Over at 43 Folders, Gordon Meyer praises the Powerseed, a gadget designed to help you lose weight by flashing a little green light every 30 seconds (a signal to take a bite of food). He likes it as a general purpose mindfulness tool.
[W]hile it is marketed primarily for weight loss, it turns out to be a useful reminder/timer for virtually any activity where mindfulness is important. It's a sleek, battery-powered pod about as big as the end of your thumb. It offers both visual and audible queues, and operates in a couple of different coaching modes. The basic idea is that it is a discrete coach that prompts you to "check-in" with yourself. It signals both short and long regular intervals, which are useful for being aware of time passing, as well as performing different routines are each mark.
