Networked Weather Station (EE 4391 Group 2.3) Senior Design Project Team Dean Thomasson, Stephen Frank, & Nick Speir Sponsored by:

Networked Weather Station(EE 4391 Group 2.3)

Senior Design Project TeamDean Thomasson, Stephen Frank, & Nick Speir

Sponsored by:

Background Information (IoT)

Internet of Things (IoT):● The IoT allows us to network physical everyday objects with

embedded electronics and software to achieve a greater value and service through exchanging data and operation control.

● Freescale wants to become more familiar with how best to integrate their hardware into the IoT marketplace.

Design Details (Goals)

● Construct a weather station that communicates over a Thread (IEEE 802.15.4) network:○ Collect inputs from various weather sensors.○ Aggregate, package and transmit the collected values.○ Store the final data in a central database.

● The final design should focus on:○ Low energy (low power consumption) remote nodes.○ Small size and low cost.

● Final design reports to be submitted to Freescale to be used as reference design material or as application notes

Design Details (Stretch Goals)

● Display data from the database using analytical graphing software.

● Analyze the effects of loading the ZigBee network with a lot of sensors and traffic.

● Provide remote power source for the weather station (i.e. solar panels or batteries).

Design Details (Project Scope)

● Students: Responsible for the weather station itself, which includes reading in sensor values onto the Kinetis KW2x MCU radio board and then transmitting those values over the Thread network.

● Freescale: Responsible for configuring the Thread stack and central gateway router to request sensor data from the weather station and then pass along that data to Proximetry over the internet.

● Proximetry: Responsible for receiving the data from the central Thread gateway router, storing the data, and providing access to visualize the data via a Web User Interface (Web UI).

Design Details (Network Diagram)

Design Details (Hardware)

Minimum Accuracy/Resolution of Weather Sensors:● 1 kPa for pressure● 0.5 °C for temperature● 0.011 inches for rain fall● 1 MPH for wind speed● 22.5 degrees for wind direction● 10 μW/cm2 for irradiance


Temperature Sensor● −40 °C to +125 °C Range

Freescale Barometric Pressure Sensor● 50 to 115 kPa, Absolute

Wind Speed/Direction and Rain Sensor● Rain Gauge: Self-Tipping Bucket, 0.011 inch increments● Anemometer: Cup Type: 1.492 MPH = 1 pulse per second● Wind Vane: Eight resistance type sensors, 22.5° increments

Light Sensor● Contains both infrared and full spectrum diodes● Extremely wide dynamic range 1 to 600,000,000 Counts● Temperature range: -30 to 80 *C


Possible Future Upgrades● Better sensors such as a PAR (Photosynthetically Active

Radiation) sensor, which measures photosynthetic light levels in both air and water.

● Provide remote power source for the weather station (i.e. solar panels or batteries).


Freescale’s Kinetis KW2x MCU Radio Transmitter Board is programed to read in the sensors using Freescale’s Kinetis SDK and IAR

Design Details (Software)

The transmission of sensor values uses Thread, an IPv6 based protocol for “smart” home devices, which is built on top of the IEEE standard 802.15.4 for low rate WPAN.


The 802.15.4 standard defines the physical layer (PHY) and media access control (MAC) layer


The physical layer defines frequency, power, modulation, and other wireless conditions of the link.


The MAC layer defines the format of the data handling.


Thread provides enhancements to the network and transport layers such as authentication, encryption, and a data routing capabilities like the self-healing mesh network.


● Implementing Thread in our project:


The first thing that happens is the Thread gateway router sends out a request for sensor values.


Upon hearing the request the Transmitter board will read in the requested sensor values.


The transmitter board then responds to the Thread gateway router with the requested values.


The sensor values are then sent over the internet to the Proximetry database where they are stored.


Real-time weather station data can be accessed from any browser via Proximetry’s Web UI.

Design Details (Validation Testing)

● Individual Sensor Verification● Data Transmission Verification● Completed Design Verification

Bill of Material (Prototyping)

Freescale Parts:● Tower KL46Z Microprocessor Board $150● Tower Elevators $80● Tower Analog to Digital Converter Board $120● Kinetis KW2x MCU Radio Board $150● Tower Prototyping Board $15● Freescale Barometric Pressure Sensor $15

Total: $530Non-Freescale Parts:

● Wind Speed/Direction & Rain Sensor $70● Light Sensor $7● Temperature Sensor $2● Enclosure $50● Unistrut Mounting Frame $88

Total: $217

Bill of Material (Production)

Freescale Parts:● Kinetis KW2x MCU Radio Board $150● Freescale Barometric Pressure Sensor $15

Total: $165Non-Freescale Parts:

● Wind Speed/Direction & Rain Sensor $70● Light Sensor $7● Temperature Sensor $2● Enclosure $50

Total: $129

Budget Review

Freescale Budget for non-Freescale parts: $200Freescale Budget Spent to Date: $129

University Budget: UndefinedUniversity Budget Spent to date: $88

Manufacturability Issues

● Need for Custom connector○ A custom connector must be manufactured to connect the

weather sensors in the production model. This could increase production costs and lead times slightly.

● Translucent Material Needed○ The light sensor housing needs to be a highly transparent

material that doesn’t fog up or collect dirt easily.

● Automated assembly could be costly.

Societal Impact

● The Internet of Things (IoT) has the potential tochange the way we interact with the world around us.

● The networking protocol, Thread, is already being used by connected thermostats and other home automation applications.

● With all of these devices connected to the internet they are opened up to remote access and automation.

● This level of connectivity has the potential to greatly increase the usefulness and benefit that we normally receive from everyday devices.

Environmental Impact

● The weather station has a relatively low environmental impact.

● All of the materials used in its construction can be recycled by conventional means, such as with the plastic enclosure or metal mounting frame, or through an electronics recycling facility for silicon devices.

● Its low power consumption provides for efficient operational costs both economically and environmentally.

Ethical Responsibility

Security● To protect the security of data and intellectual property:

○ all documentation and software was accessed by machines which were password protected. Or if this was not possible (like on the Kinetis KW2x MCU radio board) it was kept locked up when not in use.

○ Access was limited to only those who were directly involved in the project.

Safety● Best practices for electrical safety were used when constructing

the weather station to ensure the safety of all those who may come in contact with it.

Summary

● The Networked Weather Station provides a means for remotely monitoring various weather sensors.

● This is accomplished via a Thread network using Freescale’s Kinetis KW2x MCU Radio Board and gateway router.

● Real-time data can be accessed from any browser via Proximetry’s Web UI.

● The production cost of a fully assembled weather station with

wireless transmitter is expected to be less than $300.

Documents

Networked Weather Station (EE 4391 Group 2.3) Senior Design Project Team Dean Thomasson, Stephen Frank, & Nick Speir Sponsored by: