Sunday, 2 November 2014

Halloween ghost


Here we go, Halloween has arrived and I have to make something for it! Below you can find my first sketch that I have done in a pub ( and in the end of this post, something that should look like that).
In few words, what I wanted to create was a simple ghost that will interact with people by walking close to it.
The interaction should be an inflatable arms and flashing eyes & mouth.

- Few yellow leds
- Few red leds
- Few transistor
- Ghost cover ( bought one from poundland shop )
- Few shopping bags that match the color of your ghost
- Two powerful fans
- A lot of batteries :)

Making arms

The inflating of arms was something tricky to achieve, because I had to find a good material and very light.
By hot glueing a shopping bag around the fan and make a relative small tube, I managed to inflate two arms.
I was using a very powerful fan with double prop and  6 batteries to get 9 volts.

Flashing leds
My flashing system was made with 2 transistor and few leds.
I used one transistor to flash the eyes ( red leds ) and the second one to flash the mouth ( yellow leds ). I have avoided to use a 5 volt regulator and connected  everything into the Arduino.
You should be careful to use this method, because your Arduino might shut down due too much current drained from the leds. I was lucky and my Arduino didnt shut down :)

One issue that I found while the ghost was working at the party, was some interference with the IR sensor, probably due to colored lights or else.
One solution would be to use a sonar sensor instead.

Arduino was shutting down after the fans were on. This happened because my fans were draining too much power and the arduino lost power and reset itself.
One solution would be to solder a bigger capacitor, so the Arduino would run for the short drop of power.
Second solution, the one that I chose because I had a spare battery hold, was to use another power source to power the Arduino. You could try with a 9V battery or just 4 batteries holder.

Images and videos