The Official Raspberry Pi Projects Book - Projects_Book_v4

Tutorial

raspberrypi.org/magpi The Official Raspberry Pi Projects Book 135

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Figure 2 The full set

of controls on the DJ

Hero controller

Turntable – adjust parameter

Just pattern Full screen & Reset name

Redraw

Invert screen Select parameter to edit

Rotary – not used

Redraw depth Harmonic control Amplitude – Phase

Amplitude – Frequency

Damping

MAKE SCRATCH ART

extension wires to it, or get a small ‘Wii Nunchuk
adapter’ PCB and wire that to the Pi. Figure 1 shows
the wiring you need; as there are only four wires, you
can use a length of ribbon cable to attach it to the Pi,
with the cover neatly clipping over the top.

Language

>PYTHON 2

DOWNLOAD

THE CODE:

magpi.cc/1NqJjmV

PROJECT

VIDEOS

Check out Mike’s

Bakery videos at:

magpi.cc/1NqJnTz

Nunchuck

Adapter

+3V3 Gnd

Data I

(^2) C
GPIO 2
Clock I
(^2) C
GPIO 3
Figure 1 Wiring the Wii Nunchuk adapter to the Pi
Talking to the DJ Hero
The DJ Hero comprises a collection of buttons, knobs, a
joystick, and a turntable. Figure 2 shows these controls
labelled up as the functions they’re going to perform in
this project. The I^2 C address of this device is 0x52 and
consists of a number of registers. To initialise the device
on power-up, you must write the value 0x55 to register
0xF0. Note that each successive read will increment
the address of the register read from. So, to read the
interface status, you need to set the register to zero and
then read data six times – these six bytes contain the
information from the DJ deck. The assignment of bits is
shown in Figure 3 overleaf, and at first sight looks a bit
complex. Kowever, this diagram has been simplified, in
that the DJ Hero is capable of having a second turntable
on the left-hand side, and the bits corresponding to this
second turntable have been omitted.