Researchers from Carnegie Mellon University have come up with yet another use for old phones that's quite practical. It's a program called Zensors and as Gizmodo explains, it enables connected smartphones (and surveillance cameras) to monitor the environment they're viewing through the lens, analyze it and report back with valuable information.

In the clip above, the team demonstrates how easy it is to repurpose an old phone as a surveillance device that can provide feedback (in this example, asking how many cars are in a parking lot). Users can set up how often the logic question is asked and the program will handle the rest and provide you with the answer.

That sounds really impressive for software, right? The reality is that some complex Zensors tasks are crowd-sourced (similar to Amazon's Mechanical Turks) while easier duties are indeed handled by algorithms. Over time, the team hopes the software will be able to take on tougher tasks.

Zensors is still in beta at the moment but we're keeping our fingers crossed that this will one day be available to all.

In the meantime, there are several options for old smartphones past their prime. If you can't get enough money from eBay, Craigslist or buyback programs, perhaps it might make a good phone for a youngster, a friend in need or a relative that doesn't care about having the latest and greatest. And if keeping it as a backup isn't an option, there are plenty of companies that offer environmentally-friendly recycling methods.