28 Nov

Minions Operation – Finished!

The Minions Operation with Minions audio samples is finally finished. Finishing a project completely (like making enclosures and making sure things are nicely finished) is really time consuming. Still, its done now and in time for Christmas. Hopefully the Nieces and Nephews will find it amusing because I have endured hours of Minions samples doing this…

So i’ve gone from this:


To this:


With the electronics tucked neatly away in the 3d printed orange box.

And from the other side:


Lid off, electronics exposed. Holes drilled for speaker which was glued in place with epoxy.


Electronics up close:


I’ve replaced the original light bulb with an LED (fore ground), the motor with a mobile phone buzzer motor (the little metal disk with the black top, middle left), a prototyping board with the Arduino Pro clone (middle) and WT588D audio board (top) and some resistors, a transistor, diode and cap.

Originally I had intended to use the buzzer motor that came with the game. It all worked perfectly when running from a power supply but as soon as I tried to run it all from 3 x AA batteries, the Arduino would reset as soon as the motor was triggered.

Testing the electronics worked (little green speaker was too quiet and was replaced with 0.5w 8ohm speaker):


I added the capacitor to try and smooth out the current, but it wasn’t enough. I tried reducing the current through the transistor by increasing the resistance of the resistors feeding the transistor base, but that didn’t work until the resistance was enough to stop the motor powering up. In the end I swapped the original buzzer for a tiny version from a mobile phone (these can be found for less than a quid on ebay) and that worked happily from battery power.

More recently I have had problems with the WT588D not working after power on. It takes a few power-off/power-on attempts before it will start playing samples. The Arduino is working because the buzzer and the LED work. I plan to add a power on delay and then play a sample to confirm it is working. It should be possible to have the Arduino detect if a sample is playing by reading the ‘busy’ signal from the WT588D and resetting it if not detected during a startup routine.

Code is available from github

Last Updated on 28 November 2015 by Mark