In a serious case of out-of-the-box thinking, a design team at Roost in Sunnyvale California have come up with a method to add Wi-Fi connectivity to your old smoke or carbon monoxide alarm by just swapping batteries. Your smoke detector uses a 9 V PP3-type battery right? The new Roost battery contains 9 V lithium cells together with a processor and Wi-Fi chip in the standard PP3-sized battery outline. It monitors the battery voltage and power drain to alert you via Wi-Fi and a smartphone app when the alarm has been triggered, even if you are not at home.
It also prevents the annoying chirp that wakes you up in the dead of night to let you know the battery needs replacing. Falling air temperature during the night reduces the battery’s capacity so a marginal battery will fail the regular load test just as you are entering that deep sleep stage at about 3:00 am. The Roost battery is said to last more than 5 years and will send you a notification before its capacity falls to the point when the chirping begins. The battery is also suitable for mains powered units which have a back-up battery fitted.
The Roost team plan to fund the device with a kickstarter campaign in the near future and anticipate the battery will be shipping in the second quarter of 2015. Initial estimates of unit cost work out somewhere between $25 and $35.