CSM Dust Sampler (pictured at left in Figure 4). The original goal of the team was to present a working and tested prototype in time for the Senior Design Showcase, but, unfortunately, the advent of COVID-19 prevented the team from meeting in person and dispersed them around the state and country. Unable to access the necessary materials, tools, and facilities, all physical development of the prototype stopped, which, consequently, prevented testing. To overcome these setbacks, the team focused their efforts on creating virtual models, diagrams, and flow charts to illustrate the extent of their progress prior to the virus.

Operation
The process of collecting dust samples is explained in the steps below (please also reference Figure 5):

1. Outside air is drawn through the intake at the top of the device. This intake is omnidirectional so that the rate of dust collection isn’t affected by wind direction or device orientation.
2. The air then passes through a filter that collects the dust particles before being exhausted from the device through the fan.
3. After a predetermined amount of time, the fan stops running and the flap that holds the filter rotates 90 downwards.
4. Vibration motors positioned filter-flap assembly shake the collected dust off the filter, where it is then funneled into one of empty vials below.
5. The filter-flap rotates back to its initial position, and the vial racking system rotates the next empty vial into position under the funnel. With the exception of the opening for the funnel, the vials and the vial racking system are completely separated from the rest of the device by an acrylic sheet, which helps protect the integrity of the samples once collected.
6. The fan starts back up to once again draw air through the device, and the process begins again. While the device is collecting dust, an array of sensors gather data on dust concentration, wind speed, and wind direction to better help determine the source and severity of the samples.
7. Once started, the device can run without user intervention, collecting up to eight dust samples and storing all sensor data on a removable USB drive.

Electrical

The wiring diagram for the CSM Dust Sampler can be seen below in Figure 6. Most of the components present in the diagram are low power consumers, which is important when one considers that the dust sampler must operate off of battery power for days at a time. The exception to this is the fan, which, as Table 4 illustrates, consumes as much as 27.6W and accounts for approximately 95% of the CSM Dust Sampler’s power demands. The team had initially selected a 0.6W fan (in large part due to its low power demands) but found that it could not generate sufficient airflow through the filter. The team then opted to purchase the most powerful fan compatible with the system, with the intention of being able to scale back the fan’s power (through PWM) as needed. Unfortunately, COVID-19 disrupted the team before the fan could be tested.

As Table 4 illustrates, operating the dust sampler at max power becomes impractical to supply with batteries after more than a few days. This illustrates the need to reduce the power of the fan as much as possible, as well as the need to provide supplementary power (e.g. solar panels – a 50W panel is typically $60-$120).

Program

The program behind the operation of the CSM Dust Sampler is illustrated in the flowcharts of found in Figure 7 and Figure 9. Although COVID-19 prevented an assembled prototype for which to test the program, the isolated operation of each component (i.e. motors and sensors) was successfully verified beforehand.

Budget

The project was initially constrained by a slim budget of $500.00, but a detailed BOM and proposal were able to convince the Project Advisor to increase the budget to $1,000.00. Even with the larger budget, the team still practiced money saving techniques, such as reusing materials when possible, using the Maker Society’s free-and-reduced 3D printing, and comparing the prices of similar products before purchasing. Since COVID-19 halted development of the prototype, some planned purchases were never realized, which is why the team came in $662.35 under budget, having spent a total of $337.65 on materials for the prototype.

Benefits and Broader Impacts

Dust pollution is a growing problem for human health and the environment in many regions, and of increased social concern if it is thought to have come from a location with identified pollution problems. Innovative tools, like the CSM Dust Sampler, will prove to be huge assets when determining the severity and source of dust pollution; necessary measurements when it comes to protecting public health and assigning responsibility.

Next Steps

To finish the project to where the team had expected to be, the following steps need to be taken:

• Order the remaining components and create the custom components
• Assemble the prototype
• Test and troubleshoot the prototype’s program
• Test a variety of filter types with the prototype and determine a suitable type
• Evaluate the overall performance of the prototype

To improve upon the team’s work and elevate the CSM Dust Sampler from a prototype to a fully realized design, the following will need to be completed:

• Determine exactly what contaminants will be collected and apply any design changes necessary to the vial racking system.
• Optimize power consumption by decreasing component power consumption (such as that of the fan) and adding power generation (such as solar panels).
• Procure high end materials that are likely to be used in industry.
• Determine the cost of a device made of these materials.
• Improve the portability and durability of the device
• Create a housing system that allows for this device to be operated by a single user

When these next steps are taken, a truly effective product (not unlike the one the team envisioned early on in the design process – see below) can be delivered to the client and to additional customers.

Meet the Team