Vision and audio are straightforward to digitize

.@maxhodak_ gives a fascinating explanation for why restoring smell with brain implants is much harder than fixing vision or hearing: Vision and audio are straightforward to digitize. We can already encode images as pixels and store audio as WAV files. But smell-o-vision would be far tougher to figure out. For years, companies have tried to create chemical detectors by growing neurons that express olfactory receptors - basically attempting to replicate a dog's nose, which are "some of the most sensitive chemical detectors in the universe." When dogs are trained to detect cancer, they're not picking up a single "cancer chemical." There are thousands of chemicals constantly leaking from your blood, and dogs learn to notice irregularities. The problem is you can't just mass spec smell. Smell is made up of thousands of compounds at once - and we still don’t have a file format for representing that complexity.