At 30 feet tall, the Colossal Robotic Hand is one of the Science Mill’s most iconic exhibits. Already impressive for its super-sized scale, what makes the Hand so memorable is that you get to control its position—whether that’s a titanic thumbs-up or a humongous “Hook ‘em Horns.” After a few months offline, the Colossal Robotic Hand is back in action for Winter Break with a new and improved controller, thanks to a helping hand from the Mill’s exhibit engineers.

The new controller features nine sliders: one for the thumb and two for each finger, controlling its top and bottom “joints.” Each slider is part of a potentiometer, a device that varies resistance to change the voltage in an electrical circuit. (If you’ve ever adjusted a volume knob or used a dimmer switch on a light, you’ve most likely put a potentiometer to work.) The changing voltage is read by an Arduino microprocessor, which translates it into digital data about the position of that finger. Then the Arduino in the controller syncs up with an Arduino in the Colossal Robotic Hand to share the info. Once you press “Go,” the Hand’s Arduino tells linear actuators how to move the fingers and—ta-da!—a 30-foot peace sign.

The coolest part about the new controller? It’s built from layers of clear acrylic, so you can see all the circuits and components inside!

A behind-the-scenes look at the controller being created: Following a digital pattern, a laser precision cuts a sheet of clear acrylic, including holes for wiring and for screwing together the final “sandwich” of tech components and acrylic panels.

High-Five Facts about the Colossal Robotic Hand

1. The Colossal Robotic Hand was designed and constructed at the Science Mill from 500 stainless steel triangles. It took over 1,000 feet of welds to assemble everything – imagine welding from end-zone to end-zone of a football field three times!

2. To safely anchor and bear the Hand’s weight, we had to dig an 8-foot-deep foundation. A crane carefully stacked the Hand, piece by piece, into place.

3. We programmed the fingers to move in a certain sequence to keep them from bumping into each other. The Arduino inside the Hand not only receives info on where to move the fingers, but also keeps track of each finger’s current position to avoid collisions. For instance, it knows not to move the fingers first if the thumb is in the way or vice versa.

4. We also programmed the hand to be polite: it can’t make any rude gestures!

5. The Arduino microprocessors that control the Hand are inexpensive and user friendly—if you’re interested in exploring programming at home, definitely check them out.

MORE TO EXPLORE

• You’ll find the Colossal Robotic Hand in our Science & Art Park, alongside other awesome feats of engineering by the Science Mill team—like the Incredible Ball Machine and the Wave Pendulum. You’ll also find works by acclaimed Texas artists that blend art and science: Voice Over by Riley Robinson and the Silo of McKays by McKay Otto.

• In Explorer Zone Episode 6: The Colossal Robotic Hand, go behind the scenes to see how the Hand was built and find biomechanics and robotics activities to try at home, including a DIY robotic hand!

• Try your hand at coding and robotics at Homeschool Days: Careers in Coding on Thursday, Dec. 16 from 10am-2pm. All young programmers are welcome, including those in learning pods or with asynchronous school schedules.