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.

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.”

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!

Code Sheet

Here’s the code sheet for the game program I wrote. Each numbered box is a step in ReCon’s instructions. ReCon beeps, announces the game and 10 points, turns around (so that he presents the cup to you), backs up, stops to announce 75 points, turns and backs up, turns and backs up again, stops and announces 50 points, turns and backs twice again, then if you haven’t yet gotten the ball in the cap and triggered the kill switch, Recon blows his horn and announces you lost, as he does a victory dance to a dance beat.

What kind of game program can you create? Can you use the LOOP command and HOME command to make a more elegant routine?

More Photos

A close up of the battery compartment. Note the two wires with a thin insulator between them at the lower right. The red wire steals the power from the batteries, send it to the outboard switch, which either sends it right back via the green wire, or sends it to the external bulb.

Here’s the cup with the micro switch mounted in the bottom. A round paddle is glued to the arm of the switch.

The ReCon robot executes its mission. It trucks along a programmed path of runs and turns, announcing the decreasing point value as it goes.

The weight of the ball trips the switch, cutting off power to the ReCon which stops in its tracks, and also illuminates the “kill” bulb. Your score is the last point amount ReCon announced. Remove the ball and play again. ReCon’s non–volatile memory keeps your program!

If you do open up and invasively hack a ReCon inside you’ll find a really cool module with twin geared motor drives, each with interrupt wheels and opto emitters/detectors for counting partial rotations. What else could you make with this?

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!

Toy Inventor’s Notebook — Root Beer Pong Bot

By Bob Knetzger