sketch1 Toy Inventor’s Notebook — Root Beer Pong Bot

When making prototypes, I often “kit bash” broken toys to harvest useful components like motors, gear trains, or radio-control transmitters and receivers. No need to reinvent the wheel — literally!

SmartLab’s new toy robot, ReCon 6.0 Programmable Rover, is a tempting hack. Open it up and you’ll find lots of cool stuff inside, including a nifty dual-motor drive module with built-in optical wheel counters (go to for photos and details).

Here’s a “noninvasive hack” that takes advantage of ReCon’s cool features while adding a fun new function to make a “Root Beer Pong Bot.”

diagram1 Toy Inventor’s Notebook — Root Beer Pong Bot

I wanted to add a sensor to control ReCon in real time. Fortunately the toy’s nonvolatile memory retains your program even when the batteries are removed. So I used this feature to add a kill switch: a thin, double-sided contact that slips in between the batteries and ReCon’s battery contacts. This “power stealer” circuit works with a cup-mounted single-pole single-throw (SPST) micro lever switch that normally routes the power right back to ReCon — but if the switch is closed, power goes only to a bulb. When you toss a ball into the cup (à la Beer Pong), ReCon stops in its tracks and the bulb lights up — that’s a “kill.”

Next I created a simple program that turns ReCon into a moving target game.

As it follows a programmed path across the floor, it also plays a series of sound messages announcing an ever-decreasing point jackpot. The sooner you “kill” ReCon by tossing the ball into the cup, the higher your score! Go to for a listing of my program. You can also post your programs or other noninvasive hack ideas there.

And when you’re done with this noninvasive hack, just slip the wires out from the battery compartment, and your toy is back to original factory condition!

Bob Knetzger

Bob Knetzger

Bob Knetzger ([email protected]) is an inventor/designer with 30 years of experience making fun stuff.

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