Some projects are simply more fun than others. This secret knock gumball machine, designed by Steve
Hoefer, was such a project for me.
Click here to
see the gumball machine in action
Assembly of the electronic components was not easy for me.
The machine’s
actions are controlled by a tiny microprocessor called Arduino. The code for these operations was written by
Steve Hoefer and was easily downloadable from the internet. Not quite as easy was the assembly of the
circuit containing the sound sensor, the Led lights, and the servo mechanism.
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| Here is the wiring diagram. It looks simple but every wire and pin in the circuit required a solder joint. |
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This is what the bench looks like in the thick of
soldering. Here are some of my
problems. My hands shake. That is addressed by using a vise and small
clamps to hold things together. The
parts to be joined are small and hard to see.
That is addressed with the magnifying visor. Soldering is a skill and I have little experience. This, and all the other problems, are
addressed by actually working at it!
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Some of my solder joints: They are sloppy but they
work!
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The assembled circuit and the Arduino microprocessor ready
to be joined. The Piezo electric sensor
is the machine’s sense organ. The device
converts an electric current into a vibration (it buzzes) but it also converts
a vibration into an electric current. So, the
piezo device converts the "knock" into a series of electric pulses. The pulses are then evaluated by the microprocessor. If the knock is correct the microprocessor activates a servo
mechanism and a gumball is released.
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The electronic components are assembled and ready for
testing.
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| Adding the electronics to the case. |
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| Now, adding the "knock Board" with the piezo sensor attached. |
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| Voila! Ready to dispense gumballs! |
Click here for the "back Story".
Click here for cabinet construction.
