KTF Engineering Report for Scent Computer 13th Nov PDF

7/29/2019 KTF Engineering Report for Scent Computer 13th Nov PDF

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KTF Engineering Report Lyndsay Williams 13th

November 2011

Engineering notes for KTF rainbow scent computer

Lyndsay Williams 2011

[email protected]

www.sensecam.co.uk

13 November 2011

Draft V2

Note this document is a Hypertext document with links to references and videos and so printing is

not recommended.

This is a draftversion, please let LW know of any omissions.
mailto:[email protected]:[email protected]://www.sensecam.co.uk/http://www.sensecam.co.uk/http://www.sensecam.co.uk/mailto:[email protected]


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November 2011

Introduction

In 2010, Lyndsay Williams, Managing Director of Girton Labs, Ltd Cambridge, was asked by Jenny

Tillotson (PI) to assist in a grant application for KTF for a scent system. Williams had previously

designed fragrant Sensebooks in 2007-2008 as financed by East of England Development Agency and

coveredhere in the Guardian Newspaper.

The NEW KTF grant was to allow technology transfer of existing scent emission system to a pendant

and sleep computer. Central Saint Martins University employed Williams as an electronic engineer

and Senior Research Fellow for the engineering part of the project from June 2010. Williams was

responsible for electronic engineering, firmware and microcontroller system design and the

mechanical engineering was done by Raymond Oliver (COI) and team.

Existing technologies

Nichrome heaters

SenseBook, nichrome matrix heater from Girton Labs Ltd and Associates, East of England

Development Agency funded project, 2008. This was an interactive herb and spice cookery book.

When pages of the book were opened an optical sensor was used to detect an open page, a warm

lamp (LED) was lit up on the page, and fragrance was emitted which corresponded to the herb or

spice. This was useful to help people choose a herb or spice for cooking by associating the fragrance

smell with the image of spice. A flickering flame was simulated in software using a LED. The circular

tabs below are moveable vents for the fragrance to be attached via a living hinge.

Sensebook prototype
http://www.guardian.co.uk/technology/blog/2008/dec/10/research-apple?INTCMP=SRCHhttp://www.guardian.co.uk/technology/blog/2008/dec/10/research-apple?INTCMP=SRCHhttp://www.guardian.co.uk/technology/blog/2008/dec/10/research-apple?INTCMP=SRCHhttp://www.guardian.co.uk/technology/blog/2008/dec/10/research-apple?INTCMP=SRCH


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November 2011

Example of Herb Cookery Book from Google Images

Turning a page stopped and started the fragrance emission , by (a) blocking fragrance by the

closed page (b) the optical sensor controlling the microcontroller heating of the scent and (c)

MEMs accelerometer sensor to detect orientation of book in space. The heater system consists of

an x/y matrix of nichrome wire heaters, with essential oils stored in a cavity created by a 3D printer.

A PIC 18FXX microcontroller and Darlington transistors were used to heat nichrome wire and

resistors. AAA batteries in the spine make the book compact and elegant. The use of an x/y matrix

allows minimal signals to be used from a microcontroller and so reduce cost and size.

X,Y heater matrix

An example is a 3 x 3 matrix allows 9 heaters and 4 x 4 matrix allows 16 heaters. The book had a

capacity of 256 fragrance samples using just 16 control lines in an 8 x8 matrix. The LEDs were based

on a Red Green Blue LED which used software mixing to get multiple colours.

RED GREEN BLUE LED


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This would allow warm amber for Frankincense, green for wood, red for a spice and other

permutations. This would allow the rainbow effect of multiple colour for scents as requested

by KTF project spec. The system was tested by Girton Labs on oils such as lavender and

Frankincense . A system using a disposable cartridge, like a toy cap gun was proposed. This

disposable cartridge system may be useful in future fragrance systems.

Girton Labs LoC 3D printed reservoir, 2011, with oil storage wells

Sensebook is inspired by the incense clock as here, invented by the Chinese over 1000 years ago.

Fragrance clock image fromhere

Example of circular gunpowder caps
http://en.wikipedia.org/wiki/Incense_clockhttp://en.wikipedia.org/wiki/Incense_clockhttp://en.wikipedia.org/wiki/Incense_clockhttp://www.springerimages.com/Images/LifeSciences/1-10.1007_978-3-642-04670-4_10-0http://www.springerimages.com/Images/LifeSciences/1-10.1007_978-3-642-04670-4_10-0http://www.springerimages.com/Images/LifeSciences/1-10.1007_978-3-642-04670-4_10-0http://www.springerimages.com/Images/LifeSciences/1-10.1007_978-3-642-04670-4_10-0http://en.wikipedia.org/wiki/Incense_clock


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Girton Labs Ltd example of sensing computer, Royal Mail stamp showed for scale

The use of nichrome wire as a reliable and small system for heating fragrances is wellknown , examplehereand patent referencehere.

A lightweight, portable device maintains at a warm temperature a quantity of animal scent,

particularly animal urine, which is used by hunters to attract animals. A battery operated heatingelement surrounding a chamber which removably (sic) receives a vial of the liquid scent maintains thetemperature of the liquid above freezing when the device is used outdoors in cold weather, andpreferably heats the scent to a temperature which closely imitates the fresh presence of live deer.

A demo of an orange nichrome heater using a diesel Glow Plug was demonstrated to the PI in 2010.

Some more work was needed on controlling temperature and heater feedback and this has now

been designed.

Johnson & Johnson ultrasonic nebuliser

This is aproven working scent distribution systembut would possibly be too large for pendant use

but satisfactory for the bedside sleep computer. The reservoir could be made smaller however.

InkJet Technology
http://en.wikipedia.org/wiki/Nichromehttp://en.wikipedia.org/wiki/Nichromehttp://en.wikipedia.org/wiki/Nichromehttp://www.google.com/patents?id=k7suAAAAEBAJ&printsec=frontcover&dq=4,771,563&hl=en&ei=hqC7Tq_QFYuu8QPqmOidBw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDAQ6AEwAAhttp://www.google.com/patents?id=k7suAAAAEBAJ&printsec=frontcover&dq=4,771,563&hl=en&ei=hqC7Tq_QFYuu8QPqmOidBw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDAQ6AEwAAhttp://www.google.com/patents?id=k7suAAAAEBAJ&printsec=frontcover&dq=4,771,563&hl=en&ei=hqC7Tq_QFYuu8QPqmOidBw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDAQ6AEwAAhttp://www.youtube.com/watch?v=BQdREWSuTAEhttp://www.youtube.com/watch?v=BQdREWSuTAEhttp://www.youtube.com/watch?v=BQdREWSuTAEhttp://www.youtube.com/watch?v=BQdREWSuTAEhttp://www.google.com/patents?id=k7suAAAAEBAJ&printsec=frontcover&dq=4,771,563&hl=en&ei=hqC7Tq_QFYuu8QPqmOidBw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDAQ6AEwAAhttp://en.wikipedia.org/wiki/Nichrome


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This was a system using Inkjet, computer controller developed by Williams and the inkjet system

PIs mechanical engineer in 2010. The system worked but there were some problems with

reservoir leakage that were not solved at the time but could be with an airlock design, see later in

document.

Prototype inkjet scent computer


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Girton Labs 3D printed Lab on a Chip Feb 2010

Girton Labs PIC based scent sensing computer 2010.

Some of above working technologies (nichrome, inkjet, ultrasonic) were suggested to be used for

the KTF project by LW but declined by the PI. No financial or licensing issues were discussed. Therewere technical issue re lingering of heated smells and non precise doses as required for the medical

applications. These problems have been fixed in the later Sensebadge designs, see end of

document. The living hinge stops the lingering smell problem, and a precisely manufactured 3D

printed reservoir controls the volume of solid or oil to presented to the heater.

The PI & COI decided to use Lab on a Chip technology as this would allow precise microfluidic

control of liquids and mixing. LoC could also provide the reservoir design. This LoC took several

months development by the mechanical engineers including Epigem to get to a stage where a

specification could be prepared by LW for the microcontroller interface.
http://en.wikipedia.org/wiki/Lab-on-a-chiphttp://en.wikipedia.org/wiki/Lab-on-a-chip


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Microcontroller requirements

The final scent mechanical system was provided as designed by Raymond Oliver & Epigem Ltd. This

was a Lab on a Chip and worked well as can be seen on video as in later pages in this document.

The microcontroller is used to switch on a Bartels micro pump , and then control a heater to

disperse scent. The timing details of this are covered in the C++ source code, but approximately

300ms was used to switch on the pump, and 10 seconds to control the heater. It could be seen that

precise amounts liquid estimated to within 1% could be delivered by the pump. The exact volume

delivered by the pump could be calculated as follows.

Pump on for 300ms, 5mm of liquid movement measured.

A cylinder with radius r units and length h units has a volume of V cubic units given by

The diameter of the cylinder was 2 * r mm.

(COI to advise actual diameter of Epigem LoC cylinder).

The triggering of the scent was to be done by detection of human stress as measured by an

accelerometer and a heart rate sensor. This was prior research and was IP developed by LW at

Microsoft Researchin approx 2001. It was noted in tests that heart rate would increase with stress.

An accelerometer was used to eliminate signals from physical movement that increased the heart

rate. An example on the chart in above link shows the stress caused by reading the contents of an

email.

Stress sensor design.

This is based on an ADX335 3 channel accelerometer ashereand Galvanic Skin Response Sensor for

Arduino ashere. Here isanother GSR circuitthat was evaluated. Here is an example of anArduino

heart rate monitor.

Due to limited days remaining in the contract in September (time was allocated at only 1.5

day/week for engineering) it was suggested by LW to use Galvanic Skin Response rather than

developing a heart rate sensor but the PI and CIO choose not to have this implemented .
http://research.microsoft.com/en-us/news/features/it_feels_the_earth_move.aspxhttp://research.microsoft.com/en-us/news/features/it_feels_the_earth_move.aspxhttp://research.microsoft.com/en-us/news/features/it_feels_the_earth_move.aspxhttp://www.analog.com/en/mems-sensors/inertial-sensors/adxl335/products/product.htmlhttp://www.analog.com/en/mems-sensors/inertial-sensors/adxl335/products/product.htmlhttp://www.analog.com/en/mems-sensors/inertial-sensors/adxl335/products/product.htmlhttp://arduino.cc/blog/category/sensors/galvanic-skin-response/http://arduino.cc/blog/category/sensors/galvanic-skin-response/http://arduino.cc/blog/category/sensors/galvanic-skin-response/http://theanthillsocial.co.uk/sites/theanthillsocial.co.uk/files/resources/iphoneInterface/BuildSheet.pdfhttp://theanthillsocial.co.uk/sites/theanthillsocial.co.uk/files/resources/iphoneInterface/BuildSheet.pdfhttp://theanthillsocial.co.uk/sites/theanthillsocial.co.uk/files/resources/iphoneInterface/BuildSheet.pdfhttp://www.kickstarter.com/projects/1342192419/pulse-sensor-an-open-source-heart-rate-sensor-thathttp://www.kickstarter.com/projects/1342192419/pulse-sensor-an-open-source-heart-rate-sensor-thathttp://www.kickstarter.com/projects/1342192419/pulse-sensor-an-open-source-heart-rate-sensor-thathttp://www.kickstarter.com/projects/1342192419/pulse-sensor-an-open-source-heart-rate-sensor-thathttp://www.kickstarter.com/projects/1342192419/pulse-sensor-an-open-source-heart-rate-sensor-thathttp://www.kickstarter.com/projects/1342192419/pulse-sensor-an-open-source-heart-rate-sensor-thathttp://theanthillsocial.co.uk/sites/theanthillsocial.co.uk/files/resources/iphoneInterface/BuildSheet.pdfhttp://arduino.cc/blog/category/sensors/galvanic-skin-response/http://www.analog.com/en/mems-sensors/inertial-sensors/adxl335/products/product.htmlhttp://research.microsoft.com/en-us/news/features/it_feels_the_earth_move.aspxhttp://research.microsoft.com/en-us/news/features/it_feels_the_earth_move.aspx


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Microcontroller choice

The use of a PIC, ARM or Atmel microcontroller was considered. Main requirements was minimum

specification of micro to meet small size, low power requirements , analogue sensing and controlmechanical actuators.

The 8 bit Atmel microcontrollerATMEGA168was chosen as theArduino Pro Mini platform allowed

for rapid prototyping of the system using C++ and existing libraries on the internet. The processing

power of a 32 bit ARM was not required by the KTF spec.

Here is aBill of Materialsfor the final scent computer design.

Battery choice.

This had to have a very small and thin form factor and the battery used was similar to as used in theiPod nano , a rechargeable Li Poly 3.7V 300mAhr battery, image below.

The next image shown is the final design of control electronics from LW.
http://www.atmel.com/dyn/products/product_card.asp?part_id=3303http://www.atmel.com/dyn/products/product_card.asp?part_id=3303http://www.atmel.com/dyn/products/product_card.asp?part_id=3303http://www.arduino.cc/http://www.arduino.cc/http://www.arduino.cc/https://docs.google.com/spreadsheet/ccc?pli=1&key=0AhE5J8OOKWlVdEdFeXlEQkRKVnM2RDdva29VWmxPUHc#gid=0https://docs.google.com/spreadsheet/ccc?pli=1&key=0AhE5J8OOKWlVdEdFeXlEQkRKVnM2RDdva29VWmxPUHc#gid=0https://docs.google.com/spreadsheet/ccc?pli=1&key=0AhE5J8OOKWlVdEdFeXlEQkRKVnM2RDdva29VWmxPUHc#gid=0https://docs.google.com/spreadsheet/ccc?pli=1&key=0AhE5J8OOKWlVdEdFeXlEQkRKVnM2RDdva29VWmxPUHc#gid=0http://www.arduino.cc/http://www.atmel.com/dyn/products/product_card.asp?part_id=3303


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Schematic of microcontroller circuit 10 Oct 2011

March 2011 PIC version


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Arduino scent computer August 2011

June 2011 sketch of scent pump


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3D CAD design of Scent computer before fabrication on PCB

PCB 40 x 60 mm

Left to right, PCB with Arduino Microcontroller , Li Poly Battery.

On RHS is the Epigem LoC pump withBartelspump.
http://www.bartels-mikrotechnik.de/index.php/mp6.htmlhttp://www.bartels-mikrotechnik.de/index.php/mp6.htmlhttp://www.bartels-mikrotechnik.de/index.php/mp6.htmlhttp://www.bartels-mikrotechnik.de/index.php/mp6.htmlhttp://www.bartels-mikrotechnik.de/index.php/mp6.html


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Rainbow LEDs are discrete red, orange, yellow, green, blue, violet, white. A single RGB led would

have been able to create many more colours but was not used.

Underneath the main PCB is the accelerometer PCB ashere.

Side view showing sandwich construction , from top to bottom, PCB, battery, LoC board

Here is a videoof LoC scent working.

Please email Lyndsay [email protected] permission to view this as is hosted on

Youtube (but not public) . Currently the following have been given permission for viewing, Jenny

Tillotson, Raymond Oliver, Jane Gibbs, Carole Gibbons.
http://www.sparkfun.com/products/9269http://www.sparkfun.com/products/9269http://www.sparkfun.com/products/9269http://www.youtube.com/watch?v=_w_kaUwIbXchttp://www.youtube.com/watch?v=_w_kaUwIbXcmailto:[email protected]:[email protected]:[email protected]:[email protected]://www.youtube.com/watch?v=_w_kaUwIbXchttp://www.youtube.com/watch?v=_w_kaUwIbXchttp://www.sparkfun.com/products/9269


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Potential leaking issues

The final Epigem LoC pump performed well as can be seen on video. There were no leakage

problems noticed. If however these are in issue in future, e.g. inverting the pump when worn on the

moving body, the leakage can possibly be fixed by use of an airlock , as designed into the Lab on a

Chip . Prior art of this method is as used on fermentation locks and also aircraft avionics with lead

acid batteries. As an aircraft can invert in flight, the lead acid batteries must not leak acid and so an

airlock is used.

Example of an airlock , the fold over is not required, only shown for compact designs.

This airlock can be fabricated using 3D printing.

Firmware

The firmware was created using Arduino C++ compiler. Here is a code fragment of C++ /Arduino

instruction to switch the pump on for two seconds and then switch off.

digitalWrite(MOSFET, LOW);

delay (2000);

digitalWrite(MOSFET, HIGH);

The full source code was emailed to PI & COI October 2011.


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Girton Labs PSOC and future electronic fragrance technology

The CypressProgrammable System on a Chipwill allow most of a fragrance circuit design to be

integrated on just one semiconductor. This can include microcontroller, MOSFET driver, heart rate,

GSR, accelerometer interface, power management and analogue interface. This will allow a much

smaller PCB as analogue and digital components are integrated onto one piece of silicon. Rapid

prototyping can be achieved as the FLASH memory (including analogue components such as op-

amps) can be reprogrammed in about 30 seconds as opposed to the >48 hour cycle of PCB

manufacture . PSOC will also allow a custom IC to be designed and any propriety design

information to be kept confidential within the chip. PSOCs can bepowered from 0.5V, i.e. solar

powered and the cost starts at 66p, (100 off) for the simplest variant. The ARM variant used by

Girton Labs has up to 60 I/O ports including analog which allows up to 60 sensing inputs for

Sensebooks. The built in MOSFET power drivers in the PowerPSOC series allow very small heater

drivers to be included on the chip. The PSOC also allow non touch proximity triggering of actuators

from a distance of a few cm. Multiple PSOC proximity sensors will allow left to right hand gestures

etc, technology here,CapSense,but via a large air gap.
http://www.cypress.com/?id=1353http://www.cypress.com/?id=1353http://www.cypress.com/?id=1353http://www.cypress.com/?rID=46529http://www.cypress.com/?rID=46529http://www.cypress.com/?rID=46529http://www.cypress.com/?id=1575http://www.cypress.com/?id=1575http://www.cypress.com/?id=1575http://www.cypress.com/?id=1575http://www.cypress.com/?rID=46529http://www.cypress.com/?id=1353


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Image here of Girton Labs PSOC firmware design reading sensors ,the ARM PSOC is approx. 8 x8

mm and in bottom right hand corner. PCB by Cypress Semiconductors. Girton Labs will be continuing

research with PSOC based Sensebooks, using nichrome heaters and other designs of Lab on Chip.

The oil well will be fabricated in transparent acrylic as image below with the new airlock design to

prevent leaks. The transparent case also allows light shading and mixing of Red Green Blue LEDs to

allow multicolour light cycling displays. Here is demo videoin Girton of similar, note only 12 Watts

power is used, i.e. can be used on batteries. Here is an example using an Atmel microcontroller, the

same as used in KTF project,video link here.

Transparent 3D design for LoC
http://www.youtube.com/user/sensecam#p/u/0/TBEPkgkWkTYhttp://www.youtube.com/user/sensecam#p/u/0/TBEPkgkWkTYhttp://www.youtube.com/watch?v=_SO1J1kP3YQhttp://www.youtube.com/watch?v=_SO1J1kP3YQhttp://www.youtube.com/watch?v=_SO1J1kP3YQhttp://www.youtube.com/watch?v=_SO1J1kP3YQhttp://www.youtube.com/user/sensecam#p/u/0/TBEPkgkWkTY


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Girton Labs 3D CAD design of PSOC scent badge, size 30mm diameter

Girton Labs has produced several 3D CAD designs and has the facilities to fabricate in many

materials including ABS, steel, silver, aluminium, ceramic, glass. These designs generally take about

2 hours to design, the files emailed to Shapeways in Eindhoven and a solid model delivered to Girton

Labs. This is an efficient use of time, very low cost method to design jewel enclosures rather than

hand building metal models.

Example of a 10 minute design for a sensing system, Girton Labs 2009

Below Rotating 3D sense model need Java plug in

The below Girton Labs SenseBadge Example shows a 3D model of an electronic frangrance system .

The multiple cartridge of fragrances is enclosed within the case. The computer selected multiple

fragrances are heated inside the chamber . After a few seconds of mixing in this chamber alivinghinge using Shapeways ABS printed 3D case , opens. It is opened by use ofFlexinolwire controlled

by the micocontroller. A single RGB LED lights up the enclosure to compliment the smell with an

appropriate colour, red is shown here. Here is avideo of inspiration of the living hinge, first created

in approximately the early 1960s. The living hinge should prevent the lingering effect of the smell.

A precise dose of fragrance can be delivered by measuring the temperature of the oven using a

thermopile. This can measure temperature within a few milliseconds unlike a thermocouple. It is

standard technology as used in modern microwave cooker for non contact tempwrature sensing.
http://en.wikipedia.org/wiki/Living_hingehttp://en.wikipedia.org/wiki/Living_hingehttp://en.wikipedia.org/wiki/Living_hingehttp://en.wikipedia.org/wiki/Living_hingehttp://en.wikipedia.org/wiki/Living_hingehttp://en.wikipedia.org/wiki/Living_hingehttp://www.dynalloy.com/AboutFlexinol.htmlhttp://www.dynalloy.com/AboutFlexinol.htmlhttp://www.dynalloy.com/AboutFlexinol.htmlhttp://www.youtube.com/watch?v=BzZK9naf9yohttp://www.youtube.com/watch?v=BzZK9naf9yohttp://www.youtube.com/watch?v=BzZK9naf9yohttp://www.youtube.com/watch?v=BzZK9naf9yohttp://www.dynalloy.com/AboutFlexinol.htmlhttp://en.wikipedia.org/wiki/Living_hingehttp://en.wikipedia.org/wiki/Living_hingehttp://www.shapeways.com/model/28188/cam6a.html?gid=ug


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The PSOC software design, mechanical 3D CAD and SenseBook, SenseBadge design was designed

and funded by Girton Labs Ltd and Associates and EEDA , Girton Labs own the IP rights.

The work of future Sensebadges etc is on going at present and will continue in 2012.

Project end

Lyndsay Williams choose to resign from UAL on Sept 25th 2010 due in part to financial issues with

CSM.


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