1 TECHNICAL REPORT – THE LOUNGE CHAIR OF THE FUTURE TABLE OF CONTENTS 1. Introduction to the project 2. Introduction to smart textiles 3. Overview of how smart textiles can be applied to our chair 4. Removing the power cable 5. Related products 1. LOUNGE CHAIR OF THE FUTURE During 2011 the companies LINAK Danmark A/S, Anders Nørgaard Design, Schultz Seating Systems A/S and Alexandra Instituttet A/S work together on creating a lounge chair of the future. The project is called “The Intelligent and Interactive Chair” (In Danish: “Fremtidens interaktive stol”) and the vision is to create a chair that fulfills three quality requirements. 1. Design 2. Ergonomic 3. Intelligence The project aims to bring together good design, smart (or intelligent) textiles and ergonomic seating capacities to develop a lounge chair with innovative capabilities. Initial the focus of the chair was the elderly. However, it was later chosen to widen the focus on other segment than the elderly. The goal of the project is to develop a chair that can be presented at trade fairs during 2012. The project is funded by iKraft 1 . 2. WHAT ARE SMART (OR INTELLIGENT) TEXTILES? 2 3 Smart textiles are, in short, textiles that act. It is textiles that changes shape, color, and function according to your needs. Textiles which smell (in the good way). Textiles that exchange information and communication with each other, you and the environment. Textiles that regulate you (temperature, perspiration etc). Textiles that entertain. Textiles that keep you dry. Textiles that lights up. Textiles that monitor your health. Textiles that know and understands you. Textiles that takes care of you. Textiles that reveal and Textiles that camouflage you. The concept of smart textiles (also known as intelligent textiles or e-textiles in the literature), has evolved from the concept of wearable computers. The first generation of wearable computing consisted of electronics that were bodily worn, but not integration into the clothes 4 .This has evolved into the development of surface mounted electronics and later into electronics integrated into yarn, such as the Textro-yarns® by Textronics 5 which has conductive capabilities. 1 http://www.ikraft.dk/innovationspuljen 2 Section is partly based on: “Electrotextiles: concepts and challenges”, by Wagner et al. In International Journal of High Speed Electronics and Systems 2002 3 Section is partly based on: http://www.intelligentetekstiler.dk/2010/01/26/introduktion-til-intelligente-tekstiler/ 4 Pictures from: http://306is.blogspot.com/2007/04/history-of-wearable-computers.html , http://creativetech.inn.leedsmet.ac.uk/staff/rb/Wearable.html and http://www.coolest-gadgets.com/20080120/turnout-gear-from-viking/ 5 http://www.textronicsinc.com/yarns/
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1
TECHNICAL REPORT – THE LOUNGE CHAIR OF THE FUTURE
TABLE OF CONTENTS 1. Introduction to the project
2. Introduction to smart textiles
3. Overview of how smart textiles can be applied to our chair
4. Removing the power cable
5. Related products
1. LOUNGE CHAIR OF THE FUTURE During 2011 the companies LINAK Danmark A/S, Anders Nørgaard Design, Schultz Seating Systems A/S and Alexandra
Instituttet A/S work together on creating a lounge chair of the future. The project is called “The Intelligent and
Interactive Chair” (In Danish: “Fremtidens interaktive stol”) and the vision is to create a chair that fulfills three quality
requirements.
1. Design
2. Ergonomic
3. Intelligence
The project aims to bring together good design, smart (or intelligent) textiles and ergonomic seating capacities to
develop a lounge chair with innovative capabilities. Initial the focus of the chair was the elderly. However, it was later
chosen to widen the focus on other segment than the elderly. The goal of the project is to develop a chair that can be
presented at trade fairs during 2012. The project is funded by iKraft1.
2. WHAT ARE SMART (OR INTELLIGENT) TEXTILES?2 3
Smart textiles are, in short, textiles that act. It is textiles that changes shape, color, and function according to your
needs. Textiles which smell (in the good way). Textiles that exchange information and communication with each other,
you and the environment. Textiles that regulate you (temperature, perspiration etc). Textiles that entertain. Textiles
that keep you dry. Textiles that lights up. Textiles that monitor your health. Textiles that know and understands you.
Textiles that takes care of you. Textiles that reveal and Textiles that camouflage you.
The concept of smart textiles (also known as intelligent textiles or e-textiles in the literature), has evolved from the
concept of wearable computers. The first generation of wearable computing consisted of electronics that were bodily
worn, but not integration into the clothes4.This has evolved into the development of surface mounted electronics and
later into electronics integrated into yarn, such as the Textro-yarns® by Textronics5 which has conductive capabilities.
1 http://www.ikraft.dk/innovationspuljen
2 Section is partly based on: “Electrotextiles: concepts and challenges”, by Wagner et al. In International Journal of
High Speed Electronics and Systems 2002 3Section is partly based on: http://www.intelligentetekstiler.dk/2010/01/26/introduktion-til-intelligente-tekstiler/
http://creativetech.inn.leedsmet.ac.uk/staff/rb/Wearable.html and http://www.coolest-gadgets.com/20080120/turnout-gear-from-viking/ 5 http://www.textronicsinc.com/yarns/
2
As the above shows, smart textiles and smart furniture can be many things. However, in contrast to traditional textiles
or furniture - they act.
CATEGORIES OF SMART TEXTILES
There are two main domains of smart textiles
1. (Surface) Treated Textiles: By giving yarn surface treatment, using coating or changing the structure of the
fibers it is possible to change the properties of the textile. A classic example is water-proof jackets.
2. Textiles and electronics: These types of smart textiles are fabrics that allow electronic components to be
embedded in them6.
In the next section we will see how we imagine smart textiles can be applied in our context and in section 5 we
present an array of products and projects related to smart textiles.
6 http://en.wikipedia.org/wiki/E-textiles
3
3. SMART TEXTILES IN OUR CHAIR We conducted a literature study to get insight in the state of the art of smart textiles. On top of that we conducted a
number of workshops and interviews with potential consumers and a wide array of professionals and researchers.
This has given us insight into the possible match between technology opportunity and user needs. Also, see section 5
on “related products” for more information about projects related to smart textiles.
Known possibilities related to our chair:
Heating & cooling
o This is requested by nurses (ergo-therapists) and patients alike. Heating and cooling can be used for
relaxation as well as pain relief.
Energy scavenging to remove power cable and to make more environment friendly (not using carbon based
energy). Solar power, pressure energy. For large actuators (requiring more energy) we can perhaps not
harvest energy enough. Scavenging is perhaps only for luxery version of furniture, designed for low power
consumption (and which can be placed as a normal chair)
Monitoring capabilities
o Measuring the vital parameters of the user.
o Sensor for body temperature, smell, pressure, pulse, perspiration, breathing, and calorie burn rate.
Material related options
o change color today
o Dirt repellant.
o self-cleaning
o Water repellant
o other treatments, antistatic, flame-retartent, electric conducting, magnetic
o breathable
o anti-bacteria
o containing, sponge like material (e.g. for incontinentia)
o Fibers can light and change color
Actuator possibilities
o Movement
o Help to get in and out of the chair
Integration possibilities
o Remote control (television, stereo. house, mobile) GPS
o Build in phone, browser, television (LED textile display)
o Audio (Integration with audio or Hi-Fi systems)
Communication
o Ultrasound, infrared
o RF-communication, Bluetooth, RFID, Wi-Fi
Power supply
o Textile batteries
o Wireless energy
Sensing
o react/measure friction
o pressure (the chair put pressure on your body)
o sense where you fingers (arms, feet, etc) are (as the airguitar)
4
4. REMOVING THE POWER CABLES Intelligent furniture is, as previously mentioned, furniture with integrated textiles or electronics that allow the
furniture to do things that was not possible with legacy textiles/materials. It is the intention that features such as
built-in screens, speakers, smart textiles (for instance dirt or water repellant) can be added later in the project phase.
To enable these features the chair will need electric power. However, the end users are not interested in having a
cable plugged into their char – so we need to remove the cables. How this can be achieved will be analyzed in this
section. In this section we will consider three technologies which could be used in the lounge chair of the future:
wireless energy transferal, energy harvesting and the use of batteries.
4.1 WIRELESS ENERGY
In order to remove power cables from “the intelligent and interactive chair of the future” we need to find energy for
the actuators (a small engine that allows the chair to move, e.g. move the backrest or give massage) and sensors.
We can retrieve (i.e. harvest) this from several sources:
Body heat
Body movement
Sunlight
Cable-less power transfers (e.g. a beam with RF-based energy)
The chair can (for our purposes here) be divided into two cases
nursing usage (elderly, back pains, etc)
private, recreational usage (for normal fit people)
In the nursing usage scenario it will be problematic if the furniture can’t move because of lack of power. The two body
based energy harvesting methods (body heat, body movement) have periods where they may not be able to provide
the required energy (consider that the user who just have sat down in the furniture and then adjust the furniture
several times). The sunlight energy harvesting may fail if the sun is not shining for prolonged time.
In the private, recreational usage, if we run out of energy, we may ask the user to provide the energy for us (e.g. by
asking the user to plug the chair into the power outlet or (stupid example) by providing a lever that the user can push
back and forth to generate energy). Still we may want to avoid ending up with a product that can run energy dry. Note
that body heat will provide energy as long as the user is there, but we expect that energy to be low.
It is also important to recognize, that some features are more energy demanding than others. Some of the more
"Wireless power transfer via strongly coupled magnetic resonances", By A. Kurs; A. Karalis, R. Moffatt, J.D. Joannopoulos, P. Fisher, M. Soljačić , Science (July 2007), see also http://en.wikipedia.org/wiki/Inductive_charging
Mid-range coil to coil efficiency 50% efficiency (2m, induction) and 75% (1m, induction)
Near-range system efficiency 94% (8mm, induction)
LEADING WIRELESS POWER TECHNOLOGY PROVIDERS 14
1. Powermat – Induction mat. They have recently released wireless charging mat whichcosts about 100 to 200
dollars depending on how many devices you want to charge. It requires a casing for the device.
2. WildCharge – Induction mat. Wire free chargers available for sale. Supports iPhone, BalckBerry and other
phones. Costs about 80 to 100 dollars including charging skins.
3. WiTricity – Designed for Original Equipment Manufacturers (OEM’s) to embed directly in their products and
systems. Expected to be available in early 2010. A demo-kit and developer-kit can be purchased at the time
of writing. The company is founded by Marin Soljacic from MIT. Uses medium distance magnetic induction.
4. Fulton Innovation – eCoupled – Designed for Original Equipment Manufacturers (OEM’s) to embed directly in
their products and systems
5. Powercast RFId radiation based, RFId range (915MHz), detectors can have up to 70% efficiency.
12
"Wireless power transfer via strongly coupled magnetic resonances", By A. Kurs; A. Karalis, R. Moffatt, J.D. Joannopoulos, P. Fisher, M. Soljačić , Science (July 2007) 13
www.PowerCastCo.com 14
http://www.wirelesspowersupply.net
8
6. WiPower – Charging Pad based technology available to Original Equipment Manufacturers (OEM’s) only
7. SplashPower (Aquired by ecoupled, 2008)
8. Mojo Mobility - - Does not seem to have actual products but want to create MojoPad.
9. PowerBeam (optical radiation based), detectors can obtain 50% efficacy. Wall-to-wall is 15%-30%,
There is a lot of attention around induction based charging stations for mobile phones PDAs, laptops, etc.
One solution could be to hide the “mat”+cable below a carpet and then place the chair above the mat.
Another solution is to use light point to point and install a sender in the ceiling and charge in that way.
Another solution is to use infrared. Infrared is furthermore more forgiving in terms of bending around obstacles.
SAFETY ISSUE The eye is the most problematic tissue
15 when it comes to laser safety as this is the part of the human body that first
takes damage.
At visible wavelengths (400nm-780nm) the eye’s blink reflex handles minor incidents. However for infrared light and
ultraviolet light the blink reflex does not work, and this courses damage to various parts of the eye.
Maximum Permissible Exposure (MPE) is measured in (W/cm^2) or (J/cm^2. It usually set at 1/10 of the level that has
50% risk of generating damage. Below is the graph of MPE as a function of exposure time:
Note MPE is here measured in W/cm^2 and this is the measurement for eyes.
From the graph we get that Power levels less than 1mW/cm^2 should be safe for humans for a few seconds, more for
certain wavelengths.
4.2 ENERGY SCAVENGING16
Scavenging energy (or energy harvesting) from ambient vibrations, wind, heat or light could enable smart sensors to
be functional indefinitely.
Several academic and commercial groups have been involved in the analysis and development of vibration-powered
energy harvesting technology, including the Control and Power Group and Optical and Semiconductor Devices Group
at Imperial College London, IMEC and the partnering Holst Centre, AdaptivEnergy, LLC, ARVENI, MIT Boston, Georgia
Tech, UC Berkeley, Southampton University, University of Bristol (UK), Nanyang Technological University, PMG
Perpetuum, Vestfold University College, National University of Singapore, NiPS Laboratory at the University of Perugia,
Columbia University, Universidad Autónoma de Barcelona and USN & Renewable Energy Lab at the University of Ulsan
(Ulsan, South Korea).
15
http://en.wikipedia.org/wiki/Laser_safety 16
http://en.wikipedia.org/wiki/Energy_harvesting
9
There are many small-scale energy sources that generally cannot be scaled up to industrial size:
Piezoelectric crystals or fibers generate a small voltage whenever they are mechanically deformed. Vibration
from engines can stimulate piezoelectric materials, as can the heel of a shoe.
Some wristwatches are already powered by kinetic energy (called kinetic watches), in this case movement of
the arm. The arm movement causes the magnet in the electromagnetic generator to move. The motion
provides a rate of change of flux, which results in some induced emf on the coils. The concept is simply
related to Faraday's Law.
Photovoltaics is a method of generating electrical power by converting solar radiation both (indoors and
outdoors) into direct current electricity using semiconductors that exhibit the photovoltaic effect.
Photovoltaic power generation employs solar panels composed of a number of cells containing a photovoltaic
material.
Thermoelectric generators (TEGs) consist of the junction of two dissimilar materials and the presence of a
thermal gradient. Large voltage outputs are possible by connecting many junctions electrically in series and
thermally in parallel. Typical performance is 100-200 μV/K per junction. These can be utilized to capture
mW.s of energy from industrial equipment, structures, and even the human body. They are typically coupled
with heat sinks to improve temperature gradient.
Micro wind turbine are used to harvest wind energy readily available in the environment in the form of
kinetic energy to power the low power electronic devices such as wireless sensor nodes. When air flows
across the blades of the turbine, a net pressure difference is developed between the wind speeds above and
below the blades. This will result in a lift force generated which in turn rotate the blades. This is known as the
aerodynamic effect.
Special antennae can collect energy from stray radio waves or theoretically even light (EM radiation).
Biomechanical energy harvesters are also being created. One current model is the biomechanical energy harvester of
Max Donelan which straps around the knee. Devices as this allow the generation of 2.5 watts of power per knee. This
is enough to power 5 cell phones.
Piezoelectric systems can convert motion from the human body into electrical power. DARPA has funded efforts to
harness energy from leg and arm motion, shoe impacts, and blood pressure for low level power to implantable or
wearable sensors. The nanobrushes of Dr. Zhong Lin Wang are another example of a piezoelectric energy harvester.
They can be integrated into clothing.
SOLAR POWER
Using Solar power is another option. Using solar power – or photovoltaics – it is possible to convert sunlight into
electricity17
. Solar power technology is rapidly developing and is being integrated into various products as an
alternative to batteries. An example is the Power Purse18
(see picture below) from 2008. It is a bag which outer surface
is covered with solar panels that absorb the sun’s rays and create electricity used for powering everyday gadgets.
17
“Photovoltaic solar energy - development and current research”, EC report on solar energy, 2009 18
is another example. It’s a solar-charging tablet case for tablets such as the iPad. According to
the manufacturer it “gets an hour of iPad video playback for every hour of direct sunlight, coming to 10 hours
for a complete charge,”. Which is pretty decent, but there is still a long way to go (it takes 3,18 hours to charge an
iPad using the standard 10w iPad charger according to a Gismondo test20
).
Solar power is an interesting source of energy, but it is most likely not suitable for purpose.
4.3 BATTERIES
Yet another option is the use of rechargeable batteries.
There is not as much power loss (compared to wireless energy) when the rechargeable batteries get charges and,
since it is a mature technology, it is easy to implement it in the chair. Batteries however have the drawback that they
“self discharge” and some batteries are rather heavy.
Common rechargeable battery types21
22
:
Lead-Acid (Gel Cells): Commonly used as a car battery. Despite having a very low energy-to-weight ratio and a low energy-to-volume ratio, their ability to supply high surge currents means that the cells maintain a relatively large power-to-weight ratio. These features, along with their low cost, make them attract make them attractive for use in motor vehicles to provide the high current required by automobile starter motors. They are moderately expensive.
Nickel Cadmium (Ni-Cd): NiCd batteries are often used in wireless telephones, emergency lighting, and other applications such as remote-controlled electric model airplanes. The primary trade-off with NiCd batteries is their higher cost and the use of cadmium (being a heavy metal it is an environmental hazard, and is highly toxic).
Nickel Metal Hydride (Ni-MH): A NiMH battery can have two to three times the capacity of an equivalent size nickel-cadmium battery. Compared to the lithium-ion cell, the volumetric energy density is similar but self-discharge is higher.
Lithium-ion (LIB): One of the most popular types of rechargeable battery for portable electronics with one of the best energy densities (i.e. energy amount stored per unit volume) and a slow loss of charge when not in use.
o Advantage: They come in a wide variety of sizes and are much lighter than other energy-equivalent rechargeable batteries. Lower self-discharge rate (5-10% per month).
o Disadvantage: It is very expensive. Furthermore the cell's capacity diminishes over time. The increase in internal resistance reduces the cell's ability to deliver current (a problem that is more pronounced in high-current applications). The decrease means that older batteries do not charge as much as new ones. If overheated or overcharged, Li-ion batteries may suffer cell rupture and – in extreme cases – to combustion.
RECHARGEABLE BATTERIES COMPARED23
Battery Type Total Capacity Self-Discharge Rate Comment
Nickel-Metal Hydride
(NiMH)
Up to 1,000, AAA.
Up to 2,700 mAh, AA.
Available capacities vary
widely.
Does not hold charge well
over long periods.
Loses 4 percent per day,
much more in warm
temperatures.
Also works well in devices
that require sudden high
amperage discharge, such
as digital cameras.
Low Self Discharge
Nickel-Metal Hydride
(LSD NiMH)
Up to 800, AAA.
Up to 2,000, AA
Almost all LSD batteries sold
have close to these
capacities.
Holds charge well over long
periods.
Loses 15 percent per year,
very slightly more in warm
temperatures.
Also works well in devices
that require sudden high
amperage discharge, such
as digital cameras.
Nickel-Cadmium
(NiCd)
Up to 350 mAh, AAA.
Up to 1,000 mAh, AA.
Available capacities vary
widely. Check the mAh
rating before you buy.
Loses 1 percent per day,
slightly more in warm
temperatures.
Does not work well in
devices that require sudden
high amperage discharges.
Does not work well in digital
cameras, but does work
well in most other devices.
23
Based on http://www.calrecycle.ca.gov/ReduceWaste/power/rechbattinfo.htm
12
5. RELATED PRODUCTS
SMART FURNITURE
THE SMART SOFA FROM TRINITY COLLEGE, DUBLIN (2003)24 The sofa was developed in 2003 by scientists at the Trinity College in Dublin. The
sofa has a sensor on each leg which can measure who is sitting in the sofa based
on the person’s weight. Apart from measuring weight the sofa can give the user a
personalized greeting.
In 2003 Mads Haahr, one of the researchers, said that this was just the beginning
and that he envisioned a future where the sofa would be able to do much more:
set the temperature in the room based on the users comfort level or switch on
household appliances.
THE SENSECHAIR (2005)25, CARNEGIE MELLON UNIVERSITY (CMU) The SenseChair was a created at the Carnegie Mellon University in 2005 and
is part of the “project on people and robots” program. The aim of the
SenseChair project was to create an armchair that could be used as a robotic
assistant for elders’ homes.
The SenseChair is designed to provide non-invasive feedback to the owner of
the chair. The main functionality of the SenseChair is to monitor sitting
position and lack of activity (i.e. dozing off) in the chair. If the user falls
asleep (as is pictured in the figure) during the evening it is advantageous to
wake the user so that he or she can sleep in her bed. In this scenario the
chair will wake the user using vibration motors embedded in the chair and,
to avoid accidents, turn on the light underneath the chair to ensure that the
user can see.
The SenseChair was seen as a platform for research into designing
technology for elders, rather than a product. However, the chair has not