furious said:
Michael V said:
Cymek said:
In the current season of Westworld one of the characters has a t-shirt than lights up one of the below emotions when they are feeling it.
It’s never mentioned how it works he is just wearing it.
How would one work do you think, sensors on the inside that detect hormones from swear perhaps

Heat-sensitive dyes.
In the 1990s I bought a coffee mug at Yosemite that changed colours when it was hot.
Hypercolor
“Hypercolor was a line of clothing, mainly T-shirts and shorts, that changed color with heat.”
“Substances that can change color due to a change in temperature are called thermochromes. There are two known types of thermochromes: liquid crystals (used in mood rings) and leuco dyes (used in Hypercolor T-shirts).
“The color change of Hypercolor shirts is based on combination of two colors: the color of the dyed fabric, which remained constant, and the color of the thermochromic dye. Droplets of the thermochromic dye mixture are enclosed in transparent microcapsules, a few micrometers in diameter, bound to the fibers of the fabric.
“The thermochromic droplets are actually a mixture of several chemicals—crystal violet lactone (the color-changing dye itself), benzotriazole (a weak acid), and a quaternary ammonium salt of a fatty acid (myristylammonium oleate) dissolved in 1-dodecanol as solvent. Together, these lead to a reversible chemical reaction in response to temperature change that produces a change of color.
“At low temperatures, the mixture is a solid. The weak acid forms a colored complex with the leuco dye by causing the lactone ring in the center of the dye molecule to open. At high temperatures, above 24–27 °C, the solvent melts and the ammonium salt dissociates, allowing it to react with the weak acid. This reaction increases the pH, which leads to closing of the lactone ring of the dye to convert it to its colorless (leuco) form.
“Therefore, at the low temperature the color of the shirt is the combination of the color of the encapsulated colored dye with the color of the dyed fabric, while at higher temperatures the capsules become colorless and the color of the fabric prevails.”
Mood rings are fun. Miss m bought one only a couple of years ago. It changed colour properly.
I once had a thermometer with thermochromic dyes that lit up as the temperature changed. It was awful, it hardly if ever lit up bright enough to see.