ContextualInquiry:Power Ranger
From IEOR 170 Spring 2007
Contents |
[edit] Group Members and Responsibilities
Sumeet Patel
Responsible for problem solution overview, functionality summary, one interview and paper compilation
Shwan Kazzaz
Responsible for one interview, design overview and all sketches
Joshua Funamura
Responsible for one interview and task analysis questions
Fenelia Kosasih
Responsible for writing the analysis of approach
[edit] Target Users
When selecting our target users for the interviews we wanted a wide range of electricity users. We wanted to interview students as well as adults because we know that energy usage for different age groups can be different. In addition, we wanted to make sure we had some variation in gender to see if males and females differed in their power usage.
[edit] Interviewee 1
The first interviewee was a female college student, living in small apartment with one roommate. She is moderately concerned with environmental issues, but mostly concerned about cost. Her apartment is small, so there are extra appliances: mainly basic kitchen appliances, a small TV, lights, and computers. She is somewhat computer savvy.
[edit] Interviewee 2
The second interviewee was a male college student, living in a large house with ten roommates. The house has 9 bedrooms, 2 bathrooms, a kitchen, living room and basement. The house he lives in, is poorly insulated and contains four refrigerators. Also each of his roommates has mini fridges, computers and lamps in their rooms. The house contains laundry facilities, a big screen television and kitchen appliances. He was computer savvy with knowledge of wireless technology.
[edit] Interviewee 3
This user was a 61 year-old man. He is the head of a household, which houses his wife and daughter. He owns a 4 bedroom, 3 bath home in Marin County, CA. He watches a lot of TV on his 50-inch plasma screen, and he works from home in his home office, mostly on his desktop computer.
[edit] Problem and Solution Overview
[edit] Problem
The problem we are trying to solve is beneficial to both the environment and energy users. Most households do not watch their power consumption very closely and so energy levels increase and cause blackouts and energy shortages. Many energy consumers do not know why their power usage and bills fluctuate from month to month. Consumers have no way of knowing which of their products makes up the majority of their energy bills and so do not know what appliances to turn off.
[edit] Solution
Our proposed solution is to create devices, which can attach to each of the consumers outlets and report the amount of energy being used. We propose a solution where our device would plug into the wall outlet and than an appliance would be plugged into our device. Within our device an watt meter would detect the amount of energy flowing through and using wi-fi technology would send the information to a computer. This computer would be able to update real time data of energy use and present the consumption levels in easy to read graphs and figures.
[edit] Functionality
Once a user has installed the system, they will be able to monitor their power usage in real time. By being able to monitor the current months power usage they will be able to shut off power wasting appliances and save themselves money as well as the environment. A user will be able to compare previous months power consumption by appliance in easy to read graphs and figures. The software will also allow for a predicted energy usage for the month from previous months and years. All of these functions will allow for the user to be more aware of their power usage and actions taken after that will be up to the user.
[edit] Contextual Inquiry - Interview Descriptions
The interviews taken were all taken at the respective houses of each of the interviewees. We decided upon a certain set of interview questions that we must ask each interviewee but allowed ourselves to ask follow-up questions on answers given. This tactic was implemented because of the wide range of situations that our interviewees could have with their power consumption.
[edit] Questions Asked
1. How do you pay your power bill? Paper/electronic? Can you show me?
2. Do check your power usage levels during the month? Can you show me how? If not, do you ever wonder how much your are using mid-month?
3. Do you notice when one bill is higher/lower than the last?
4. Do you know how much you currently pay?
5. How does that relate to how much you would like to be paying/think is realistic?
6. Have you ever put any thought into which appliance in your home uses the most power? If so, which one?
7. Do you tend to leave appliances or power-using devices on while not around to use them? For example, lights in an empty room? If so, does it bother you that you do that?
8. Do you feel that it is necessary to watch your power usage levels?
9. Do you think you use significantly more power on given months than on other months?
10. Do you have housemates/roommates who use appliances that drain a significant amount of power?
11. Have you ever considered splitting the power bill? If so, how would you split it?
12. How do you decide what light bulbs/appliances to purchase? Does power consumption make a difference in your decisions?
[edit] Results
[edit] Interviewee 1
She used her computer to pay her electricity bills online but did not know if her power bills were higher or lower from month to month. Interviewee had no idea how much power each appliance was using or checked how much power she was consuming during that month. She would want to save power because of the cost savings and complained of roommates leaving lights and appliances on. When purchasing products, she did not look for how much energy was used but more of the upfront costs.
[edit] Interviewee 2
The second interviewee lived in a large house and received his bill in the mail but paid his bill online through his bank account. He did know the difference in monthly energy bills but didn’t know why his monthly bill fluctuated. The bills he received only told him how many kilowatts were used a month. He knew that during the winter months his power bill was higher due to the use of heaters. The interviewee complained about roommates using lots of power and having no way of telling who was spending more power. When purchasing products, energy consumption was not considered. The interviewee said no one living in the house thought too much about power because they split their bill ten ways.
[edit] Interviewee 3
From this interview, I was able to discern that the user pays his power bill by mail. He views a paper statement monthly and sends a check in the mail to PG&E. He noted that he is conscious of his power use and attempts to limit use around the house, but with 3 people it’s hard to make sure that no power is ever used negligently. He also noted that he actively tries to reduce his power bill, but does not know how much each appliance uses and wishes there was a way to tell. He believes his power bill is too high, but does not know how to approach fixing it. He also knows there are months where his usage levels vary and he does not know why (not winter, not vacation, etc., just more usage).
[edit] Task Analysis Questions
1. Who is going to use system?
• The typical users would be homeowners and apartment renters who pay their own energy costs and would benefit from conscious consumption decrease. Environmentally conscious occupants would use the system to be more informed about ecological impact of their living habits. Users will need to be literate, but generally not need to understand electricity past the basics. Since our system will be computer-based, they will need to own a computer and be able to operate it. Mobility is not so much an issue, except for in the case of installation, where many units might need to be deployed around a house. Usually older people are more concerned about energy consumption, but children might be potential users if the system can be made into a game.
2. What tasks do they now perform?
• They go online to receive their power bill and pay it.
• From the power bill, they may or may not look at their power consumption and the per-kWh cost.
3. What tasks are desired?
• We want users to see a history of their monthly electricity
• We want users to be able to see a breakdown of their monthly usage to weeks/days/hours or show real-time usage.
• The information will be in terms of the appropriate units (kWh, kW, etc) and in terms of monetary cost.
• We also want to break down the total usage into per-outlet or per-appliance usage, in the same array of time increments as previously mentioned.
• We want the user to be able to see which rooms/outlets/appliances are consuming the most power.
• We want the user to access predictions about how high the electricity bill will be in any given month.
• We want the user to be alerted when certain notification criteria are met, like the estimated electricity cost has surpassed a threshold.
4. How are the tasks learned?
• Initial installation is done by following written directions given with the product.
• Repeated tasks are presented in the user interface and can be learned on the fly or through a tutorial.
5. Where are the tasks performed?
• Installation, done once by the user, takes place around the house at different outlets.
• Repeated tasks are done at the home computer of the user during leisure time and generally not under stress or in a loud environment.
6. What’s the relationship between user & data?
• The data is specific to the user and to the location of installation, but isn't really sensitive.
• The information could be accessed remotely if desired, but generally isn't warranted.
7. What other tools does the customer have?
• The customers will have cell phones, PDAs, and the computer. They all could be used to deliver alerts for reaching specified cost/consumption thresholds.
8. How do customers communicate with each other?
• Not too relevant since systems in houses would be independent from one another
9. How often are the tasks performed?
• Basic tasks like checking overall consumption are normally performed monthly.
• With our solution, we can make tasks like checking current consumption be performed more often, whenever the user is interested in the amount or cost of the energy they are consuming.
10. What are the time constraints on the tasks?
• The tasks generally need to take as little time as possible. For many users who never monitor their energy usage, the tasks should be short as to not lose their attention. For users who normally manually follow their energy consumption, more complicated tasks can take longer time. In general, though, the feedback needs to be immediate and dynamic in order to capture the attention of the user.
11. What happens when things go wrong?
• In the event of units getting disconnected, power outages, or computer failure, the system needs a backup to the information gathered.
• The user interface is an independent program from the information, so the interface can always be restarted.
[edit] Analysis of Tasks
[edit] Easy
• A user can log onto their computer and can see the total energy consumption for the current month in real time.
• A user can compare the current months total energy consumption with previous energy consumption using graphs, monetary value and kilowatts used
[edit] Medium
• A user can see the energy consumption of each appliance for the current month in real time.
• A user can see compare the energy consumption for each appliance from current months to previous months using graphs, monetary value and kilowatts used.
[edit] Difficult
• A user can predict the current month or future month’s energy costs based on previous months energy use.
• The user must install each device on each desired outlet and set up the wireless receiver on their computers. The user must then setup the software and name each of the outlet devices by appliance.
[edit] Proposed Solution Design
The solution design is both a hardware and software solution. The hardware is noted in figures 1.1 and 1.2, both from the last Group Proposal submission. The hardware includes transmitters, shown in figure 1.1 placed around a room, and in figure 1.2 in more detail, that plug into a wall socket, and allow appliances to be plugged into them.
Figure 1.1
Figure 1.2
The simple design of each transmitter allows them to be manufactured cheaply and can enable a user to purchase many of them. Each transmitter then transmits a wireless signal to the base station receiver near a computer. The receiver feeds this data to the computer via the USB port. The software is a user-friendly interface that is the real value of the product.
Figure 2.1 shows the main screen users will encounter upon startup. This screen shows how much power each item that is plugged into a transmitter has used. This can be evaluated based on how much it is currently using, how much power it has used totaled over the last month, day, year, etc., or how much money you have spent at whatever rate you pay for power (entered by user). From this screen, users can gain much of the information that they really need and use it as a launching pad to further detailed information. Each bar graph is clickable to give further data on each appliance, including a graph of how much power has been used over a given period of time, as well as some statistics on power usage for that device (Figure 2.2). Furthermore, a user can then compare the graph to previous months (Figure 2.3).
Figure 2.1
Figure 2.2
Figure 2.3
Figure 3.1 depicts an example of an easy task that the software can be used to perform: checking the month’s energy consumption total. This can be done by clicking on the “View” menu, and then selecting “Monthly Consumption” from the menu. A “Monthly Consumption” window then appears showing the total energy consumption for the month, as well as the total price at a given rate, to be entered at setup by the user.
Figures 3.1 and 3.2
Figure 3.2 depicts an example of a moderate task that the software can be used to perform: checking how much energy has been consumed by each appliance. This is made very easy to do by our software, though it will be the main screen upon opening the software, if at any time, the user has moved to a different window and wishes to return to the “Bar Graphs” which break down usage for each appliance the procedure is not complicated. One first clicks the “View” menu, and then one selects “Bar Graphs” from the menu. The bar graph screen will appear, showing how much power each appliance is using, or has used for a selectable amount of time. One can also order the appliances alphabetically or by greatest consumption.
Figure 3.3 depicts and example of a moderate difficult task that the software can be used to perform: predicting monthly energy costs. It is expected that not every appliance in the house will have a monitor attached to it. However, the software will be able to make an educated evaluation of how much power these unaccounted for appliances are using. One first clicks the “View” menu, then one selects the “Power Bill” option from the menu. A screen with show asking how much the last power bill’s actual price was. The computer will also verify the power price rate per kwh. Lastly, it will ask you to evaluate how much you are using your unmonitored appliances in comparison with the last month. This is expected to be mostly the same as the previous month, as it will be recommended that those items which vary greatly in consumption from month to month are monitored by the system. Regardless, after entering how much the unmonitored devices have been used compared to the last month, either using a percentage system or a ranking system, the software will calculated how much to add to the current value it has calculated for the bill from the monitored appliances. This calculation is of course done using the total kwh consumption by the house and the power rate ($/kwh).
Figure 3.3
The software undergoes a simple installation, as any other computer software is installed, and the hardware installation will be streamlined as well. The main goal is to make the transmitters cheap, so that many can be purchased. The wireless communication with the base station will be entirely automated, so most of the hardware installation will simply involve plugging appliances, transmitters and the base station into either wall sockets or the computer. One the installation is complete, and the software is installed, one enters some information about their power consumption, such as their price per kwh, and their consumption from previous months. Any surcharges, taxes, and fees will also be noted for accurate bill estimation.
[edit] Analysis of Approach
One of the most important considerations in the design of the power-consumption monitoring device is the ease of installation. Existing device such as “ElectrisaveTM” may require the need to consult help from qualified technicians. However, our design uses a more intuitive approach of installation – just plug in the transmitter/sensor into the power socket at which the application is to be plugged into. No consultation with qualified technicians is necessary.
After multiple sensors have been plugged into the desired sockets, the receiver can be connected to a computer via a USB connection. The receiver receives signals from each transmitter every few seconds and sends the data to the computer. Software is installed on the computer, which will then generate the power consumption data of each appliance connected to the sensors. The power consumption data is given in both energy units and in dollar value (according to the electricity cost per hour that the user inputs).
Another existing technology, such as Kill-A-WattTM also has easy installation (just plugging into the socket and the LCD monitor will display the power consumption in energy units as well as in dollar amount.) However, such devices only read the power consumption for a single appliance, and multiple of such devices are needed for multiple appliances. Furthermore, compilation of the energy consumption data for each individual appliance must be done manually.
ElectrisaveTM on the other hand, gives the total power consumption, without the breakdown of the consumption of each individual appliance. This might be difficult for users to determine which appliances take up the most power, and which appliance should they reduce use on.
One downside to our design is the need to use a computer in order to monitor the electricity usage. Existing technologies made use of LCD screens on the receiver to display the electricity consumption data. Such designs are more persuasive, such that users can view the electric consumption easily. Our design, on the other hand, requires the user to turn on the computer first in order to monitor the electric usage. In addition, this design might not appeal to users who are not familiar with computers.
Links to existing technologies cited:
Kill-A-WattTM: http://www.p3international.com/products/special/P4400/P4400-HG.html
ElectrisaveTM: http://www.smarterproducts.co.uk/acatalog/Electrisave-Electricity-Monitor.html
