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Implicitly Human-Powered Devices

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This position paper explores how we can harvest energy from human interaction with digital devices in an implicit way. Primarily useful for batteryless devices and sporadic interactions, we conceptualized several implementations where no additional energy-generating interactions are needed. Instead, we generate energy from human exertions (already) required to interface with the device. Using six sketched concepts, we show how this can be achieved using existing interactions, or intuitive alternatives. Here, the energy generation is rather 'hidden' and in some cases can enhance the interaction experience. Energy harvesting thereby follows form, rather than form follows energy harvesting.
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Implicitly Human-Powered Devices
David Verweij
Open Lab
Newcastle University
Newcastle upon Tyne
d.verweij2@ncl.ac.uk
Dan Jackson
Open Lab
Newcastle University
Newcastle upon Tyne
dan.jackson@ncl.ac.uk
Karim Ladha
Open Lab
Newcastle University
Newcastle upon Tyne
karim.ladha@ncl.ac.uk
David Kirk
Open Lab
Newcastle University
Newcastle upon Tyne
david.kirk@ncl.ac.uk
Author Keywords
Energy Harvesting; Human-powered; Interaction
Design;
CSS Concepts
• Human-centered computing~Human computer
interaction (HCI)~Interaction Devices;
• Hardware~Power and energy~Energy generation and
storage
Introduction and Background
To incorporate energy harvesting in consumer
electronics, we can use a variety of ‘natural’ energy
sources, including kinetic (e.g. wind), thermal (e.g.
waste heat) and solar each with their own power
density and efficiency [3]. However, on-device energy
harvesting for multifunctional devices, such as
smartphones or smart thermostats, will often not
suffice as the sole energy source. In the case of
human-powered energy harvesting, this might even
lead to dissatisfactory user experiences [16]. Instead,
self-sustainability seems more promising for emergency
scenarios [16] (e.g. power outages) or single-purpose
devices such as (ambient) sensors. Even still, the
expectations of (near) real-time data logging, combined
with excessive battery lives (e.g. ~2 years for a
temperature and door sensor [8]) makes arguing for
on-device energy harvesting difficult.
Except, batteryless devices do have their potential. Not
only do they combat the environmental harm of
(lithium) batteries [11], they can also lower production
costs, scalability and simplify functionality. In
Abstract
This position paper explores how we can harvest
energy from human interaction with digital devices in
an implicit way. Primarily useful for batteryless devices
and sporadic interactions, we conceptualized several
implementations where no additional energy-generating
interactions are needed. Instead, we generate energy
from human exertions (already) required to interface
with the device. Using six sketched concepts, we show
how this can be achieved using existing interactions, or
intuitive alternatives. Here, the energy generation is
rather hidden’ and in some cases can enhance the
interaction experience. Energy harvesting thereby
follows form, rather than form follows energy
harvesting.
Permission to make digital or hard copies of part or all of this work for personal or
classroom use and for all other uses - must be acquired by contacting the first author.
© Copyright on all original content in this paper is held by the owner/author(s).
This position paper was a workshop contribution for the Self Sustainable CHI workshop at
CHI’20, April 25–30, 2020 see also http://cs.swansea.ac.uk/~SelfSustainableCHI/
DOI: doi.org/10.13140/RG.2.2.23790.43846
particular, human-powered single-purpose devices can
offer on-demand functionality with digital services,
without requiring any maintenance. To demonstrate,
we have (re)designed 6 products that are batteryless
and human-powered. Rather than introducing
additional mechanisms and interactions to generate the
required energy, we embedded the energy harvesting
within the core interaction. As such, we allow for an
implicit (and intuitive) human-powered interaction.
These designs exemplify how energy harvesting can be
suitably integrated and contribute to the development
of future self-sustainable devices.
Human-Powered
A familiar human-powered device is the dyno torch,
where a crank or squeeze mechanism will charge a
battery to fuel a torch, battery bank or other battery-
equipped device. This implementation is a good
example of active and human-powered microgeneration
as elaborated on by Pierce and Paulos in [16]. Most
human-powered microgeneration implementations
require additional interactions (e.g. to build up a
charge), which often differ from the actual interaction
with the device. This is evident in most existing human-
powered equipment, such as these dyno torches, but
also more novel prototypes such as a squeezable
mobile phone [16]. Instead, we identify opportunities
where the microgeneration is embedded in the
interaction with the device for cases where this small
and sporadic amount of energy suffices.
1
Assuming a required energy of ~5 mJ/cm2 and a 5.5” (100 cm2)
screen, combined with a geared up generator or alternative
mechanism such as [20].
(Re)Designs
The overarching theme in our redesigns lies within
services that produce digital output upon direct
interaction. This means that without any interaction,
and due to the lack of battery, no output is produced
ever. In addition, the required energy for these services
needs to be low in the order of milli-Watts. Put
together, these fed into our following batteryless
(re)designs.
Page-Turner
We imagine a simplified e-reader (see Figure 1) that
houses a 5.5” e-ink display. The reader has enough
non-volatile memory to store a single e-book. At the
bottom of the device, an ergonomically shaped handle
allows itself to be pivoted around its centre. When the
user rotates the handle anti- or clockwise by 180
degrees, enough energy
1
is generated to load the
previous or next page respectively. The bistability of e-
ink displays enables the loaded page to stay in view
without any supplied power. Permanent magnets
ensure a ‘snappy’ and non-linear interaction with the
handle, similar to turning a physical book page, as well
as keep the handle horizontally in place when not in
use. Its batteryless design offers no wireless
connectivity, and as such requires the user to upload
an e-book using their phone (equipped with NFC), or
via a regular USB cable.
Figure 1: An E-book that only stores one digital book.
Rotating the handle 180 degrees will generate the energy to
‘flip’ to the new page, and thereby acts as an input.
Figure 2: A remote gate equipped with Pivot Push. Any energy
harvested from pivoting, such as opening and closing the gate,
sends a single push notification to the central home unit for
further processing.
Pivot Push
Particularly useful for remote letterboxes or garden
gates, the Pivot Pish is an inconspicuous mechanism
embedded in a hinge (see Figure 2). This mechanism
generates energy from a person opening and
(optionally automatically) closing it, just enough to
connect and send a notification to a centralized unit
wirelessly. For letterbox designs, the small amount of
generated energy (around 3 mW based on [7])
required this design to be placed within 10-20 meters
of the central unit. It then utilizes the common low-
power Zigbee wireless protocol to send its message.
For larger designs, such as a garden gate, a larger
amount of energy (~1W based on [14]) allows the use
of the Long Range (LoRa) wireless protocol (possible
with ~10 mW [5]) to reach distances of up to 2-3 km.
This implementation can be put to use for security
monitoring or measuring traffic at remote locations
such as on remote hiking trails.
Snappy Sensors
Similar to the Pivot Push, Snappy Sensors (see Figure
3) generate energy by opening and closing doors,
windows, and alike. Replacing existing magnetic
catches, the embedded microcontroller draws energy
upon opening or closing the object. This energy (~5
mW based on [9]) allows a single wireless Zigbee
message to reach the central home unit. Snappy
Sensors can act as security alarms if installed on
windows, or offer a low-impact method for monitoring
relatives in-home care.
magnets
long-range
pivot push hinge
spring loaded
concealed
system
Figure 3: Using snappy sensors on kitchen cabinets
introduced digital services to everyday interactions at home.
Figure 4: Mimicking commercial fingerprint reading door
handles, this Security Door Handler is powered by a single
(semi) rotation of a normal looking door handle.
Security Door Handler
By increasing the gear ratio from the page-turner
mechanism, this door handle (see Figure 4) will verify
the thumb fingerprint from the hand that turns it. Upon
rotating the Security Door Handler by 60 degrees,
authentication using the 10 locally stored fingerprints is
performed. At the same time, a spring is pulled to
when authenticated - retract the locking deadbolt. A
keyhole provides backup entry using a master key.
Managing fingerprint authentication is done via a
regular USB cable and provided computer software. The
Security Door Handler is particularly useful to retrofit
inhouse or remote doors that multiple people need
access to.
Cold Casting Coat
By combining textiles with (flexible) Peltier elements
(similar to [1]), we imagine a light-emitting coat (see
Figure 5). This coat takes body heat to directly power a
small number of LED lights on the back and arms of
this coat. In more extreme movements, such as
cycling, or with colder temperatures in winter or at
night, the intensity of the lights will increase. A simple
timer circuit will ensure a noticeable light pattern as
well as reduced energy usage of the embedded lights.
This coat augments any lights already in use (as their
low brightness cannot replace them) and increases
visibility towards fellow road users.
The Paralyzed Digital Photo Frame
Stretching the definition of what is human-powered, as
well as implicit, we imagine the use of a mobile phone
as interface and power source through the concept of
the Paralyzed Digital Photo Frame (see Figure 6).
Inspired by Dementyev’s NFC-powered companion
display [6], this frame is powerless in the sense of no
snappy sensor
surface antenna
magnet
pulls on the deadbolt,
regardless of
authentication
releases the deadbolt if authenticated
fingerprint
reader
latch bolt will
always open
Figure 5: Using the temperature difference between the inside
and outside of a jacket, embedded LED lights are
thermoelectrically powered to increase its wearer visibility.
Figure 6: A barebone ‘paralyzed’ photo frame offers an
efficient single purpose and aesthetically pleasing way to
display various pictures. With the help of a smartphone, this
product offers additional digital services only when needed.
battery, as well as its computational thinking. It
embeds a large e-ink display, showing a single picture
indefinitely until its owner chooses to replace it. When a
phone is placed into the embedded phone holder, the
hidden NFC tag prompts an application on the phone.
The user is then able to select a single picture to be
displayed on the frame for which power (and data) is
transferred via NFC (identical to [6]). The slow, but
evident, degradation of the screen’s bistability - and
thereby the sharpness of the image motivates the
owner to update the photo frame every month or so.
Towards Implicitly Human-Powered
The presented concepts show how human-powered
energy harvesting can be embedded in an intended
interaction with the device, hidden, and potentially
unconsciously performed. We thereby aimed to
intrinsically link minimal and familiar interaction with
their energy harvesting needs, such that energy
harvesting follows form (within the constraints of
energy harvesting mechanics), rather than form follows
energy harvesting. In addition, the introduced load-
inducing mechanisms have the potential to enrich the
interaction with carefully designed tactile feedback. This
contrast jarring, potentially unintuitive (and
dissatisfactory [16]) user experiences from adding
separate crank or squeeze mechanisms to generate
power.
Simply Single Purpose
In our design exploration, we experienced that
implicitly embedding energy harvesting is difficult if
not impossible - in most devices and services we use
nowadays, such as sensors and remote controls. Yet,
equally, this exploration resulted in novel use cases for
human-powered and potentially intuitive and natural
blinking LED
lights
embedded
LED
inside patch (on skin)
outside patch
passe-partout
frame
phone holder
large multi-color
e-ink display
NFC power
and data
transfer
interactions. It led to simple, energy independent and
human-initiated services: a clear commonality amongst
our concepts. This contrasts most consumer electronics
that aim to provide a constant (or regular) connection
to inform their status (e.g. temperature sensors) or
offer multiple features. Instead, we argue our ‘simple’
conceptual products offer serenity in an age of always-
on, and on-demand access permitted they fulfil their
owners need in the presented edge cases.
Considerations around privacy and security are hereby
potentially simplified. Though we admit, this would
require some refinement, particularly in products that
do need to connect with cloud services.
Context of Energy Use
The benefits of (human-powered) harvested energy
seem most valuable in its direct context of use, as
argued by Loh and colleagues’ [12]. We further expand
this notion to harvest energy through use, which
would contribute to the relationship with energy as a
more interactive rather than background technology
[15, 16]. We found, and drew inspiration from, existing
work that closely relates to this notion, including
consumer products (such as the dyno torch) and
academic work that equally contribute to our train of
thought. For example, Strothmann’s bike lights [13]
are solely powered on the magnetism from the rotating
bike wheels, where Philips’ Hue tap switch [18] is
powered on the kinetic energy from the button press.
Adding to this batteryless approach are solutions such
as a (patent for a) squeezable fuelless cigarette lighter
[4], and the academically explored remote controls
from Villar and Hodges [19] and Badshah and
colleagues [2] where the power generative movement
doubles as an input. Using printed media, Karagozler
and colleagues have shown how interaction with
interactive printed media can be used to power these
interactions using ‘paper generators’ [10].
The context of energy use in our redesigns varied,
ranging from changing the content on the device itself
to notifying external services about the presence of
unaware passersby during a hike. We imagine this
range is easily expanded by adapting, for example, the
snappy sensors to enable smart home automation (e.g.
turning on the light upon entering your home). We
might then consider the context of use for their
generated energy decoupled, which could potentially
weaken users’ sense of the devices energy harvesting
nature [12]. Instead, designing these services through
an implicit human-powered lens resulted in products
with the security and peacefulness of a never-on-
unless-used architecture. Similarly, their human-
powered need ensured ‘on-demand’ functionality, whilst
aiding in the mitigation of the information overload of
our continuous everyday data collection.
Future developments
With more developments in wireless connectivity and
charging (such as power over Wi-Fi [17]), people might
argue against batteryless designs. On the contrary! As
we have hopefully shown, human-powered designs
offer more, alternative, and potentially preferable
experiences than just environmentally friendly, energy-
independence and self-sustainability. These experiences
can also be applied to non human-powered devices,
using other energy sources based on human
interaction. This is demonstrated by the Paralyzed
Digital Photo Frame concept. Our next steps are to
further discuss our proposal with like-minded
researchers and designers. In particular, we seek to
refine the concept of implicitly human-poweredness,
and further investigate its usability implications such as
user expectation and operation reliability.
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