This bracelet is modeled after my watch, which is my own invention. While you are wearing it, it will grow hot against your skin if you are about to eat or drink something that is spiked - with anything. It is also capable of neutralizing all common poisons and Veritaserum, at which point it will grow very cold when neutralization is successful.
However, there are any number of things that can be slipped into food and drink, so if it does not turn cold almost immediately, you should find a way to avoid ingesting whatever it is.
I hope you'll find it useful. My own version of it has saved my life, and likely my sanity as well, on numerous occasions.