Friday, 1 March 2013

Low cost electronic scents and smells

Lavender bulb electronic scent designed by L Williams, size approx 10mm x 10mm 

I have been working on scent generation since 2008, initially  financed by a research grant from the UK's East of England Development Agency, for  a cookery book with embedded electronic smells,   From 2009 -2011 I did some of the electronic design  for Dr Jenny Tillotson of the University of the Arts, London.
 Motion is detected by touch (e.g. accelerometers ) which triggers the smell.

The scent, for example synthetic chocolate, is added using a solid scent under microcontroller software. This  is released by embedding the liquid  scent oil  in solid silicone and using a 1- 5W heater to release smell.  There has always been a challenge with computer controlled liquid scent release in making it leakproof,  compact for mobile phones, low battery power and with no lingering smell. Some liquid oils are toxic and need a solid enclosure.   However solid materials can be used to embedded the scent, technology as here from 2008  in silicone scented bulbs which use low cost silicone bath sealant.  Another example are scented silicone wristbands, the body heat releases scent.
 In this example, a  heater (nichrome wire embedded  inside the silicone) is switched on to release fragrance and a non contact thermopile temperature sensor with just milliseconds response time allows just  the correct amount of heat to be added to enable long battery life from a mobile phone battery. Nichrome heaters  have been used to emit scent from materials such as oils  for animal attractant  hunting activities.
 The scent is embedded in  liquid silicone rubber, which cures to a solid over several hours,  so no leakage or lingering smells as with liquid scents. The silicone is inert, and can be mixed with scented oils.  Custom shapes of silicone rubber can be created in a mould. One example is of  heater  resistor dipped in silicone rubber. The scent can be quickly terminated by the closure of a lid, e.g. closing a page in a book. A Flexinol Hinge can be used.

 Multiple scents can be mixed and proportional control of individual  scents added using the heaters with pulse width modulation in an x/y matrix arrangement to reduce cost. Alternative heating can be used e.g. Peltier heaters which can be switched from heating to chilling under software control to stop the odour release. Ultrasonic vibration  may be able to be used to release fragrance so no heat required, instant on/off  and longer battery life.

Apple iPhone with scent cartridge illustration

Prototype chocolate  heater
Lavender bulb, a LED can also be embedded

There are many possibilities for adding miniature scent emitters, e.g. in mobile phones. This will allows no visual or audio alerts to be sent, e.g. roses to your Mother, chocolate from your daughter   or coffee smell from your office. When the scent has expired, a new cartridge can be plugged in as illustration above with iPhone.  Medical applications e.g. sports,  relaxation and sleep devices can be built.
It was  found that embedding colour using  Red Green Blue mixer LED into the silicone aided the aesthetics. Tests are ongoing re adding  invisible UV LEDs.

3 Watt LED heaters from Philips,  can add colour,  Red, Green Blue and all colours of the spectrum, size of a coin

The silicone can be made into an ink and can be printed onto paper using screen printing. 


Some of my 2008  work on sensor triggered cookery scented books  as  here.

I  have worked for  Sensory Design and Technology Ltd, The University of the Arts, Central Saint Martins,  London and Northumbria  University 2009-2012 on computer control for scent research with Dr Jenny Tillotson and Prof Raymond Oliver.
2010 report on University of the Arts London research on scent generation. 

Here is a January 2011 patent on scent release from the University of Cambridge.

Contact Lyndsay Williams if you are interested in assistance with computer controlled scent designs. or +44 (0)  7970 101578.