Cars kill hundreds of dogs every year, even when they're parked.

The Dog Caller lets dog owners receive a text message alert if and when the temperature of their canine companion rises to unsafe levels

Leaving a dog alone in the car during the sweltering summer months is one of the more irresponsible things you can do as a pet owner, but a new heat-sensitive collar aims to help those with no other option keep tabs on their furry friends. Creative Directed, Tech Directed and developed while at Rethink Toronto in conjunction with the Humane Society, the Dog Caller built with Arduino, a thermistor, cellular shield and a SIM card, with the latter giving the collar the ability to send owners a text message alert if and when the temperature of their canine companion rises to unsafe levels — roughly 26 degrees Celsius (79°F).