The USB Pumpkin in the Cloud

The USB Pumpkin in the Cloud

Getting into Halloween time, we thought it could be fun to show a Yocto-Color used within a pumpkin, and to use its RGB leds to change the pumpkin color. Nothing really special, actually. To make it a bit more challenging, we thought that it would look much better if we could have some kind of cloud floating around the pumpkin. Forget the small demo that we had originally planned, our pumpkin just bubbled into a big overkill...

OK, the pumpkin itself is ready, let's start the fun
OK, the pumpkin itself is ready, let's start the fun



It is pretty easy to create a small cloud of fog out of water: all you need is a small ultrasonic humidifier that vaporizes water into micro drops and rejects them as fog. You can find them in most wellness stores nowadays.

Our fog generator
Our fog generator



The only problem with this machine is that you need to fill in its tank from time to time, and none of us wanted to wake up in the night for that. So we have chosen to have the tank filled automatically, with computer-driven water level control. This was implemented using a small solenoid valve controlled using a Yocto-PowerRelay for water supply, and simple golden-plated pins dipping into the water to measure the water level. Since the resistance between two pins is significantly reduced as the water mounts around them, they behave more or less like a potentiometer. We can therefore use a Yocto-Knob to read the water level from USB.

In order to make it look real good, we built a small plastic piece to hold the solenoid valve and the golden-plated pins at the water entrance of the humidifier.

3D modeling of the piece to hold the solenoid valve and detection pins
3D modeling of the piece to hold the solenoid valve and detection pins



The same, after 3D printing with ABS plastic
The same, after 3D printing with ABS plastic



Automatic tank filling with computer-driven water level control, check.
Automatic tank filling with computer-driven water level control, check.



The whole think is monitored by a Delphi application, running on a low-power FitPC.

Carefully checking the system...
Carefully checking the system...



Trick or treat?
Trick or treat?



  



At the end of the story, we have a small cloud of fog, and a USB pumpkin in the cloud (or a cloud in the pumpkin, depends on the wind), the color of which can be remotely changed. And guess what? You can try it yourself!

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1 - alex_mass Sunday,october 23,2011 19H39

funky, la citrouille!
j'adore la démo interactive

Yoctopuce, get your stuff connected.