It’s a fantasy many a parent might have: monitoring their children as they safely made their way to the bus stop while they themselves sat comfortably with a steaming mug of coffee in front of their computer clicking between surveillance footage and catching up on the morning news.
Paul Wallich dreamt this last winter when he would walk with his elementary school-age son 400 meters downhill to wait for school pick up (don’t forget dad had to walk back uphill too). Unlike most parents though, Wallich had a concrete vision for how this dream could become a reality, and he put it into action.
Enter the “DIY kid-tracking drone.”
Wallich, a writer for the tech publication IEEE Spectrum, wrote in a post that he began his project with a quadrotor kit, which he outfitted with a system complete with the appropriate sensors that would allow it to follow his son autonomously. Instead of using a “fancy video transmission rig” to capture real-time footage, Wallich said that he hooked up his smartphone and used a video chat app.
“Getting the quadcopter built and into the air was almost too easy,” he wrote. “The hard part was getting it to locate and track its quarry.”
Wallich overcame this hurdle by implanting a GPS beacon in his son’s backpack. Here’s how he did it:
You can easily program the modem to transmit a GPS position to the copter only when the beacon has moved, and to go to sleep (and send the GPS chip to sleep too) when the beacon hasn’t moved for a few minutes. It makes for a smaller beacon—mine is about the size of a large thumb—powered by a coin-cell battery. Depending on your target’s movement patterns, a single coin cell might last for a week.
Overall, Wallich has found his system still needs some tweaks. The quadrotor isn’t quite reliable enough on windy days and there are times when his vision is obscured by treetops. He said the drone’s battery life — a 2200-milliampere-hour lithium-ion battery — is a hindrance as well, only giving him enough juice to fly to the bus stop, hover, and turn back.
Therefore, until more improvements are made, he’ll be braving the winter weather with his son on foot this year.
Wallich provides far more details about the equipment and how he put it together. Check out his full article to read more on it here.