Digital scent technology
Digital scent technology (or olfactory technology) is the engineering discipline dealing with olfactory representation. It is a technology to sense, transmit and receive scent-enabled digital media (such as web pages, video games, movies and music). This sensing part of this technology works by using olfactometers and electronic noses.
In the late 1950s, Hans Laube invented the Smell-O-Vision, a system which released odor during the projection of a film so that the viewer could "smell" what was happening in the movie. The Smell-O-Vision faced competition with AromaRama, a similar system invented by Charles Weiss that emitted scents through the air-conditioning system of a theater.  Variety dubbed the competition "the battle of the smellies". 
Smell-O-Vision did not work as intended. According to a Variety review of the mystery comedy film Scent of Mystery (1960), which featured the one and only use of Smell-O-Vision, aromas were released with a distracting hissing noise and audience members in the balcony complained that the scents reached them several seconds after the action was shown on the screen. In other parts of the theater, the odors were too faint, causing audience members to sniff loudly in an attempt to catch the scent. These technical problems were mostly corrected after the first few showings, but the poor word of mouth, in conjunction with generally negative reviews of the film itself, led to the decline of Smell-O-Vision.[ citation needed]
Since 1982,  research has been conducted to develop technologies, commonly referred to as electronic noses, that could detect and recognize odors and flavors. Application areas include food, medicine and the environment.
In 1999, DigiScents developed a computer peripheral device called iSmell, which was designed to emit a smell when a user visited a web site or opened an email. The device contained a cartridge with 128 "primary odors", which could be mixed to replicate natural and man-made odors. DigiScents had indexed thousands of common odors, which could be coded, digitized, and embedded into web pages or email.  After $20 million in investment, DigiScents was shut down in 2001 when it was unable to obtain the additional funding it required. 
In 2003, TriSenx (founded in 1999) launched a scent-generating device called Scent Dome, which by 2004 was tested by the UK internet service provider Telewest. This device was about the size of a teapot and could generate up to 60 different smells by releasing particles from one or more of 20 liquid-filled odor capsules. Computers fitted with a Scent Dome unit used software to recognize smell identifying codes embedded in an email or web page. 
In 2004, Tsuji Wellness and France Telecom developed a scent-generating device called Kaori Web, which comes with 6 different cartridges for different smells. The Japanese firm, K-Opticom, had placed special units of this device in their internet cafes and other venues until the end of the experiment on March 20, 2005.  Also in 2004, the Indian inventor Sandeep Gupta founded SAV Products, LLC and claimed to show a scent-generating device prototype at CES 2005. 
In 2005, researchers from the University of Huelva developed XML Smell, a protocol of XML that can transmit smells. The researchers also developed a scent-generating device and worked on miniaturising its size.  Also in 2005, Thanko launched P@D Aroma Generator, a USB device that comes with 3 different cartridges for different smells. 
During ThinkNext 2010, the Israeli company Scentcom featured a demo of its scent-generating device. 
In June 2011, a press release from the University of California, San Diego Jacobs School of Engineering  announced a paper published in Angewandte Chemie  describing an optimization and miniaturization of a component that can select and release scents from 10,000 odors, that is intended to be part of a Digital scent solution for TVs and phones.
In October 2012, Aromajoin, a Japanese company, released a small-sized product named Aroma Shooter which contains 6 different solid-type scents. 
In March 2013, a group of Japanese researchers unveiled a prototype invention they dubbed a " smelling screen". The device combines a digital display with four small fans that direct an emitted odor to a specific spot on the screen. The fans operate at a very low speed, making it difficult for the user to perceive airflow; instead they perceive the smell as coming directly out of the screen and object displayed at that location. 
In July 2013, Raul Porcar (Spain), engineer and inventor developed and patented Olorama Technology, a wireless system with the aim to incorporate scents into movies, Virtual Reality, and all kind of audiovisual experiences.: 
In December 2013 Amos Porat inventor and CTO Of scent2you Israel Company has built several prototypes that can control scents. 
In 2016 Surina Hariri, Nur Ain Mustafa, Kasun Karunanayaka and Adrian David Cheok from Imagineering Institute, Iskandar Puteri, Malaysia experimented with Electrical stimulation of olfactory receptors. 
At CEATEC 2016, Aromajoin unveiled the first wearable scent device, Aroma Shooter Mini, which can be connected and controlled from PCs and smartphones. Besides, the company also introduced a demo scent-enabled chatting app named AromaMessage in the event.  
In 2020 OVR Technology introduced their Architecture of Scent® Platform. Which includes the ION™ Scent Device which attaches to an AR or VR Headset, a software suite including a plug-in for content developers to add scent triggers and geometries to Virtual Reality objects, and their in-house developed Scentware.™ The combination of this Hardware, Software, Scentware platform delivers precise scent molecules based on the user's interactions and can help deliver improved immersion and presence for virtual reality training and wellness applications. The Architecture of Scent platform helps tackle most of the "current challenges" listed in the next section 
Current obstacles of mainstream adoption include the timing and distribution of scents, a fundamental understanding of human olfactory perception, the health dangers of synthetic odours, and other hurdles.
- Bosley crowther (December 10, 1959). "Movie Review: Behind the Great Wall (1959) - Smells of China; 'Behind Great Wall' Uses AromaRama". The New York Times. Retrieved 23 September 2012.
- Gilbert, Avery (2008). Hollywood Psychophysics" What the Nose Knows. Crown Publishers. p. 159. ISBN 978-1-4000-8234-6.
- Persaud, Krishna; Dodd, George (1982). "Analysis of discrimination mechanisms in the mammalian olfactory system using a model nose". Nature. 299 (5881): 352–5. Bibcode: 1982Natur.299..352P. doi: 10.1038/299352a0. PMID 7110356. S2CID 4350740.
- Martin, James A (1999-10-13). "Sniff That Web Site". PC World. Archived from the original on 2007-01-15. Retrieved 2007-07-06.
- "Digiscents runs out of cents". internetretailer.com. 31 May 2001.
- "Aroma Jet". www.microfab.com. Retrieved 10 December 2016.
- "Smelly device would liven up web browsing". New Scientist. 2004-02-20.
- "These images STINK. Really". esato.com. Archived from the original on 2011-07-23.
- "Gaming Smells - It's a Fact". MegaGames. 2004-12-30.
- "XML Smell language developed by university". The Inquirer. 2005-01-23.
- "Thanko USB P@D Aroma Generator".
- "3D TV with Touch, Smell by 2020?". betanews.com.
- "ThinkNext 2010 – Scentcom". www.geektime.co.il. 16 April 2010.
- Hockmuth, Catherine. "Coming to TV Screens of the Future: a Sense of Smell". UC San Diego Jacobs School of Engineering. UC San Diego. Retrieved 2 April 2013.
- Kim, Hyunsu; et al. (14 June 2011). "An X–Y Addressable Matrix Odor-Releasing System Using an On–Off Switchable Device". Angewandte Chemie. 50 (30): 6771–6775. doi: 10.1002/anie.201102759. PMID 21674743.
- Karen Bremer Masuda (November 13, 2012). "Smell-o-Vision for the Digital Age: Japan Develops USB "Micro Aroma Shooter"". Soranews24.
- Amanda Kooser (April 2, 2013). "Japanese scientists create 'Smell-O-Vision' screen". CNET. Retrieved April 3, 2013.
- Porcar, Raul (July 3, 2013). "Olorama incorporate scents into audiovisual experiences". DigitalAV Magazine.
- Shamah, David (December 20, 2013). "Scent2You hopes to bring 'Smell-O-Vision' to your tablet". Times of Israel.
- Strickl, Derek (11 March 2015). "FeelReal Brings Sense of Smell To Virtual Reality". /vrworld.com.
- Hariri, Surina (16 November 2016). "Electrical stimulation of olfactory receptors for digitizing smell". Proceedings of the 2016 workshop on Multimodal Virtual and Augmented Reality - MVAR '16. dl.acm.org/. Mvar '16. pp. 4:1–4:4. doi: 10.1145/3001959.3001964. ISBN 9781450345590.
- Tyler Lee (October 5, 2016). "Aromajoin Unveils The New Aromajoin Mini & Smartphone App". Retrieved October 30, 2018.
- "CEATEC JAPAN 2016 ( Official Website )".
- "OVR Technology's Architecture of Scent Press Release".