1 # Code Club - Mini Band Project
3 <img src="http://farm9.staticflickr.com/8338/8256708023_4a941566e9.jpg" width="500" height="375" alt="photo (2)">
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.
17 * 1 x Raspberry Pi (plus monitor and power supply)
19 * 2 x Arduino Uno boards (with USB cables)
20 * 1 x strip potentiometer
22 * 4 x piezo buzzers (the type in greetings cards, easy to get from Maplin)
24 * Bread boards (1 per instrument)
26 * Sugru (or some other modelling material)
28 * Plastic drinking straw
30 * Coloured pens (optional)
33 ## Software requirements:
36 * IDE developer environment for Arduino
42 * [Pictures](http://bit.ly/codeclubminiband)
43 * [Ardunio code](https://github.com/KatJoyWhite/miniband/tree/master/arduino)
47 ## Pull-down Resistors
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.
52 To fix this, you need to wire each input to ground, through a 10KΩ resistor.
54 A better explanation can be found [here](http://arduino.cc/en/Tutorial/DigitalPins).
60 <img src="http://farm9.staticflickr.com/8074/8257699966_7585ca06e7.jpg" width="375" height="500" alt="Code Club Miniband"><
62 ### 1. Make your drums
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.
67 <img src="http://farm9.staticflickr.com/8353/8256628815_6c3872d3ac.jpg" width="500" height="375" alt="Code Club Miniband">
70 ### 2. Connect the circuit
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.
77 <img src="http://farm9.staticflickr.com/8081/8256628955_f65a76b6fb.jpg" width="500" height="375" alt="Code Club Miniband">
79 ### 3. Program the Arduino
81 Find the appropriate code from the respository and upload to your Ardunio board.
84 ### 4. Set up in Scratch
86 Find four different drum sounds (or whatever sounds you'd like your drums to make!). Upload the sounds to Scratch.
91 <img src="http://farm9.staticflickr.com/8070/8257698984_8471e4cf57.jpg" width="500" height="375" alt="Code Club Miniband">
93 ### 1. Make your guitar
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.
101 ### 2. Connect the circuit
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).
108 Signal will come from the centre pin, so connect that to one of your analogue inputs and you should be good to go.
110 <img src="http://farm9.staticflickr.com/8363/8257699194_a2645e0e06.jpg" width="500" height="375" alt="Code Club Miniband">
112 ### 3. Program the Arduino
114 Find the appropriate code from the respository and upload to your Ardunio board.
117 ### 4. Set up in Scratch
119 Find five different guitar sounds and upload to Scratch.
124 <img src="http://farm9.staticflickr.com/8346/8257698652_4a99ee24b4.jpg" width="500" height="375" alt="Code Club Miniband">
126 ### 1. Make your maracas
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.
134 <img src="http://farm9.staticflickr.com/8222/8256627511_118192e52f.jpg" width="500" height="375" alt="Code Club Miniband">
136 ### 2. Connect the circuit
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.
141 <img src="http://farm9.staticflickr.com/8348/8257698572_4157db0b20.jpg" width="500" height="375" alt="Code Club Miniband">
143 ### 3. Program the Arduino
145 Find the appropriate code from the respository and upload to your Ardunio board.
148 ### 4. Set up in Scratch
150 Find a maraca / shaker sound and upload to Scratch.
153 ## Connecting to the Raspberry Pi
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.
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.
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).
168 The second signal is a broadcast message that makes Scratch play the sound in the instrument.
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).
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.
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.