Types of Data Collected > Auditory
Auditory sensors are very important to provide feedback and control for as they can be very small and easily occluded. It is important to know when we're being recorded in our homes because it is where we have some of our most private conversations. We tested prototypes of feedback and control for a voice controlled home automation system, a smart TV, and a smart security camera.
General Guidelines
Lights indicating volume are understandable, but may distract from the device.
Lights indicating volume that look like an equalizer display are very understandable indicators to users that audio is being recorded. However, they can be distracting to users and may be an unnecessarily loud form of feedback. Be sure to test for this before implementing this technique.
Lights as feedback on our TV prototype
Justification
As an equalizer is a design that is already utilized in other devices that have microphones, we thought this would be a good technique of providing feedback that audio is being recorded. We tested this technique on the TV and the security camera. In both cases, users understood what the feedback was trying to convey. On the TV, however, users found it to be distracting from actually watching TV. On the security camera, users described the feedback as being too "loud", especially if they wanted their camera to be more of a discreet recording device than a theft deterrent.
Feedback
Use audio feedback for any device that is controlled through speech.
Users expect a device that they give commands to via voice to talk or beep back at them, indicating that the device has heard them. This also allows the user to understand that the device is working without having to look at the device.
Audio feedback from the motor of a voice controlled device
Justification
One of our prototypes of the voice controlled home automation hub that we built had an anthropomorphic [link] component with motors that made inadvertent sounds when users started to issue a voice command. Users commented on the sound being helpful for them to be able to know when the device was recording their voice. We also found that when a user hears a device talk to them, it makes them think that they can talk back to the device. We observed this with some of our toilet and mirror prototypes that had verbal audio feedback.
Use small holes in the device to indicate that an audio sensor is present.
Little holes (as depicted in the picture) inform users that there is a microphone present and that there is a possibility of being recorded. This type of indicator is already used in devices like laptops and phones, so it will be easy for users to understand it in other connected devices.
Small holes to indicate microphone on a MacBook
Justification
When we tested the security camera without any indication of audio recording, many users did not assume that the security camera could record audio, as most CCTV cameras nowadays do not. However, some of them mentioned that they would think that it is recording audio if they saw a small set of holes on the device, like mentioned above. The relationship between seeing a pattern like this and thinking that a device is recording audio is so strong that participants thought that one of our door locks that had this pattern [IMAGE] was recording audio.
Provide subtle feedback that passive listening is occurring.
Many users that purchase a device with passive listening capabilities know that it will be listening all the time, unless they turn that function off or unplug the device. However, it is still important to provide feedback for this type of recording. Having some sort of subtle feedback, like a small, non intrusive light would let users know that the device is passively listening, without distracting them.
Light on a voice controlled device - use a subtler light than this to indicate passive listening.
Justification
One of the versions of our voice controlled home automation hub had a ring of light that was slowly fading on and off to indicate that it was passively listening. While some users found this feedback useful, many found it to be unnecessary, and even distracting in a case where a user said they would put this device in their bedroom. To be able to address both of these types of users we propose a small light that would not be bright enough to disturb someone in the bedroom, but that would still be noticeable when investigated up-close.
When using the pop-up technique on a camera with audio recording capabilities, turn on the light next to the camera after it pops up.
Make sure to turn on the light after the camera pops up, because, even if the light turns on as the camera pops up, it is impossible for a user to know if the light was on before the camera popped up.
Example of a light that may make the user think audio is being recorded all the time.
Justification
When we tested a version of the TV that had a light on when the camera popped up, a few participants mentioned that they were not sure about whether or not the TV was recording audio while the camera was not popped up. Several participants mentioned that if the light turned on a few seconds after it popped up, they would understand that it had not started recording audio until then.
Utilize the pop-up or pop-out technique to indicate that a device is recording audio.
The pop-up and pop-out techniques are extremely successful in allowing users to understand when a device is collecting audio information. One of the big advantages of these feedback methods is that it is very noticeable and unambiguous when it is applied.
Pop-up technique on a voice controlled device
Pop-out technique on a TV
Justification
In our tests of the techniques on the voice controlled device and TV, participants immediately understood what they meant. The movement, and noise that accompanied the movement brought the participants attention to the device. In addition, some participants found the movements in reaction to their commands "cute" because the device was giving a life-like reaction in response to their action.
Control
If the device passively listens, include a button on the device to turn off the passive listening.
Having a device passively listening in the home is still a very foreign concept to many users. Even if the device does not store any of the audio data it is passively listening to, users need to be able to stop the passive listening effortlessly.
Button on a voice controlled device
Justification
In our prototype testing sessions, many users expressed concern over a device passively collecting data. Having this control on the device allows them to choose whether or not it is collecting information, and gives a peace of mind to the user. Similar concerns were expressed when the media released the story that Samsung smart TVs were passively listening to conversations occurring at home.
 
Types of Data Collected > Visual
Visual sensors are particularly important to provide feedback and control for, as a lot of information can be found out about a person through sight, making it one of the most privacy-compromising modalities. We explored how people reacted to the collection of visual data with a smart security camera, a smart doorlock, a smart TV, and a smart mirror.
General Guidelines
Use a light to indicate that a visual sensor is recording.
The light should be near the visual sensor, and bright enough to be seen anywhere within the field of view of the camera.
LED to indicate that a visual sensor is recording
Justification
Staying aligned with existing practices by placing a light next to a visual sensor saves users from having to learn a new type of feedback, allowing them to understand the feedback more quickly. In many existing devices, a small light (usually red) is used to let the user know that they are being recorded. When testing our prototypes that did not have a light next to the camera, users were unsure as to whether or not the device was recording.
Only use visual sensors when absolutely necessary.
While video sensors can be very helpful in collecting a rich dataset, video sensors should only be used when the value provided by the device absolutely requires visual data. Video is a very sensitive data type for users and they will feel more private if the device could offer the same benefits without the use of video data.
Justification
This is an instance of a more general recommendation made by the FTC focusing on data minimization.One example of doing this would be to use NFC as a way to recognize who is coming up to a smartlock, rather than using facial recognition.
Feedback
Consider incorporating life-like features into feedback techniques to make the feedback more noticeable.
Giving an object life-like characteristics can help allow it to be more noticeable. Two anthropomorphic techniques that can be used for visual sensors are pop-up and swivel.
Pop-up technique on TV
Swivel technique on security
Justification
The pop-up technique was very noticeable and understandable on the TV as it allowed users to see when the lens was visible from far away because it broke the regular shape of the TV. We tested the swivel technique on the security camera, and while some users liked it, some found the feedback intrusive or unnecessary.
Make sure shutters are noticeable from the normal viewing distance of the device.
Different devices have varying distances for regular use, and the size of the shutter should increase as the normal viewing distance of the device increases. In addition, the sound of the shutter moving does not need to be quiet, as the sound can be a good auditory cue for the user to know that the shutter has opened or closed.
Shutter over a camera lens
Justification
Placing a shutter over a lens gives users additional peace of mind that the sensors are not recording them. With reports of cameras on TVs and laptops being hacked without the users knowing, the ability to cover the camera lens makes users more confident that no one is watching. Many people currently use sticky notes or other add-ons to block their laptop camera because they don't trust it to not be recording all the time. This solution builds the lens cover right into the device, reducing hassle for the user.
Consider using a screen that displays the video feed captured by a visual sensor when there is a user accessing that feed.
While TVs with a Skype application already let the user see what the person on the other end of the call sees, this method of feedback should be applied to other devices. For example, a smart lock with a camera on it should allow the person at the door to see what the homeowner sees.
Video feed on a smart door lock
Justification
Showing the person at the door what the homeowner sees helps in two ways. First, their privacy is not invaded, as it lets them know that they are being recorded. Second, it improves the functionality of the device as they know where they need to be if they do want to be seen.
Control
Don't only place the control on the device itself.
The devices with visual sensors we tested with (security camera, door lock, and TV) are usually interacted with from a distance. Because of this, it makes it harder for the user to control the sensing functions of the device if the only control is physically on the device. Consider putting the control in an application that can be accessed from the user's phone, or on a remote that comes with the device, in the case of a device like a TV.
Control on a remote
Justification
In addition, it is generally not advisable for devices like the security camera. doorlock, and other security-related devices to have a control on them, since a thief or other person may turn off the recording capability against the owner's will.
 
Types of Data Collected > Biometric
Biometric data is any type of data that collects information on human characteristics. We tested biometric data with a smart mirror, smart toilet, and smart bed. These devices collected data like blood sugar levels, pregnancy status, heart rate, skin quality, breathing rate, and sleep patterns. Many devices that collect biometric data are used in private spaces of the home. See our Private Spaces page for insights specific to the space that these devices live in.
General Guidelines
Be particularly considerate of privacy when designing devices that collect biometric data.
Since biometric data often focuses on human characteristics that aren't readily observable, it is information that many people do not even know about themselves. As such, many people may not feel comfortable with other people having access to this data. In addition, biometric information is generally collected in private spaces, like the bathroom and bedroom.
Justification
In our research, we found that we got the most extreme reactions to the feedback and control mechanisms implemented on devices that collect biometric information. In general, people see the data as a part of themselves and as such are more protective of that data. One consideration that came up multiple times in our research, but was not in our scope, is how to keep the information that these devices collect private from other people that might be using the same device or living in the same house as the initial user.
Feedback
Don't use verbal auditory feedback in most devices that collect biometric data.
Having a device talk makes users feel like the device is another person that they are talking to. Many people would not want another person talking to them in many of the contexts in which biometric devices live.
Justification
For example, users were especially creeped out when a toilet was talking to them, because it felt like someone else was in the bathroom with them, which made them feel very uncomfortable.
Use a screen to provide feedback where possible.
The types of information that these devices collect and the ways in which the devices collect the data are very complex. Using a screen with text to describe what the device is doing is very helpful in allowing the user to understand how it works. Screen-based interfaces also afford users the opportunity to explicitly consent to data collection.
Screen on a smart mirror
Justification
In our research with the mirror, toilet, and bed, we found that participants had a better understanding of what the devices were doing when they had a screen (either built-in, or on an application on a phone). The information we had on the screen told users what was happening at each stage of data collection, and showed them a read out of the information it collected.
Don't provide feedback that incorporates life-like characteristics.
Life-like characteristics (e.g., a physically moving part in a device) can make users feel like there is another being in the vicinity of the device.
Urine collection cup on a smart toilet
Camera flipping up on a smart mirror
Justification
This presence of another being in the vicinity of the device was met with apprehension in two of our tests. First, the urine collection cup on the toilet, which moved into the bowl and out of the bowl was described as "scary" and had very extreme reactions in general. Second, a lens that flipped up on the mirror was described as "unfriendly" and intrusive by some participants.
Control
Strongly consider letting users customize if and how a device will record their data.
Giving control of when a device collects data in the user's hands makes users more comfortable with the device. Giving the user an option of opting in each time they use a device is one technique of doing this. Another technique is putting a switch on the device that controls whether the device is recording.
Opt-in mechanism on a smart mirro
Switch on smart toilet
Justification
Although more research needs to be done to figure out which mechanism is the best for each device, we found that devices that collect biometric information need some way for users to communicate whether they want to be recorded or not. We studied the following mechanisms in our research:
Opt-in/opt-out: Having the device prompt the user to allow it to record each time they use it. This technique can be burdensome for the user and may be perceived as annoying for some, but other users see this interaction as a necessity.
On/off Switch: Having a switch on the device that allows the user to turn on or off the recording capability at any time. This technique does not interrupt the user's regular use of the device. However, some participants mentioned that they may accidentally leave the switch in the off position, and forget to turn it on when they want to use it.
Future Research ideas > Outside of feedback and control
Our research focused on feedback and control of connected devices. During our research, we came up with ideas that we did not have the bandwidth to prototype, and were outside the scope of feedback and control. We hope designers and researchers reading this will use this list as inspiration for future designs.
Batched Data
Giving users the ability to send data in batches (weekly, monthly, etc.). This way, users can remove the data that they do not want to send out before their data gets sent to the cloud.
Education
Educating users on the sensing properties of the device before they install it, either through videos, on the exterior packaging, or on transparent stickers on the device that point to the different sensors.
Dashboard
A dashboard that allows a homeowner to see all of the devices in their home, what type of data they are sensing, and the flow of data between devices and to the cloud.
Feedback and Control Mechanisms > Feedback
Feedback mechanisms allow users to understand when a device is recording data and when it is not. This page contains a list of general guidelines for incorporating different types of feedback mechanisms.
Lights
Consider that different colors of lights have different meanings.
In our research, we found that users perceived the colors below to be indicating the meaning written on the right.
Red: Recording, Error, Locked
Orange: Error
White: Recording, Powered On
Green: Unlocked, Powered On
Justification
In our tests of multiple devices, we asked participants to tell us what they thought each type of light feedback that we provided meant. The list above was aggregated from the responses we got for devices that had lights with the corresponding colors.
Don't use multiple light patterns with subtle differences on a device.
No more than one light pattern with a subtle difference from another should be used on a device as they are hard for users to remember and interpret. In addition, light patterns should be used as sparingly as possible, as they are not easily understood at a glance.
Multiple light patterns on a voice controlled device
Justification
We found that our feedback mechanism prototypes of the voice controlled home automation devices that had light patterns were much harder for participants to understand than those that did not use light patterns, and those that had one light pattern were easier to understand than those that had multiple.
Place lights close to the sensor that they are indicating feedback for.
When using a single light (e.g., an LED) for feedback, place it next to the sensor that it is providing feedback for. Many users associate the location of the light with the location of the sensor, even if this is not the case.
LED close to lens on smart TV
Justification
In our prototype of the mirror, we placed a light in a different location than where we had placed the lens of the device, and participants looked near the light for the sensor. We found a similar pattern of behavior when we placed a light on the bed to indicate sensing functionality as well. Participants tended to think that the location of the light was where the sensors were.
Use a subtle light as feedback that passive listening is occurring.
Most early adopters that purchase a device with passive listening capabilities know that it will be listening all the time, unless they turn that function off or unplug the device. Having some sort of subtle feedback, like a small, non-intrusive light would let users know that the device is passively listening without distracting them.
Light on a voice controlled device. Use a subtler light than this to indicate passive listening.
Justification
One of the versions of our voice controlled home automation hub had a ring of light that was slowly fading on and off to indicate that it was passively listening. While some users found this feedback useful, many found it to be unnecessary and even distracting in a case where a user said they would put this device in their bedroom. To be able to address both of these types of users we propose a small light that would not be bright enough to disturb someone in the bedroom, but that would still be noticeable when investigated up-close.
Only use subtle light feedback in the bedroom and on TVs.
A bright light in the bedroom can disturb someone that is sleeping. If a light is needed, subtle light feedback that will not disturb someone that is asleep can be used. On a TV, a lot of bright lights can distract from the TV screen. A small LED, or an indication on the screen can be used to indicate that a sensor is recording.
Lights as feedback on our TV prototype.
Justification
In our testing sessions with the bed, many people did not like our prototypes that used a light for feedback, as they said it would disturb them while they are sleeping. However, they did like our use of a click-button that they could press to turn on and turn off the recording capabilities of a bed, as they could feel the button to see if the bed is recording. One of our prototypes of the TV had six LEDs on it, to indicate that the device was recording audio data. Many users expressed that this would distract them from watching TV, and did not want so much feedback from one device.
Screens
Use screens to describe what the device is doing where possible, especially on complex devices.
Devices that involve a lot of steps or have complex sensing systems can benefit from having text to help the user along with the process of letting the device collect the information. Using a screen with text to describe what the device is doing is very helpful in allowing the user to understand how it works.
Screen on a smart mirror
Justification
In our research with the mirror, toilet, and bed, we found that participants better understood what the devices were doing when they had a screen (either built-in, or on an application on a phone). The information we had on the screen told users what was happening at each stage of data collection, and showed them a read out of the information it collected.
Auditory
Only use verbal auditory feedback if the device has voice recognition.
If a device talks to a user, many users will think that this means that they can talk back to the device.
Justification
As products like Google Now, Siri, and Cortana become more popular, people are starting to become comfortable with talking to their devices and having their devices talk to them. In particular, they expect to be able to talk to any device that talks to them. In our prototypes of the mirror that gave voice feedback, most users talked back to the device, even though we had not intended for the device to accept voice input.
Consider keeping the sounds of motors that are used for moving parts that are providing feedback.
The sounds that the motors make are useful because they bring attention to the device. They help increase the noticeability of feedback techniques. In addition, the device maker then does not have to create a separate sound for the device.
Audio feedback from the motor on a voice controlled device
Justification
The servo motors we used in many of our prototypes make a sound when they are run. We did not intend for this to happen, but many users felt that the sound of the motor brought more attention to the device.
Anthropomorphism
Don't use moving parts or verbal auditory feedback without explicit user input.
Don't use feedback that could make your device feel life-like on a device that needs to provide feedback to an implicit user input, like motion sensing. Having a device move or make a noise without the user telling it to do so can be startling for the user.
Camera flipping up on a smart mirror
Justification
When participants approached some of our prototypes of the mirror, a camera popped up or the mirror started talking to the participant. Many participants found these actions which were triggered without their explicit input to be "alerting", "unfriendly", and "startling".
Consider the costs and perceived risks that come with having a moving part.
Consider the costs for both in the manufacturing stage, and for consumers. Adding a moving part to a device can be costly, especially when mass-producing a device. In addition, many users perceive moving parts as another thing on a device that could break, and make the device cost more to them in the long run.
The intricacies and possible breaking points of a moving part
Justification
In our tests of the TV, mirror and toilet, many participants expressed concern over the prototypes with moving parts, stating that they could see them possibly breaking, and therefore creating an added cost and inconvenience for them.
Use anthropomorphism to make your device easier to understand.
Making your device more life-like or human-like can make it easier for users to understand. Using moving parts can communicate much more and be more noticeable than a light. Also, verbal auditory feedback can explain exactly what is happening to the user.
Lens popping up on a tv to increase understandability
Justification
Participants found that our prototypes of the TV, voice command device, mirror, and toilet that incorporated some form of anthropomorphism as feedback were easier to understand than the other versions.
Feedback and Control Mechanisms > Control
Control mechanisms allow users to decide when a device is recording data and when it is not. This page contains a list of general guidelines for incorporating control mechanisms.
General Guidelines
Make sure controls are easy to access.
Users need to be able to easily access the control for a device. Depending on the device, this may mean placing it on the device or on a remote control or mobile app.
Control on a remote
Justification
In our earlier testing sessions, many participants expressed that they would not want to approach devices like TVs or smart vacuums to turn off the recording capability of the device. They would rather turn off the recording capability from a remote control for the TV or from a mobile application for a smart vacuum.
Consider using a switch or a click button as a physical control
Users already have experience with these types of controls, therefore they are easy for users to learn. Consider using them on devices that users already have to be within arms reach to interact with.
Switch on smart toilet
Justification
Participants expressed that our prototypes of the toilet and bed that had these types of controls were relatively easy to use and understand. The convenience of having a physical switch will allow users to control devices without interrupting their normal interactions with the device.
Make sure it is easy to understand what sensor on the device the control manipulates.
The placement and design of a physical control can have a huge influence over what the user thinks it will manipulate. This can be accomplished by making sure that the control is close to the sensor that the device is manipulating and that it is close to the feedback for that sensor.
Light next to the control that controls the same sensor on a smart bed
Justification
One of our prototypes of the bed had the control and feedback for when the bed was collecting data in different places on the bed. Many users did not make the connection that the control was manipulating the same sensor that the feedback mechanism was providing feedback for. In our next iteration, we put the feedback and control next to each other and users were better able to understand that the control and the feedback were connected to the same sensor.
Things to Consider > Home Monitoring Devices
In our research with the smart security camera and door lock, we found that our participants were making comments on both that had a common thread, since they are both home home monitoring devices. Market research suggests that these devices are among the most popular of connected devices and are expected to usher in the widespread adoption of connected technologies. This page summarizes our findings on these devices.
Deter Intruders, Be Discrete, or Both?
Some Participants Wanted Very Obvious Device Feedback to Deter Intruders
A few of the participants that tested our prototypes of Home Monitoring Systems and Door Locks mentioned that they would want to have their security systems be as prominent as possible. This is because they want to deter intruders from even thinking of entering their home, because they would know they are being watched. This idea comes from the same school of thought in which people place signs for home security systems on their front lawn to deter potential intruders.
Some Participants Wanted Discreet Device Feedback to Record Intruders
Although a few of the participants wanted to deter the intruders, many of them wanted to discreetly record them. Some did not want intruders to know that there is a smart device there, but some were ok with them knowing it is there, as long as the intruders do not know where the sensor is on the device, or how to disable the device.
Can we Give Users the Option to Do Either?
We see two ways to address this split in attitudes towards the level of discreetness used in security devices. One would be creating a device that is inherently discreet, but can be customised with lights, sounds and moving parts to be more of a deterrent, up to the user's discretion. The second would be to create a device that strikes a balance between the two, allowing intruders to know that there is a device there that is recording them, but only up to the point that it would not make the device vulnerable to hacking, breaking, or any other kind of disabling.
Multiple Users and Use Cases
Three User Groups
There are three main user groups of home monitoring devices whose needs should be kept in mind when designing the devices.

Residents
Residents in a home need to be able to understand what is happening with all of their devices and be able to control them at all times.
Visitors
In order to keep their privacy concerns to a minimum, visitors to a home should be able to understand when they are being recorded, and where they can go to be out of the range of a sensor.
Intruders
We go into more detail on the considerations for intruders in the section above. In short, there are two schools of thought. One being that intruders should be deterred by home monitoring devices that provide very obvious feedback that they are recording, and the other being that intruders should be discreetly recorded.
Two Use Cases
Traditionally, door locks and security cameras have had one purpose: security. However, now, as connected devices, they have an added purpose of allowing the user to monitor what is going on in and around their home to make sure everything is ok. In this case the user is not necessarily using the device for security purposes, but more for surveillance. For example, people now use home monitoring systems to keep an eye on their pets, children, and other family members for safety and communication purposes, not security.
Area for Further Research: The Doorbell as a Control Mechanism
In most of our testing sessions, we tested our door locks as devices with motion sensors that activated when a user walked up to them. However, in a few of our sessions, we told users to press a doorbell next to the door, and then we activated the device. A few users thought that the doorbell was directly activating the doorlock, while a few other users thought that the doorbell was a regular doorbell, and that the resident of the home that the lock is on was activating the door lock from their smartphone. Overall, participants responded positively when the camera on the door lock was activated by the action of pressing the doorbell. This is in line a the theme in our research that privacy is protected when users explicitly activate the sensing functions of devices. This idea of a doorbell controlling smart locks, whether directly or indirectly is one that should be explored further.
Future Research ideas > Within feedback and control
Our research focused on noticeability, understandability and clarity of feedback and control in the context of the primary user and primary interaction that the user has with the device. During our research, many other questions came up that we did not have the bandwidth to research. We hope designers and researchers reading this will use this list as inspiration for future research.
Secondary Users
What happens when you introduce a secondary user like a roommate, spouse, sibling or child to the equation?
Tertiary Users
How do we help guests and other visitors to a home to understand when they are being recorded?
Glanceability
How do we make sure that feedback on the devices is noticeable even when it is not transitioning from one state to another?
Connectedness
How do we let users know which devices are talking to each other?
Customizability
What is the best way to allow users to customize their feedback and control mechanisms?
Physical design
How do we physically design these feedback and control mechanisms to be aesthetically pleasing and still useable in the context of each device?
Things to Consider > Private Spaces
In our research with the smart bed, smart toilet, and smart mirror, we found that participants were making comments on all of them that had a common thread, since they are all in private spaces of the home. The bedroom and bathroom are areas in the home in which we are at our most vulnerable. This page contains guidelines for designing feedback and control mechanisms in these spaces.
General Guidelines
Make feedback and control clear even when visibility might not be optimal for the user.
The bedroom and bathroom are places where people with nearsightedness may not wear their glasses or contacts. In addition, users often manipulate devices with little or no light in these spaces. Feedback and control should be large enough and clear enough to allow these users to understand their connected devices without full visual acuity.
Justification
In our testing sessions, a few participants brought up that they do not wear their glasses in bed, and would not be able to see one of our prototypes. In addition, designing devices to be clear for people that are nearsighted or farsighted will allow for better usability for users with clear vision as well.
Don't use audio feedback in private spaces.
Audio feedback should not be used in either the bedroom or bathroom, as it could wake up other people in the room or other parts of the house. In addition, audio feedback from a device that collects sensitive information could compromise users' privacy to other people in the home. If audio feedback is absolutely necessary, make sure there is an option to turn it off.
Justification
In a few of our prototypes of the bed, mirror, and toilet, we incorporated auditory feedback. Many users responded negatively to it, expressing that it would wake up or disturb other people in the house, especially a significant other in the bed. They also mentioned that they wouldn't want their sensitive information, such as information from a smart toilet, to be broadcast so that people outside the bathroom could hear. Verbal auditory feedback should definitely not be used, as having a device talk makes users feel like the device is another person that they are talking to. Many people would not want another person that they do not know talking to them in the bedroom or bathroom.
Don't provide feedback that incorporates life-like characteristics.
Life-like characteristics, like a physical movement can make users feel like there is another being in the vicinity of the device.
Urine collection cup on a smart toilet
Camera flipping up on a smart mirror
Justification
This presence of another being in the vicinity of the device was met with apprehension in two of our tests. First, the urine collection cup on the toilet, which moved into the bowl and out of the bowl was described as "scary", and had very extreme reactions in general. Second, a lens that flipped up on the mirror was described as "unfriendly", and intrusive by some participants.
Bedroom
Only use subtle light feedback, or use a tactile indicator of system status.
A bright light in the bedroom can disturb someone that is sleeping. If a light is needed, subtle light feedback that will not disturb someone that is asleep can be used. In addition, consider using a physical indicator that can allow a user to feel a surface or a switch to understand if a device is recording. For example, a latch button can physically communicate its state through tactile means.
Switch on smart toilet
Justification
In our testing sessions with the bed, many people did not like our prototypes that used a light for feedback, as they said it would disturb them while they are sleeping. However, they did like our use of a click-button that they could press to turn on and turn off the recording capabilities of a bed, as they could feel the button to see if the bed is recording.
Consider that many devices in the bedroom are used by the same people every day.
As opposed to other devices in the home, the same person uses a bed most of the time. Because of this, subtler controls and feedback can be incorporated, as they need to be learned by a lower number of people.
Justification
In our research, we found that devices with a narrow range of users (e.g., usually the same few people sleep on a bed) need less obvious forms of feedback compared to devices that are interacted with a more diverse set of users. For devices with more consistent users, it may be best to explore how to educate users on how the device works at a different touch point such as at the point of purchase or during the installation process.
Bathroom
Consider that while the same people use the bathroom every day, there are times when guests use it.
While the same people use bathrooms most of the time, in general, they do have a higher chance of being used by guests. Because of this, it should be easy for the user to hide or make private any data that is collected by these devices that they may not want guests to see.
Justification
In many of our testing sessions with the toilet, people voiced their concern about guests, or other people in the home having access to their data if it was visible on a screen next to the toilet.