The Qulet. Quantifying Residential Electricity Consumption BREE-495 [BREE-495] Hyunjoong Kim, Kai Park, Dr. Clark April 14, 2015

Transcription

1 The Qulet Quantifying Residential Electricity Consumption BREE-495 Hyunjoong Kim, Kai Park, Dr. Clark April 14, 2015 [1]

2 Contents Executive Summary [3] 1. Introduction [4] 2. Design Concept Review [4] 2.1 Design Problem [4] 2.2 Design Goals [4] 2.3 Design Constraints [5] 2.4 Proposed Concept [5] 3. Prototype Development [6] 3.1 Components [6] Microcontroller [7] Relay [7] Current Sensor [8] Manual Switch [9] AC to DC Converter [9] Wi-Fi Board [10] 3.2 Circuit Layout [11] 3.3 Wiring [13] 3.4 Programming [14] 4. Testing [15] 5. Analysis [18] 6. Optimization [21] 6.1 Optimizations Achieved [21] 6.2 Limitations [21] 6.3 Future Optimizations [21] 7. Possible Future Directions [22] 7.1 Communication with Base Unit [22] X10 [23] Insteon [23] Zigbee [23] Z-wave [23] Thread [23] 7.2 Predictive Capabilities & Synergy [24] 7.3 Product Standards [24] 8. Conclusion [24] 8.1 Challenges [24] 8.2 Conclusion [25] Acknowledgements [25] References [26] Appendix A [28] Appendix B [29] Appendix C [33] Appendix D [35] Appendix E [36] [2]

3 Executive Summary This report entails the development and building of the Qulet, an integrated electricity measuring outlet. Typically, a consumer is unaware of how much energy the house is consuming until the end of the month, when the consumer receives the utility bill. This can make saving energy difficult, as a monthly bill is inefficient. Also, the unit of the kwh is not well understood by many consumers. The Qulet aims to solve this problem, and give users more control over their electricity usage. The Qulet measures a consumer s electricity consumption, and displays the data in real time in terms of currency. This will help consumers track their energy consumption habits, and help encourage energy saving habits. The device will also have a wireless control capabilities, allowing the user to turn the out let on or off remotely. The Qulet is made out of five primary components: a microcontroller, current sensors, a relay, a voltage converter, and a Wi-Fi board. These components work in conjunction together as a system in order to give the Qulet its abilities. Continuing off from the initial design proposal, the project underwent vigorous developing according to the final four stages of the design cycle: analysis and specification, prototyping, optimization, and testing, in order to build the best prototype possible. The results from the testing stage were analyzed, and the prototype was deemed successful. The Qulet worked according to majority of the specifications, and the primary functions that were initially set out for the Qulet to have were achieved. The total cost to build the Qulet prototype was roughly $100. However, if put into production, the parts would be outsourced and the final cost to purchase the Qulet will be cheaper. The report then analyzes the possible future directions of the Qulet, especially with respects to the home automation market. [3]

4 1. Introduction In Canada, household energy demands cost roughly $26.8 billion. As reported by Behidj et al., 17 percent of energy demands in Canada are due to the residential energy sector, with energy demands from this sector continuing to increase. From the year 1999 to 2009, there was an increase of 11% in energy consumed in household. With an increasing population, it is clear that residential energy requirement will increase over time. 38 percent of the residential energy consumption is powered by electricity. Due to Canada s cold climate, a significant portion of the energy is used for heating space and heating water (Statistics Canada, 2012) with the two consuming 63 percent and 17 percent respectively. Following that, 14 percent is consumed by appliances. In the last decade, there have been many developments in home automation to decrease the overall amount of electricity consumed. Consumers are often unaware of their monthly electricity usage, and are even more unaware of the monthly costs until they receive their electricity bill at the end of the month. This method can make it difficult for users to cut down on energy, and reduce their energy consumption. Furthermore, the unit of the kwh is often not well understood to most consumers. As a result, they may be unaware of the scale of how much energy they are consuming and be more wasteful. As a solution, quantifying the kwh and presenting a consumer s real time electricity consumption in terms of dollars may help incentivize energy savings through the reduction on energy bills. Using a microprocessor and a variety of sensors, we have designed an electrical outlet that measures the power consumption of an appliance, and communicates this data to the user. 2. Design Concept Review 2.1 Design Problem In most households, electricity usage is shown by monthly electricity bills. The metering device in each household records the consumption of electrical energy in kilowatt hours (kwh) and is converted to an amount payable to utility companies in dollars per kilowatt hour ($/kwh). This design makes it challenging for consumers to reduce their electrical usage. The monthly measurements shown on the bill are the cumulative values of consumption and do not detail or differentiate the location or uses of the energy consumption. This also means that consumers cannot examine their real-time consumption and cannot effectively compare their recent and previous consumption patterns. Furthermore, the unit in which the energy consumption is expressed (kwh), is not fully grasped by many consumers. This leads to ill-informed and wasteful energy consumption. Expressing real time electrical energy consumption and quantifying the kwh in terms of dollars may help facilitate and motivate energy savings. 2.2 Goals The fundamental goal of this design is to reduce energy consumption in residential households by bringing awareness of electricity consumption directly to the consumers. The clients would become [4]

5 conscious of their consumption through up-to-date, real-time information, as well as through associating the consumption with the expected billed equivalent. This information and awareness would also provide the clients the incentive and the control to alter their consumption habits by saving money. 2.3 Constraints The design of the measuring device must satisfy certain physical, safety, and practical constraints for it to be successful. Electrical circuitry and utility systems differ across continental regions. The measuring device targeting Canadian residential households must consider outlets that are wired using three wires: a hot wire, neutral wire, and ground wire, and that supply 120 V of alternating current (VAC). A typical European outlet, however, would be wired with two wires: a hot wire and a neutral wire, and would deliver 230 VAC. For this design to be effectively used, it must be compatible with retrofitting into current household designs. This requires easy and safe installation measures to be considered. Since there is a risk of electric shocks, a failure mode must be implemented. At the first sign of danger, the failure mode would be activated, and would potentially prevent any serious damages or fatal accidents. Safety is a crucial aspect of all designs, and our design will be no different. Finally, the device needs to be practical and draw the least amount of power possible. The function of the device requires it to be continuously active to send and receive signals, and to constantly measure electrical energy consumption. This will cost the client a small amount to operate. For this design to be a viable option for consumers, the power drawn from the grid must be kept to a minimum. 2.4 Proposed Concept Our design, the Qulet (a combination of the words Quantifying Outlet ) is a concept that redesigns the outlet in an effort to determine the energy consumption of appliances. This usage would be determined by a design that consists of sensors that measure the current of that electrical outlet. The usage data would then be expressed on a displaying interface for the client to see. Ultimately, this would satisfy our objective of providing higher resolution of electrical energy consumption, given that all outlets have been updated to this design. The Qulet is an integrated outlet, and would look like any other normal outlet and be flushed with the wall, as pictured in figure 1. [5]

6 3. Prototype Development 3.1 Components Figure 1. The Qulet installed in a bedroom, flushed with the wall like a normal outlet In order to construct our prototype designed in the initial design proposal, components must be carefully selected based off of the minimum requirements needed for each part. There are five main components to our design: a microcontroller, an electrical relay, a current sensor, a manual switch, and an AC to DC converter. Although not part of our initial design, a Wi-Fi board was added to our final design, in order to add wireless capabilities and wireless control. It is important to note that the components that were selected and purchased are not representative of the final product. Due to the limitations in resources, our prototype was built using components available on the market; however, if the product reaches the production stage, the necessary parts will likely be outsourced. This will allow for needless features of the component bought to be excluded, and focus only on the necessary parts and design components specific to our needs. Furthermore, it will minimize costs, meet production demands, and be made as small as possible. A full list of the materials, as well as the total cost that was required to build the prototype, can be found in table 1 below. Table 1. A list of materials used in the prototype, as well as its costs. Part Cost ($) Arduino Uno Voltage Converter Relay Shield ACS712 Current Sensor (x2) 7.95 (x2) CC3000 Wi-Fi Board Total [6]

7 3.1.1 Microcontroller Based off of our design, the microcontroller must meet the following criteria: Have at least 7 digital inputs Have at least 2 analog inputs Perform Mathematical Operations Clock Generator The Arduino UNO R3 possesses an ATmega328 microcontroller, with 14 digital input/output pins and 6 analog inputs (fig. 2), which is more than what is required for this project. The board connects to the computer using a USB connection, and can be powered by either the USB or an external power source. If powering through an external power source, the input voltage must be between 7-12 VDC. The USB connection will be particularly useful for our purposes, as it provides for easy transfer of data that is collected to the computer Relay Figure 2. Arduino Uno Microcontroller (Source: Simply put, a relay is an electrically operated switch. This component allows for the ability to turn the outlet on or off remotely. Different from a mechanical switch, the relay responds to instructions from the microcontroller, which determines the state of the relay. Standard household circuit breakers are rated at 15A and provide a voltage of 120VAC. Therefore, the relay must be able to handle at least 15A of current and have a voltage capacity of 120VAC. Also, the relay must be compatible with the Arduino. The part purchased is an Arduino relay shield (fig 3), which allows for it to be placed on top of the Arduino board, which saves space and makes the wiring more organized. The relay is rated at 10A and a maximum voltage rating of 250 VAC. Although it exceeds the voltage requirements needed, the current rating is insufficient. However, these ratings are an indication of how much power (in watts) can be switched through that relay, rather than the limitations of voltage can current. So, for the relay purchased relay, a total of 2,500 watts (250VAC x 10A = 2,500 watts) can be passed through without damaging the component. We deemed this to be sufficient enough for our prototype, and that precautions would be taken in order to keep the power passing through below its rating. Although it was possible to purchase a relay that would meet the requirements of the amperage, we decided that the benefits of having a less cluttered board with less wiring was more beneficial. [7]

8 It is important to note that the relay shield has two relays that are capable of being controlled, however, the prototype only uses one. In our initial design, we required two relays, with the second relay being a safety relay which switches off in case of an emergency. However, we realized that all capabilities were able to be done with one relay, we were able to optimize our prototype by reducing the number of relays and saving space. Figure 3. Arduino relay shield. (Source: Current Sensor The current sensor is an essential part to the prototype, as it is needed in order to perform the power calculations. The requirements of the current sensor needed are that that it must be able to read currents up to 15A of 120VAC, and be compatible with the Arduino. The current sensor chosen is an ACS 712 Hall-effect based current sensor, as seen in figure 4a. The current sensor has the ability to measure up to 30A of current. However, this current sensor module was not the initial sensor chosen for the prototype. The ACS 712 is an invasive sensor, meaning that the wires with the current flowing through must be physically wired to the sensor. Our initial design report indicated that a non-invasive current sensor was desired, due to the fact that an invasive sensor may be a potential point for failure, if not wired correctly. With a noninvasive sensor, the wire with the current flowing through would just have to pass through the sensor s whole, without and direct wiring, as seen in figure 4b. Unfortunately, during the testing phase with the non-invasive sensor, the sensor was not returning correct values, and there was a problem with the sensor. We were unsure if it was due to the quality of the part or if we did not code correctly, but the values did not seem correct. As a result, we switched sensors to the ACS712 sensor. [8]

9 (a) 30A ACS712 Current Sensor (b) A non-invasive current sensor (Source: Figure 4. The current sensors used for the prototype Manual Switch The purpose of the manual switch is to give the user the ability to manual turn the outlet on or off. Our prototype uses a switch similar to the one in figure 5 below. Figure 5. A manual switch (Source: AC to DC Converter An AC to DC converter is needed in order to convert the AC output from the wires to a lower voltage DC output to power the Arduino. More specifically, the voltage converter must convert a 120VAC input to a DC output, between the range of 7 to 12 volts. The reason why the Arduino capable of accepting a range of voltages is because it has a voltage regulator, which will decrease the initial voltage input to the voltage it requires. There was a wide variety of component that were able to be chosen from, and that fit the requirements mentions above. Therefore, we chose what was the least expensive. The part we purchased outputs 12 volts of DC current, and can be seen in figure 6. [9]

10 Figure 6. An AC to DC converter used for the Qulet. (Source: Wi-Fi Board As a last minute addition in order to optimize the Qulet, a Wi-Fi board was not a part of the initial design proposal. However, after coming across a series of Arduino projects that used a Wi-Fi board, we recognized that it was a necessary addition in order to fully demonstrate and validate our proof of concept. Initially, choosing the correct Wi-Fi board was difficult, as there are several options on the market and we were unsure of what was needed from the Wi-Fi board. Furthermore, we were unsure of the programming required in order for the Wi-Fi board to be functional. The component chosen, the CC3000, is a wireless network processor that incorporates internet connectivity to the Arduino. It uses SPI (Serial Peripheral Interface), a serial communication interface used for short distance communication, and it can be used with many security modes, such as WEP, WPA/WPA2, AES and TKIP. The CC3000 Wi-Fi board was chosen over other alternatives by exploring several Arduino projects that used a Wi-Fi board, and comparing the projects to ours. The project that was the most similar to ours used the CC3000 Wi-Fi board, so we made our decision based off of the likeness of our projects. Fortunately, in terms of coding, the project also provided the sample code for the Wi-Fi board, so we were able to use that code as a base and modify it according to our needs. Figure 7 shows the CC3000 Wi-FI board used for the Qulet. Figure 7. CC3000 Wi-Fi Board (Source: [10]

11 3.2 Circuit Layout In developing the Qulet s circuit layout, we wanted to minimize the number of parts in the circuit in order to save space and make the layout as simple as possible. This will not only simplify the project, it will also reduce the cost it build as we have minimized the number of necessary components. From the initial inception of the project, the circuit was carefully designed and critically examined at every step to ensure that the circuit was a simple as possible. After each review, we made the changes to the circuit to come up with the circuit shown in figure 8, which was presented in our initial design report. The initial proposed design has a live wire that is split into two parallel branches, with one branch leading to the voltage converter and and one branch wired to the relay. The electricity in the first branch is first converted from 120 VAC to 12 VDC, which will be used to power the Arduino. The Arduino will then be able to supply power to the relay, current sensor, and Wi-Fi board, as well as have the ability to send and receive data. The second branch is used to power the outlet, with the current sensor and relay a part of this branch. A manual override switch was placed before the live wire splits into branch to allow for the user to turn off the Qulet manually, and to also stop the Arduino from using power while the Qulet is off. The switch can also be place on just the branch leading to the Qulet, which would leave the Arduino running. However, the Arduino would still consume power and cost the user money, which does not make sense, economically speaking. For the relay, it was assumed that the outlet will be delivering power to the appliance for most of the time, so the relay was wired in the normally closed positon, which requires no power to complete the circuit and keep the Qulet running. Figure 8. Initial proposed circuit layout After initially proposing the circuit layout above, we re-examined the layout and made two key changes. Firstly, we were able to reduce the number of relays from 2 to 1, after we realized that one relay is sufficient for carrying out all of the tasks needed involving relays. The safety relay, which was initially [11]

12 meant to shut off in case of a discrepancy between the current flowing in and out of the outlet, can be removed as the relay that controls the outlet can also handle this task. Secondly, after we agreed to integrate a Wi-Fi board for wireless control and communication, we needed to integrate the Wi-Fi board into our circuit. The Wi-Fi board would not connect to the wires from the grid directly, and would only come into contact with the Arduino. A schematic of the new layout can be seen below in figure 9. Figure 9. Final prototype circuit layout Due to fact that out prototype is in its initial stages, and it is far from being put into production, we are unable to physically integrate our design into the wall and connect it to the wire from the circuit breaker. In order to test our circuit, the male end of an extension cord was wired to the Qulet, in order to deliver electricity from the circuit. When wiring the male end of the extension cord, careful attention was made to ensure that it was wire correctly, with respects to the prongs. The smaller prong delivers is attached to the hot wire, and delivers electricity to the system, while the larger prong is connected to the neutral wire, and delivers electricity back to the grid. The differences between the prong sizes, and to visually show which prong is the hot and neutral wire is show in figure 10. Figure 10. The small and large prongs on the male end of an electrical plug. (Source: [12]

13 The final, built prototype can be seen in figure 11 below. 3.3 Wiring Figure 11. The final prototype A schematic of the wiring between the Arduino and the relay, current sensor, and Wi-Fi board is shown in figure 12 below. A table listing the wiring and connections can be seen in appendix A. Figure 12. Schematic of the wiring between the Arduino and the relay, current sensor, and Wi-Fi board. [13]

14 3.4 Programming The code for the Arduino was written using the Arduino Software, which is a software specifically for writing, compiling, and uploading code for the Arduino. The Arduino can be programmed using the programming language specific to Arduino, and it is capable of being programmed in C and C++ programming language. However, due to our lack of knowledge in C and C++, the Arduino programming language was used. In the code, five libraries need to be imported in order to make the Qulet functional. Libraries add extra functionality to the Arduino by programming the Arduino to be able to do specific tasks that may be otherwise too complicated to write. Table 2 is a list of libraries that are imported in the code with a description of their function. The code to call the libraries in the program is below: // Import required libraries #include <Adafruit_CC3000.h> #include <SPI.h> #include <CC3000_MDNS.h> #include <arest.h> #include <Time.h> Table 2. Libraries imported to the Arduino for the project Library Adafruit_CC3000.h SPI.h CC3000_MDNS.h arest.h Time.h Description Library specifically used with the CC3000 Wi-Fi board. Allows for the board to be function with the Arduino and connect to Wi-Fi. Allows for the communication of data between two devices over short distances Sets up the Arduino on the local Wi-Fi network, and make it accessible by giving it local address, rather than using an IP address. Simplifies the Wi-Fi communication and allows for the sending of data and control of the Arduino using the web browser, as opposed to changing the code. Allows for the Arduino to keep track of and count time. Next, the variables within the code need to be defined, so that they can be assigned a value and called when needed. This is done by the following line of code. The initial voltage associated with the Qulet is 120V, and is defined by the variable effective_voltage. If used in a location where there is a 240VAC supply, the user must redefine the variable to 240. // Define measurement variables float current; float rms_current; float effective_voltage = 120 float effective_power; [14]

15 float zero_sensor; float calibrate; float sensor_value; After, the analog and digital pins were defined according to their functions and what is plugged in. The pin numbers were defined according to the way it the Arduino was wired in section 3.3, and can be seen appendix A. Another important line of code is defining the network the Arduino should connect to. These values should be user inputted, and the user must enter the Wi-Fi s network name, password, and security type within the code, in order to connect to the network. The user can input the information in the underlined portion of the code, as shown below. // WiFi SSID and password #define WLAN_SSID " " #define WLAN_PASS " " #define WLAN_SECURITY Lastly, another important lines of code is the code to execute the calculation required for power measurement. In this portion of the code, the user must input the cost of electricity per kwh. This value can be inputted by filling in the blank in the Cost variable, as shows below. The full code can be found in Appendix B. 4. Testing calibrate = sensor_value-490; current = (float)(calibrate)/1024* ; rms_current = abs (current/1.414); effective_power = abs(rms_current*effective_voltage); float power = effective_power; float kwh = power*now()/ ; float Cost = kwh* ; Once our program was written and ready to be uploaded, we were ready to test our prototype. We tested our prototype in a systematic manner, starting with the general functions of the Qulet such as if the power is being delivered to the appliance, to the more specific functions such as if the wireless control feature is working. The first step in testing out prototype was to verify the wiring. Before uploading our code and testing the functionality of the outlet, we had the wiring verified by Xuebin s father, who is an electrical engineer, to ensure that the physical model was safe to be used. Also Xuebin verified the wiring between the Arduino and the relay, current sensor, and Wi-Fi board, to ensure that we had wired it correctly. [15]

16 Next, we tested to see if the circuit delivered power to all components. Before we plugged in the Qulet in to the wall outlet, we first plugged in a lamp into the outlet on the prototype, so that a live current was not passing through the Qulet when we plugged in the appliance. Because there is a small amount of exposed wiring, this was done for safety purposes so there was minimal risk of being electrocuted. A lamp was chosen as the appliance, because we can visually verify if power is being delivered or not. With the manual switch in the on state, we plugged the male component of the Qulet in the wall circuit, and the lamp turned on (fig 13). Furthermore, the LED lights on the Arduino and the other components also lit up. This proved that the system was delivering power to all of the components correctly. Figure 13. Powering a lamp using the Qulet to test if it was wired correctly and electricity is being delivered. We turned the manual switch on and off, to test the manual switch component (fig. 14). The lamp turned on and off in response the manual switch. Next, the functionality of the relay was tested. This was done by uploading a simple code on to the Arduino, telling the relay to turn on and off every 5 seconds. The relay responded to the code, and turned the lamp on and off in 5 second intervals. This showed that the relay connection correct and that the relay was functioning properly. Figure 14. Manual Switch on the Qulet The current sensors were tested to see if they were wired correctly and to test their functionality. We tested this in a similar manner to the relay (by uploading a basic line of code), but instead of verifying if the lamp turned on or not, the serial monitor was opened, which displays the data in the Arduino [16]

17 programming interface. As mentioned previously, when we tested out the non-invasive current sensors, our values were not correct, and no documentation was found online that would help us make sense of the results. Therefore, the Qulet initially failed to move past testing the current sensor. But after replacing the non-invasive current sensors with the ACS712 (fig. 15), the readings that were being displayed were more constant, and it was verified by the documentation found on line. The documentation stated that with no current flowing through, an initial sensor value between 480 and 512 would be displayed. The current sensor, displayed a value of 490, which falls within the range in the documentation. Figure 15. ACS712 current sensor, integrated into the Qulet. Finally, the code that was written was verified by using the verifier function in the Arduino programing interface, and it was uploaded to the Arduino. The code uploaded without a problem, and when the code was run, the serial monitor confirmed that the Arduino was connected to the internet by displaying an IP address in the serial monitor. To test if the Qulet was correctly measuring electricity consumption, a hair dryer was used as the test appliance. Due to the quality of the current sensor, currents of less than 1A were unable to be detected by the sensor. Therefore, to produce results for analysis, an appliance with a heating element, such as a hair dryer, was used as they generally have higher power requirements. The hair dryer was allowed to run for roughly 4 minutes while the Qulet was recording the data. Values such as current (A), power (W), energy consumption (kwh), and cost ($) were displayed on the serial monitor, and the data was then imported to Excel for further analysis. Figure 16 shows the final testing stage of the prototype, with the hairdryer plugged in. One flaw with our design is that the current output displayed is not constant, and fluctuates. This is due to the fact that AC current is not constant, and changes direction of its flow by 180 over a time interval, which is graphically represented by a sinusoidal wave. AC current is usually measured by calculating its root mean square value (RMS) of its peak current value. This is where the flaw lies, we were unable to accurately detect its peaks in order to calculate the RMS value. [17]

18 Figure 16. The final prototype with the hair dryer plugged in for testing In order to test the wireless control of the Qulet over Wi-Fi, the following web address was entered in a web browser on a device that was connected to the same network: The address searches for a device named arduino.local on the Wi-Fi network, and sends data, telling it to turn the digital pin number 7 on. The digital pin only understands binary, so the on state is defined as 1. Due to the fact that the relay is wired in a normally closed configuration, when the relay is on, the electricity delivered to the outlet is cut. After entering the address in the web browser, the lamp turned off, verifying that the wireless control works. If we want to turn the relay off (thereby deliver power back to the outlet), a similar web address is used, except the relay would be defined as 0 (off), as seen below. 5. Analysis Once the data was displayed in the serial monitor of the Arduino, the data was transferred to an Excel spread sheet, and the data was graphed. The variables that were graphs are the current, power, electricity consumption, and cost. As mentioned in the testing section (section 4) of the paper, the values of the current fluctuated between its peak, 12A, and zero (as seen in figure 17). The current, especially from t= 113s to t = 199s, shows a repeating pattern of current measurements, which suggests that the Qulet is correctly sensing the current drawn by the hair dryer. Another way to validate and confirm that the Qulet is functioning properly with respects to its electricity measurements, is to compare the power rating of the hair dryer and the data. The hair dryer is rated at 100 VAC and 1200 watts when it is on its highest power mode. From this, we can calculate the maximum current rating of the hair dryer by doing a simple power calculation (eq. 1): Power = Current Voltage (1) 1200 watts = Current 100 V Current = 12 Amps [18]

19 Power (Watts) Current (Amps) [BREE-495] With the maximum current rating at 12 amps. This confirms that the Qulet is correctly measuring the current, and that the issue with the inconsistency is caused by the inability to constantly read the peaks Current vs Time Time (s) Figure 17. Graph of the current measured vs time. From the current measurement, the power measurement can be calculated, simply by multiplying the current values by the voltage. Figure 18 displays a graph of the power drawn by the hair dryer. It is important to note that the maximum power displayed by the graph is at 1400 watts. This is higher than the rating of 1200 watts given by the hairdryer. This discrepancy is due to the fact that a constant value of 120V was assumed to calculate the power, as opposed to the 100V rated by the dryer. Normally, the voltage can range from 100V to 120V, depending on the appliance. Ideally, the voltage should be measured as well, however, as a simplification, 120 volts was assumed Power vs Time Time (s) Figure 18. Graph of the power measurement vs time. [19]

20 Cost ($) Electricty Conumption (kwh) [BREE-495] Electricity Consumption vs Time Time (s) Figure 19. Graph of the electricity consumption vs time. The next value to be calculated is the kwh, which is the measurement the utility companies use in order to quantify a consumer s energy consumption. A kilowatt-hour can be calculated simply by multiplying the power, in kilowatts (kw), by the amount of time the appliance is drawing power (in hours) (eq. 2). Although it is difficult to directly validate this parameter, a general upward trend of the energy consumption (in kwh) can be seen over time, which is what was expected (fig. 19). Energy (kwh) = Power (W) Time (hr) 1000 (2) Lastly, arguably the most important parameter to be measured, is the cost of running the appliance. The cost of running the appliance can be calculated by the following equation (eq. 3): Cost = Energy Consumption (kwh) Electricity Rate ($) (3) The electricity rate is the price of energy per kwh, and varies depending on the price charged by the utility company. The cost also shows a general increasing trend over increasing time (fig. 20), which is expected, as the longer a consumer uses and appliance, they more they will be charged Cost vs Time Time (s) Figure 20. Graph of the cost vs time. [20]

21 6. Optimization 6.1 Optimization Achieved As mentioned in section of the paper, the prototype initially consisted of two relays. One for the user to have control over, and the second one to provide a safety feature that would automatically shut down the circuit in case of large current differential between the input and the output. However, the two functions were effectively coordinated with one relay, not requiring the second relay. This creates more space in the electrical box as seen in Figure 21, allowing for additional integration of components if needed. Another optimization was done by integrating a Wi-Fi board in the circuit as discussed previously in section With this addition, it provided the prototype with a greater capability in terms of control power with the use of the internet. Under the same Wi-Fi connection, the user has complete control over Qulet via a smart phone, tablet or a computer. 6.2 Limitations Figure 21. Front and Isometric Views in AutoCAD In the process of optimization, there were a few limitations with the prototype and the code. Since the current sensor that was used to measure the Hall Effect was a low quality sensor, it was incredibly difficult to calibrate and consequently led to difficulty in obtaining constant RMS values. Also, note that a constant voltage value across the circuit was assumed to be 120V, where in reality, this simplification does not hold. The biggest limitation, however, is the fluctuating current output by the current sensor, as discussed in section 4. This can potentially be corrected by increasing the sampling rate, and changing the code so that the Arduino only detects the peaks and outputs them. 6.3 Future Optimizations There are few optimizations that can be made further in order to improve the current prototype and address the limitations. Improvements in the code would greatly reduce the data discrepancy that was seen in the analysis section. For example, replacing the current sensor with a better current sensor and [21]

22 coupling it with higher sampling rate would allow accurate data logging. Also, developing data acquisition system from Arduino to Matlab or similar programs to analyze the data in real-time would be a step in the right direction. An alternative method to this is to send the data directly to a server to be stored, analyzed and accessed at any time. 7. Future Development Our project focuses primarily on the hardware and programming component of the outlet, and to ensure that it has the capability to provide the user with data representing their respective electricity consumption in real time and express the data in units of currency. However, despite the capabilities to perform these tasks, the outlet itself is not a smart device in itself. The Qulet is only a small part of an overall bigger system that will give user total control over the Qulet s functionalities. Ideally, the Qulet would communicate with the base unit, which will receive and aggregate the data from multiple Qulets. The base unit, which would be connected to the internet via an Ethernet connection or Wi-Fi, would send data to a server in order to store that information. The user, who will have to have an external account set up, will be able to access their consumption data through the server using a phone app, Computer Program, or signing in into a website. Figure 22 shows the overall system of how the Qulet would connect to the server. 7.1 Communication with Base Unit Figure 22. System Operation After further development and rigorous testing to finalize the Qulet, the next step would be to build the base unit. The primary function of the base unit is to communicate with the Qulet, and relay information between the server and each individual Qulet. A list of communication protocols considered can be seen in table 3: Table 3. A list of communication protocols suitable for the Qulet. Protocol Communication Method X10 Power-Line Insteon Power-Line Zigbee Wireless Z-wave Wireless Thread Wireless [22]

23 One requirement of the protocol chosen is that the protocol must have the capability of communicating using a mesh network. Mesh networks allow for less traffic of information and a faster response and less dropped commands/signals. Due to the high number of outlets and amount of data being collected by the base, a mesh network is essential. Using Thread is an extremely interesting choice as a protocol. Although it is relatively new, it was designed by google and is what Nest uses to communicate. Using the Thread protocol can allow for communication with Nest, allowing for a simpler controls of multiple devices, as well as the potential for the outlets to synergies with Nest to become Smart X10 X10 is a communication protocol that uses power line for both signal and control. It involves the use of short bursts of radio frequencies to pass on digital information. The data is passed on to devices with X10 protocol during the zero crossings between the sinusoidal alternating current waves Insteon Insteon is a communication protocol that is very similar to X10. It uses both power line and radio frequency to exchange data from each device. The advantage of using Insteon over X10 is that, it provides wireless, more reliable data transmission in context of error detection and correction Zigbee Zigbee is a wireless communication protocol that is intended for applications related to monitoring and controlling. It uses a mesh network to process to pass on data. The advantage of this protocol is that, it can be easily integrated in to a microprocessor, such as Arduino and that it has a relatively quick response time. However, because of its shorter range compared with Z-wave, it is not suitable for home automation applications Z-wave Z-wave is a wireless communication protocol that was designed specifically for home automation and a few other commercial applications. It uses MHz as a frequency band, which has the advantage of not interfering with Wi-Fi or Bluetooth Thread Thread communication protocol is one of the most recent protocols that was developed. It is used by companies such as Google, Samsung, Silicon Labs and a few more. Thread uses 6LoWPAN, which stands for internet protocol version 6 (IPv6) over Lower power Wireless Personal Area Networks. It is designed for various applications such as house appliances, energy management, lighting, safety and security. It has many advantages over previously discussed protocols including low interference, low latency, selfcorrection and more. The protocol itself is a larger scope and will not be discussed in this report any further. [23]

24 7.2 Predictive Capabilities & Synergy The use of an algorithm and the data acquired by the sensors can be developed in order to predict and learn the user s habits and create a schedule. For example, Nest Sense uses sensors and an algorithm in order to sense if the user is home, actually using the heating, and predicting user behaviour. Furthermore, Big Ass Fans, a smart ceiling fan company, claims to use an algorithm and a predictive learning microprocessor in order to build a schedule. However, information on what algorithms are used and how the algorithms were developed was not able to be found, likely due to protect their respective research from other companies and competitors. Although developing a unique algorithm would be ideal, and it is purely conceptual. When developing the algorithm, the basic parameters that would be taken into account are the following: Motion/temperature detection When the outlet was last programmed Time of day Recent activity/when the last outlet was last used Another feature the Qulet can potentially have is the predictive and learning capabilities dependent on another automation system. The Qulet would receive data from another smart appliance, and use their schedule in order to match the user s needs. This method would require the user to have a another home automation appliance in their home in order to maximize the full capability of the outlet, 7.3 Product Standards The most important aspect of product development other than functionality is the health and safety of the user. Under the electrical regulations of Canadian Standards Association (CSA), the implementation of one or more failure modes such as a manual override is necessary along with documentation of the product as well as the description/function of the safety feature is needed. See Appendix C for CSA general requirements regarding safety functions incorporating electronic technology. 8. Conclusion 8.1 Challenges The main challenge we faced as a team was the fact that we were two students with a background Bioresource Engineering, which is completely different than electrical engineering. Having little knowledge of electronics and circuits created uncertainty and hesitation in the preliminary stages of the design cycle. This was overcome when the prototype was finally put together in working order. Time constraint was another challenge that we had not foreseen. The parts arrived 6 weeks after it was purchased, leaving us with limited time. This made our Gantt chart extremely difficult to follow and we had to make considerable amount of adjustments and changes to our project timeline in order to fit every task within the given time constraint. Refer to Appendix D for detailed Gantt chart. [24]

25 8.2 Conclusion In conclusion, the project was completed successfully by addressing the primary goal of providing electrical power consumption, while respecting the constraints of engineering design safety. Although Qulet was able to measure power consumption on an appliance specific level with variability in data, it was able to clearly show the proof of concept of the design as well as the wireless connection via the internet. The final prototype consisted of two current sensors, a microcontroller, a mechanical relay, AC to DC voltage converter and a Wi-Fi board. Further optimization such as data acquisition and code improvement can be done to increase the accuracy and reliability of the product. For future direction, systems design that include the base unit as well as a communication protocol between the individual Qulet units with the base unit needs to be developed. Thread as a communication protocol is recommended for its fast and secure data communication, however, the method of integrating this communication protocol is kept classified. Acknowledgements We would like to acknowledge Dr. Clark and Dr. Lefsrud for their help and direction of this project and for their continuous support and encouragement. We would also like to thank Xuebin Tian for his technical help and guidance. [25]

26 References Allegro MicroSystems Inc ACS712: Fully Integrated, Hall-Effect-Based Linear Current Sensor. Available at Accessed April Alexander, Charles K., and Matt N.O. Sadiku Fundamentals of Electric Circuits. 4th ed. New York, NY: McGraw Hill. All About Circuits Power Factor.: All About Circuits. Available at Accessed November 25, Belkin WeMo Insight Switch. Playa Vista, CA. :Belkin. Available at Accessed on 11 November, CSA C22.2 No Safety functions incorporating electronic technology. Available at Accessed on 2 April, 2015 Efergy Engage Online Energy Monitor. Darnall, United Kingdom.: Efergy. Available at Accessed on 11 November Energy Efficiency Trends in Canada 1990 to 2009, Chapter 3, Residential Sector, Behidj N., Brugger M., et al., December 2011, Natural Resources Canada, Available at: oee.nrcan.gc.ca/publications/statistics/trends11/pdf/trends.pdf Energy use in Canada Canadian Geographic. Available at: Accessed 28 November Hydro-Québec Next-Generation Smart Meters. Montréal, QC.: Hydro-Québec. Available at Accessed on 10 November MH Residential Wiring Guide. 11th ed. Winnipeg, MB.: Manitoba Hydro. Available at Accessed on 15 October, 2014 MH Standby Power. Winnipeg, MB.: Manitoba Hydro. Available at Accessed on 13 November, Nest Life With Next Thermostat. Palo Alto, CA.: Nest. Available at Accessed on 11 November, 2014 NRC Standby Power When Off Means On. Ottawa, ON.: Natural Resources Canada s Office of Energy Efficiency. Available at Accessed on 13 November, [26]

27 OMOE Smart Meters and Time-of-Use Prices. Toronto, On.: Ontario Ministry of Energy. Available at Accessed on 10 November P3 International. Kill A Watt. New York, NY.: P3 International. Available at Accessed on 11 November, Rashid, Muhammad H Power Electronics Handbook - Devices, Circuits, and Applications. 3rd ed. Oxford, United Kingdom: Elsevier. Schwartz, Marco Arduino WiFi Power Switch & Energy Monitoring Device. Open Home Automation. Available at Accessed 14 April, Storr, Wayne Full Wave Rectifier. Basic Electronics Tutorials. Available at Accessed 25 November, TED How TED Works. Charleston, SC.: The Energy Detective. Available at Accessed on 11 November Threadgroup Introduction to Thread. Available at Accessed on April 14, 2015 Water heaters, last modified Oct 2014, Natural Resources Canada, Available at: Accessed 28 November 2014 [27]

28 Appendix A Arduino Wiring and Pin Definition Current Sensor 1 Current Sensor 2 Relay Current sensor Pin GND Vo 5V Arduino Pin GND A0 5V Current sensor Pin GND Vo 5V Arduino Pin GND A1 5V Relay Pin GND Vo 7 5V 5V Arduino Pin GND CC3000 Wi-Fi Board CC3000 Wi-Fi Board Pin GND Arduino Pin GND VCC 5V 3.3V 3V3 MOSI 11 MISO 12 CS 10 INT 3 SCK 13 EN 5 [28]

29 Appendix B Arduino Code // Code for BREE-595 Design: Qulet project // Import required libraries #include <Adafruit_CC3000.h> #include <SPI.h> #include <CC3000_MDNS.h> #include <arest.h> #include <Time.h> // Relay state const int relay_pin = 7; // Define measurement variables float current; float rms_current; float effective_voltage = 120; // Set voltage to 240V (Europe) or 120V (US) float effective_power; float zero_sensor; float calibrate; float sensor_value; // Wi-Fi Board Pins #define ADAFRUIT_CC3000_IRQ 3 #define ADAFRUIT_CC3000_VBAT 5 #define ADAFRUIT_CC3000_CS 10 // Create CC3000 instance Adafruit_CC3000 cc3000 = Adafruit_CC3000(ADAFRUIT_CC3000_CS, ADAFRUIT_CC3000_IRQ, ADAFRUIT_CC3000_VBAT, SPI_CLOCK_DIV2); // Create arest instance arest rest = arest(); // WiFi SSID and password #define WLAN_SSID " " #define WLAN_PASS " " #define WLAN_SECURITY // The port to listen for incoming TCP connections #define LISTEN_PORT 80 // Server instance [29]

30 Adafruit_CC3000_Server restserver(listen_port); // DNS responder instance MDNSResponder mdns; // Variables to be exposed to the API int power; void setup(void) { // Start Serial Serial.begin(9600); // Init variables and expose them to REST API rest.variable("power",&power); // Set relay pin to output pinmode(relay_pin,output); // Calibrate sensor with null current delay (50); zero_sensor = analogread (0); // Give name and ID to device rest.set_id("001"); rest.set_name("qulet"); // Set up CC3000 and get connected to the wireless network. if (!cc3000.begin()) { while(1); } if (!cc3000.connecttoap(wlan_ssid, WLAN_PASS, WLAN_SECURITY)) { while(1); } while (!cc3000.checkdhcp()) { delay(100); } // Start multicast DNS responder if (!mdns.begin("arduino", cc3000)) { [30]