Where the Hackaday Cat goes when she steps over the threshold into the wider world is a mystery, she reveals her whereabouts strictly on her terms and would we suspect be very cagey were we able to ask her about it. [Andy C] however has a need to know where his cat is spending her time, so he’s made a GPS collar for a bit of feline spying.
There are commercial GPS collars for pets, but they all share the flaw of extremely limited battery life. His challenge then was to create a collar that delivered the required pinpoint fix alongside a battery life measured in months. The solution was a combination of a low-power miniature GPS receiver and a low-power PC microcontroller hooked up to an FSK radio whose frequency he doesn’t give but which we suspect is probably the usual 433 MHz. The collar remains in low power mode until it receives a call on the FSK, at which point it wakes up, gets a GPS fix, transmits it, and returns to sleep.
The summary links to a series of posts which provide an extremely detailed look at all aspects of the project, and go well beyond mere GPS trackers for a cat. If you have an interest in low power devices or antenna matching for example, you’ll find a lot of interesting stuff in these pages. Of course, if all you need is a GPS tracker though, you may prefer a simpler option.