README.md

   1 # Code Club - Mini Band Project
   2
   3 <img src="http://farm9.staticflickr.com/8338/8256708023_4a941566e9.jpg" width="500" height="375" alt="photo (2)">
   4
   5 Make your own mini band!
   6 You and your friends can form your own finger-sized band and rock out using Raspberry Pi and Arduino.
   7 Learn how to build circuits with sensors and outputs and write a simple programme to control your instruments.
   8
   9 ## You will make:
  10
  11 * A guitar
  12 * A set of drums
  13 * A pair of maracas
  14
  15 ## You will need:
  16
  17 * 1 x Raspberry Pi (plus monitor and power supply)
  18 * USB hub
  19 * 2 x Arduino Uno boards (with USB cables)
  20 * 1 x strip potentiometer
  21 * 2 x tilt sensors
  22 * 4 x piezo buzzers (the type in greetings cards, easy to get from Maplin)
  23 * 10K resistors
  24 * Bread boards (1 per instrument)
  25 * Card
  26 * Sugru (or some other modelling material)
  27 * Electrical tape
  28 * Plastic drinking straw
  29 * Pencil
  30 * Coloured pens (optional)
  31
  32
  33 ## Software requirements:
  34
  35 * Scratch
  36 * IDE developer environment for Arduino
  37 * Py Serial library
  38
  39
  40 ## Useful links:
  41
  42 * [Pictures](http://bit.ly/codeclubminiband)
  43 * [Ardunio code](https://github.com/KatJoyWhite/miniband/tree/master/arduino)
  44
  45
  46
  47 ## Pull-down Resistors
  48
  49 You’ll find your analogue inputs receive signal when you don’t expect them to.
  50 This is because there’s electricty floating around in the system, or something like that.
  51
  52 To fix this, you need to wire each input to ground, through a 10KΩ resistor.
  53
  54 A better explanation can be found [here](http://arduino.cc/en/Tutorial/DigitalPins).
  55
  56
  57
  58 ## Drum Kit
  59
  60 <img src="http://farm9.staticflickr.com/8074/8257699966_7585ca06e7.jpg" width="375" height="500" alt="Code Club Miniband"><
  61
  62 ### 1. Make your drums
  63
  64 Take your 4 piezo buzzers and attach a ring of Sugru (or other modelling material) as shown in the picture.
  65 This will increase the flexibility and resonance of the sensors. Let the sugru set.
  66
  67 <img src="http://farm9.staticflickr.com/8353/8256628815_6c3872d3ac.jpg" width="500" height="375" alt="Code Club Miniband">
  68
  69
  70 ### 2. Connect the circuit
  71
  72 Piezo buzzers generate a small charges when you tap them, so they don’t need a power source.
  73 Connect one lead from your buzzer to one of your analogue inputs, and connect the other lead to ground.
  74 Repeat for each of your drums. It is easiest to use a bread board for making your circuit.
  75 Look at the picture for an example.
  76
  77 <img src="http://farm9.staticflickr.com/8081/8256628955_f65a76b6fb.jpg" width="500" height="375" alt="Code Club Miniband">
  78
  79 ### 3. Program the Arduino
  80
  81 Find the appropriate code from the respository and upload to your Ardunio board.
  82
  83
  84 ### 4. Set up in Scratch
  85
  86 Find four different drum sounds (or whatever sounds you'd like your drums to make!). Upload the sounds to Scratch.
  87
  88
  89 ## Guitar
  90
  91 <img src="http://farm9.staticflickr.com/8070/8257698984_8471e4cf57.jpg" width="500" height="375" alt="Code Club Miniband">
  92
  93 ### 1. Make your guitar
  94
  95 Grab your strip potentiomater, a piece of thin card, and a pencil.
  96 Lightly draw round your potentiometer on the card and then use this as a guide to draw out your guitar shape.
  97 (The potentiomater will be the fret board of your guitar).
  98 Cut out and colour in the guitar and stick down the potentiomater.
  99 Tape a pencil or stick to the back of the guitar to make it stiffen the fret board.
 100
 101 ### 2. Connect the circuit
 102
 103 The potentiomater strip adjusts resistance, so you will need to feed it some electricity.
 104 Run +5V into one of the strip’s outer pins, and ground into the other outer pin.
 105 It doesn’t matter which way around you connect these, but it will affect which the direction
 106 the fretboard runs (high and the top, low at the bottom or vice-versa).
 107
 108 Signal will come from the centre pin, so connect that to one of your analogue inputs and you should be good to go.
 109
 110 <img src="http://farm9.staticflickr.com/8363/8257699194_a2645e0e06.jpg" width="500" height="375" alt="Code Club Miniband">
 111
 112 ### 3. Program the Arduino
 113
 114 Find the appropriate code from the respository and upload to your Ardunio board.
 115
 116
 117 ### 4. Set up in Scratch
 118
 119 Find five different guitar sounds and upload to Scratch.
 120
 121
 122 ## Maracas
 123
 124 <img src="http://farm9.staticflickr.com/8346/8257698652_4a99ee24b4.jpg" width="500" height="375" alt="Code Club Miniband">
 125
 126 ### 1. Make your maracas
 127
 128 Cut 2 short lengths of drinking straw for your maraca handles.
 129 Using Sugru (or other modelling material), make 2 maraca heads by rolling it up into balls.
 130 Push the maraca heads onto the straws and mold into a maraca shape.
 131 Connect lengths of wire to the connectors of the 2 tilt sensors and then push each sensor into a straw until it presses into the Sugru.
 132 Leave the Sugru to set.
 133
 134 <img src="http://farm9.staticflickr.com/8222/8256627511_118192e52f.jpg" width="500" height="375" alt="Code Club Miniband">
 135
 136 ### 2. Connect the circuit
 137
 138 Connect the +5V port on the Arduino board to one of the pins on the tilt switch (it doesn't matter which way round).
 139 Connect the other pin to an empty digital input on the board.
 140
 141 <img src="http://farm9.staticflickr.com/8348/8257698572_4157db0b20.jpg" width="500" height="375" alt="Code Club Miniband">
 142
 143 ### 3. Program the Arduino
 144
 145 Find the appropriate code from the respository and upload to your Ardunio board.
 146
 147
 148 ### 4. Set up in Scratch
 149
 150 Find a maraca / shaker sound and upload to Scratch.
 151
 152
 153 ## Connecting to the Raspberry Pi
 154
 155 Set up your Raspberry Pi with a power supply and monitor.
 156 Connect all your Ardunio boards (it's easiest to have one per instrument!) to the Raspberry Pi using USB.
 157 You will probably need a USB hub.
 158
 159
 160 ## Python glueware
 161
 162 Download the music-maker-hander.py file from the repository. Run it with
 163     python music-maker-handler.py
 164 This program sets up a listener for each instrument. When it detects that an instrument has been played, it sends a couple of signals to Scratch.
 165
 166 The first signal appears in Scratch as a sensor value and is the volume (for drums), pitch (for the guitar), or ignored (for the maracas).
 167
 168 The second signal is a broadcast message that makes Scratch play the sound in the instrument.
 169
 170 One problem we had was with how the operating sytem mapped the various Arduinos to devices. It seemed to be pretty arbitrary. In the end, we tracked the device names by running
 171     tail -f /var/log/syslog
 172 in a separate terminal and watching what the devices were called when we plugged them in. We could then edit the various DEVICE parameters in to top of the Python script to fit. You could probably be cleverer by using some udev rules to fix the device names, but we didn't think of that (and didn't have enough time either).
 173
 174 ## Scratch front end
 175
 176 The Scratch file, music-maker, makes the sounds. It responds to the signals from the Python handler above by playing the appropriate sounds. It also does some visual feedback for the insturments.
 177
 178 Scratch on the Raspberry Pi is very slow, especially when it comes to updating the screen. Very often, Scratch would hang mid-way through a jamming session, only to start playing all the sounds after a short while. During the demos, people suggested that we minimise the Scratch window to reduce its workload.