HMI PRINCIPLES
Smoke detector Redesign
/01
Overview
2019

Smoke Alarms (Ionization), not to be confused with Fire Alarms (Photoelectric), demonstrate a poor application of four key Human Machine Interaction (HMI) principles. These violations present an opportunity to redesign this common household technology so that it better suits its users.
Many of the violations identified affected the user’s ability to fully extend or utilize a variety of their senses: Visual, Auditory, Tactile and Haptic, as well as Cognitive senses.

The
four main violations identified in the exsisting alarm product are outlined below:
After identifying some common causes for false alarms, users were asked how they disarmed or silenced the product in 
that given scenario–responses ranged from opening a window to unplugging it, or in one case accidentally breaking the device while trying to reset it.
What do these false alarms mean?

120,378 dispatched calls in 2018 (Baltimore County FD)
6.83% of which were false alarms
Each dispatch costs, on average, $1,580, meaning…

$12,987,600*
was spent on false alarms in 2018




Statistics provided by
Derrick Ready, Deputy Chief Fire Marshal at BCFD
*Estimated*
There’s an area for oppurtunity–

The faults in the way the alarm functions causes
two major problems that need to be solved:

1. False alarms–these alarms are often disarmed franticly by the user; if done incorrectly (removing batteries, unplugging wiring), it could ultimately lead to the system not functioning when it needs to most, leading to a dangerous and potetially life-threatening situation.  

2. Loss of time, resources, and revenue for local fire depts.

NFPA 74 was updated and required smoke alarms to be present in all new home construction
History of Smoke Alarms.” My Smoke Alarm Fire Safety, www.mysmokealarm.org/history-of-smoke-alarms/
NFPA *National Fire Protection Association
1989
1993
1995

10-year battery-powered smoke alarms were invented

NFPA 72 first required that smoke alarms be placed in all bedrooms
The Common Household Smoke | Fire Alarm
HMI Principles
False Alarms and Their Causes
Task Analysis
Visual

Signal detection theory provides a precise graphical 
notation for users to analyze decision making in the presence of danger or uncertainty.
Users aren’t aware of what the warning means. Is it a fire? Steam from the shower? Bacon on the stove?
Placement of them(alarms) being high up and far away delivers minimal sense of notice.
Auditory

False alarms are common, they can be extremely loud and can cause stress for users.

Residential alarms sound at an average of approx 75-95 db. In general, sounds above 85 db can be harmful to adults and sounds above 70 db can be harmful to infants.

According to
Patterson’s (1990) Criteria for Alarms, alarms should never be overly startling or abrupt.
Labeling

Labels on the alarm have no contrast with the surface and can be hard to read or distinguish.
The label that differentiates between an ionization (smoke) alarm or a photoelectric (fire) alarm is located on the back of the device–facing against the ceiling. This information is important to let the user know what kind of alarm gets placed in which areas of a living space.
Height

Alarms are always placed high and near the ceilings because smoke | heat rises.

Because of this placement, users often have to use a ladder, chair, stool or other platform device to reach it.

Users may try to unplug or damage the system in an attempt to silence or disarm it.
/02
Research
User Surveys, Expert Interviews, User Statement
Dialogue Flow | False Alarm | Real Alarm VUI Scenarios (Solution 3)
When surveying users* about their experience with false alarms (times that a smoke detector was triggered but the reasoning was not urgent), the following numbers were reported:


20 participants stated that cooking was the cause of
the majority of their false alarms

14 participants stated that the steam from their shower was the cause of
the majority of their false alarms

8 participants stated that a low battery was the cause of their false alarms

16 participants stated that they had
never experienced a false alarm


*Users of the current product were assumed to be the general public, 
given that smoke | fire detectors are commonplace in almost all residential and 
work environments and spaces.
Has your fire alarm ever gone off 
for anything that was NOT an emergency?

If yes, what set it off?
As a user, I want to easily monitor and turn off false alarms with the least amount of stress possible.”
2,055,000*
The estimated number of false fire alarms in the US each year.

*Based on Baltimore City’s false alarms x5 for the state of MD and then multiplied by 50 for approx. number of false alarms nationwide.
“We detect a fire–Is there an emergency?”
“We detect a fire–Is there an emergency?”
“Is this a false alarm?”
“Would you like to call “911?”
“Would you like to turn the alarm off?”
“Okay–the call has been placed–response units are on the way.”
“Okay, turning off now.”
No
Yes
Yes
Yes
Yes
VUI
VUI
VUI
VUI
VUI
VUI
VUI
Proposed Solutions
In order to accomodate as wide a range of users as possible, and to effectively suit thier 
needs, three solutions were proposed to make the common household fire alarm more efficient:

1. Analog switch that would be mounted on a wall or flat surface
For older users who either don’t have access to modern technology, or don’t wish to adopt it.

2. VUI Interface that would work through smarthome devices such as Amazon’s Alexa or Google Home
For users that don’t have a mobile device on hand, or cannot immediately access an analog switch.

3. A mobile application or integration that works with the smart home device
For situations where audio is not best suited.


* All three solutions would work interchangably, but would not require all three to function.
/03
Solution
Task Analysis, VUI, Touch Interface, Lo-Fi App Wireframes
CASE STUDY
Set Off False Alarm
Activate Analog Interface
Cancel Alarm
Test
Reset
Activate Visual and Tactile Alert
Initiate Dialogue via Alexa, Google
Cancel Alarm
Deactivate Alarm
Confirm Emergency
Activate 911 Call
Ignore Alert
Activate 911 Call
Activate VUI
Activate Phone App
Cancel Alarm
Confirm Cancellation
Deactivate Alarm
Confirm Emergency
Activate 911 Call
Don’t React
Activate 911 Call
Analog Device (Solution 1)
Alarm features: Motion Night Light, LED Warning Light, and Bluetooth Connection (For Smarthome Devices)
Analog Remote features: Bluetooth Connection, “Silence False Alarm”, “Reset System”, “Test Battery”, and “Test System”.
Mobile App | Smart Home App Integration (Solution 2)