[favoritecolor]

Love seeing these types of posts on HN! Every now and then I see a post about olfaction, and since I am in the olfactory receptor research space, I just want to put my two cents out there.

Digital chemical sensing is hard, and yet biological chemical sensing is amazing. Understandably, there's always been immense interest in digitizing the biological process of smell. People have been pitching various technologies, from the early days of the WaspHound[0] and DARPA's largely failed RealNose project[1], to current efforts from startups[2] and big players in perfumery[3].

It is my opinion that all of these technologies are solving the wrong problem. Olfactory receptors are just plain horrible proteins. They're extremely difficult to produce, and even when you can express them, they have exactly the wrong type of properties. Each olfactory receptor responds to many different chemicals with really bad sensitivity. While that works really well for animals, these properties are a nightmare for digitization.

If we want to digitize chemical sensing, I believe we will need better proteins than naturally occurring olfactory receptors. And that's what I am trying to do currently in my Ph.D. research!

[0] https://en.wikipedia.org/wiki/Hymenoptera_training [1] https://www.defensedaily.com/darpa-awards-contracts-for-sens... [2] https://yesse.tech/ [3] https://www.firmenich.com/company/research

[tgbugs]

If you haven't read "What the fly’s nose tells the fly’s brain" [0] take a look. It helps explain why the olfactory sensors might actually be selected to have wide spectrum sensitivity (it's a feature not a bug).

0. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4522789/

[favoritecolor]

Thanks for the link! Cool to think about how the evolution of smell has optimized for "a maximum entropy code."

I totally agree, it's a feature not a bug. A wide spectrum is absolutely an essential feature for an animal to sense thousands (to millions) of different chemicals without thousands (to millions) of different receptors. So, calling olfactory receptors "just plain horrible proteins" was a bit rude to them, haha!

However, in my opinion, digital sensors based on olfactory receptors have and will continue to suffer from such wide spectra and poor sensitivities.