A warning pen lit up on bad food and poison gas
Especially in wars or attacks, nerve agent gas is used which does not have smell and color. In the same way, many food items emit gas vapors that we cannot smell even when they are spoiled. The pen has been developed by the Shenzhen Institute of Advanced Studies in China in collaboration with several institutions. The first prototype looks like a syringe and is very low cost and effective. It can also detect very small amounts of harmful chemicals due to its properties.