Researchers at The University of Texas at Austin have designed a way to sense dangerous chemicals using, in part, a simple rig consisting of a smartphone and a box made from Lego bricks, which could help first responders and scientists in the field identify deadly and difficult-to-detect nerve agents such as VX and sarin. The new methodology described in a paper published Wednesday in the open-access journal ACS Central Science combines a chemical sensor with photography to detect and identify different nerve agents—odorless, tasteless chemical weapons that can cause severe illness and death, sometimes within minutes.