555 Timer Ball Whacker

By Steve Hobley
Time Required: 1 hour

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[youtube http://youtu.be/VNmJG2f0NJA]

This project uses a simple 555 timer chip and a feedback loop to control a servo-controlled wooden arm. Whenever an object comes close to a photosensor mounted on the end of the arm, it blocks the amount of light detected, which triggers the arm to swat the object away.

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December 18, 2012, 10:43 pm PST

Parts

Parts

Servo motor, small RadioShack #273-765
Breadboard, small RadioShack #276-003
Resistor, 1/4W
Photoresistor RadioShack #276-1657
Diodes, 1N4148 RadioShack #276-1620
Desk lamp
Plywood, birch, 1/4"
Polystyrene ball or other lightweight, swappable object
Carriage bolt, 4"
Batteries, AAA (3) RadioShack #23-2214
555 timer IC RadioShack #276-1718
Electrolytic capacitor, 1.0uF
Electrolytic capacitor, 1000uF
Jewelers wire

Tools

Steps

Step #1: Create the Stand

NextPrev

I designed a simple frame to hold all the parts, cut from 1/4" birch plywood.
For this design, you can use a 4" carriage bolt across the top, from which gold wire and thread can be tied to suspend the "ball," in this case, a plastic egg.
Here's a simple template that can be used to cut out your own stand. Feel free to tweak it to your liking.

Conclusion

This project is a great example of a cybernetic, or "self-governing" system. These kinds of systems have been around since the steam age (check out fly-ball governors for an early example of the technology).

With this kind of analog robotic control system. remarkably human-like behaviour can be obtained without the need for complex digital programming.

Steve Hobley

This week, I have been mostly working on...

I've been tinkering around with bits of technology since I was five years old. I used to take the telephone apart at home, just to see how it worked.

After a couple of years I could even put it back together again - and sometimes it would continue to work.

10 Responses to 555 Timer Ball Whacker

Steve Hobley on July 5th, 2012 at 4:42 pm said:

I’m not familiar with a servo motor with only 2 wires. It would need power, signal and Gnd to function. Can you supply the make and model number?
Patricia Tsoiasue on November 6th, 2013 at 8:47 pm said:

This was a good project for a single afternoon with some kids. We used paint stirrers and an old piece of wood from my neighbor’s wood pile. Didn’t put the photo resistor onto the stick. I think we were so happy it worked… http://youtu.be/T78x7o4FvmY

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Make: Projects

Parts

Tools

Steps

Step #1: Create the Stand

Step #2: Populate the Breadboard

Step #3: Connect the Offboard Components

Step #4: Final Setup

Conclusion

Steve Hobley

10 Responses to 555 Timer Ball Whacker

Make: Projects

555 Timer Ball Whacker

Parts

Tools

Steps

Step #1: Create the Stand

Step #2: Populate the Breadboard

Step #3: Connect the Offboard Components

Step #4: Final Setup

Conclusion

Steve Hobley

10 Responses to 555 Timer Ball Whacker

Awesome!