I recently build a popcorn controlled drum set! While making popcorn some time ago, and experoiencing the strength with which the popcorns explode, I started to think in which ways I could use that. Maybe popcorn triggered toy car? I then thought I would do a popcorn triggered houshold orchestra. But finally I attached the popcorn to a drumset. So this is how it works:

The popping of the popcorn triggers 12 piezo contact microfons, which are hard wired to a an Arduino Mega and converted to MIDI Signal. This MIDI Signal goes to our custom-made robotic drum System, which plays the drums.

You could also just connect the MIDI output to a synth and play around with randomly created

SHOPPING LIST

// WRITTEN FOR ARDUNIO MEGA (2560)
// For Use with Arduino Uno, use “Serial” to send the Midi Notes (instead of “Serial1”)
// and delete the lines of code that send Values to the Console for Debugging [Lines 89-90, 107-111]// The Number ob Pads also has to be reduced to the UNOs 8 Analog-In-Ports (7 With Sensitivity Poti) [Lines 20, 21, 53, 88]

unsigned char PadNote[16] = {36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51};
int PadCutOff = 30; // Minimum Value for a triggered Note
int MaxPlayTime = 150; // Cycles before a 2nd hit is allowed
#define midichannel 0; // MIDI channel. (0-15)

boolean activePad[15] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; // Array of flags of pad currently playing
int PinPlayTime[15] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; // Counter since pad started to play

unsigned char status;

int pin = 0;
int hitavg = 0;

void setup()
{
Serial.begin(115200); // connect to the serial port 115200 for Serial Monitor
Serial1.begin(31250); //connect to the second serial port for MIDI out
pinMode(LED_BUILTIN, OUTPUT);

pinMode(7, OUTPUT); //GND Poti Sensitivity
pinMode(6, OUTPUT); //VCC Poti Sensitivity

digitalWrite(7, LOW);
digitalWrite(6, HIGH);
}

void loop()
{
for(int pin=0; pin < 15; pin++) { hitavg = analogRead(pin); // read the Voltage from the Piezo if((hitavg > PadCutOff))
{
if((activePad[pin] == false))
{

hitavg = 127; // Velocity to play the Note with

MIDI_TX(144,PadNote[pin],hitavg);
digitalWrite(LED_BUILTIN, HIGH); // Lets the builtin LED blink every time a note is triggered
PinPlayTime[pin] = 0;
activePad[pin] = true;
}
else
{
PinPlayTime[pin] = PinPlayTime[pin] + 1;
}
}
else if((activePad[pin] == true))
{
PinPlayTime[pin] = PinPlayTime[pin] + 1;

if(PinPlayTime[pin] > MaxPlayTime)
{
activePad[pin] = false;
MIDI_TX(128,PadNote[pin],127); // Call Send-Midi-Note Routine
digitalWrite(LED_BUILTIN, LOW);

}
}
}

PadCutOff = analogRead(15); // reading the Voltage from the Poti for Sensitivity
Serial.print(PadCutOff);
Serial.print(“\n”);
}
void MIDI_TX(unsigned char MESSAGE, unsigned char PITCH, unsigned char VELOCITY)
{

status = MESSAGE + midichannel; //Sending triggered Notes via Midi
Serial1.write(status);
Serial1.write(PITCH);
Serial1.write(VELOCITY);

Serial.print(“Triggered note “); //Sending triggered Notes user-readable via Serial for Debugging
Serial.print(PITCH);
Serial.print(” with Velocity “);
Serial.print(VELOCITY);
Serial.print(“\n”);

}

You don’t own a haunted castle but still want that Scottish chic of a “ghost chateau”? Make your own ancestors portray with automatic moving eyes and easily scare away unwanted guests!

We all know that old movies, where the young couple is staying in the haunted castle for the first night and gets scared away by pictures of some beardy ancestors, where the eyes seem to follow the spectators. In the end its just the butler who is spying from behind to get the heritage … but anyway. So you want to build one of these pictures, too. It’s not hard!

Before you start

• Time: 6-8h building time + time for the stuff you order online to arrive (days!)
• Level: Mid. A little programming, soldering and general handcrafting skills required
• You need: standard Tools (cutter, drill, screw driver),
• Arduino Uno,
• Standard Servo Motors from Futuba or Hitec e.g. this
  one,
• Hot Glue,
• Wire,
• Frames with old pictures (see below),

Preparations

First you need a picture of your loved (or hated) one. A good portray in a high resolution (> 2MB in size) is recommended. Some photoshop magic later you have the picture with a custom background you find in the Internet. Put it into an online oil painting generator to create an even more old school look.

Now you need one or two framed pictures from the flee market.

Cut away the original background – maybe you can reuse it if its hard wooden sheet. In other cases cut some fresh wooden sheet of 2-5mm thickness.

Measure the frame and rezise the digital portray accordingly. We printed the photos out on A1, 230g/cm linen structure paper as a digital print (in europe yuo can use flyeralarm).

Start making

When the prints come from the printing service you can start making! We reused the background from the original frame picture we got from the flee market, but you can use any type of (wodden) material thats fits in the frame. We recommend a thickness of 2-6mm.
Now its time to cut the shape of the print as well as the eyeballs of your loved or hated on. A wonderful job, plus you have spare eyeballs now!

Now mark on the wooden background where the eyes are sitting. Now you need eyes. Its not so easy to get decent eyeballs in the Internet (we haven’t checked the dark web though), so you are very lucky, because we prepared some for you! You can find a print ready A4-pdf with fitting eyeballs here. Adjust the size when you have a bigger / smaller image and print them out on A4.

Take your background wood and mark where eyes will go. Measure it with the eyeballs you arleady have. Cut out a square as in the picture below.

Glue the eyes to the remaining wood you just cut out (which you made a little smaller on both small sides so it can move!)

We then used spray glue to glue the portrait to the background.

Electronics

Now you start with the electronics. You need a servo motor like this one.

We had a 3D-printer so we could print a holder. You can find the STL files in the github repo below. If you don’t have acess to a printer or use another type, we recommend building something similar from wood. The following steps are how we did it with our setup. It will probably differ if you want to rebuild this. Use your imagination and handcrafting skills to replicated the functions.

Time to build the mechanical part! We used a brass tube (4mm) which is screwed on the servo motor as an arm. This holds a 1mm acrylic thread. connected to the eyes-square.

On the eyes-sqaure we used an holder (the black one) and a terminal thread to hold the acrylic thread and a rubber band.

The moving eye-square is on the one side connected to the moving servo motor. The other side is fixed with a rubber band, so it gets drawn back if the servo releases. Be sure to put some wood over the backside so the eyes can still move, but also don’t fall out to the back!

Now, wire and program the arduino with the code oftware you can find in the Github repository below. A description of how the servo(s) are wired can be found in the code. We used a 12V / 2A wall plug to power the whole thing.

You are done! Ready to get haunted!

Resources

• Arduino Code at github
• PDF with eyeballs (pdf)
• online oil painting generator
• 3D Printed Servo holder