Arexx CLASSICAL PIANO CP-01 User manual

1
CP-01
MANUAL
CLASSICAL PIANO
www.arexx.com
V20179

2
CLASSICAL PIANO CP-01
Product information:
This piano is an electronic miniature version of the well-known classical piano,
containing 49 keys and 23 preprogrammed melodies. The red keys are control
keys for the volume, tempo, style and for many other functions. The piano is
preprogrammed with 5 di󰀨erent tone-styles and provides a repeat and demo
key. The system allows playing preprogrammed melodies, but also allows
saving and playing your own melodies.
The piano is available as a pre-assembled model but also as a kit for custo-
mers who may be prepared to use soldering equipment. The pre-assembled
piano model is a wonderful business present, a marvellous toy for young and
old, for music-lovers and beginners. This booklet not only contains a step-by-
step instruction manual, but also ample information concerning the world of
music.
Our product line involves several educational electronic and robotic systems,
for youngsters and adults. Have a look at our websites: www.arexx.com.
Specications:
o
Soundrange F ~ F (2 Octaves with a chromatic scale)
15 Volume steps
23 Registered melodies
5 Drum rhythms
4 Percussion sounds
4 Animal sounds
19 Tempo di󰀨erences
Record and play function
Power supply 4.5 Volt (3 pcs AA batteries)
© CLASSICAL PIANO is a trademark of AREXX, The Netherlands en DAGU, China.
© AREXX en DAGU are registered trademarks
© All rights reserved.
Reprinting any of this instruction manual without our permission is prohibited.
The specifications, form, and contents of this product are subject to change without prior notice.
We are not liable for disadvantage or damage caused by improper use or assembly.

3
* When you open the plastic bags of the parts the return right will be disposed
* Read before you start assembly the complete instruction manual
* Be careful with tools and always keep it away from little children!
* Keep this product out of reach of children and do not build this kit when children are in
the neighbourhood, the tools and parts are dangerous for children
* Check the polarity of the batteries
* Keep the batteries dry, when the PIANO gets wet remove the batteries and let the
PIANO dry for some time
* Remove the batteries when you are not using the PIANO for a longer period
Contents
1. Product information 2
2. Partlist 4
3. Necessary tools 5
3.1 Soldering techniques 5
4. Electronic part assembly 6
4.1 Soldering of the parts 6
5. Final assembly 7
6. Function test 10
7. Description of the keyboard functions 11
8. What is a synthesizer 13
9. Circuit diagram 16

4
O PCB 1 pc. O Piano cover 1 pc.
O Piano arm 1 pc.
O Speaker 1 pc.
O ELCO 3 pcs.
O Roundhead
Screw M2 x 5
13 pcs.
O AREXX IC 1 pc.
O Battery holder
1 pc.
O Opamp IC 1 pc.
Push switch
O Hinge
3 pcs.
O Nut M2
10 pcs.
O O-Ring or
Distance holder
O Rubber tube
5 pcs.
O Rivet 3 pcs.
O Condensator
6 pcs.
O Resistor 14 pcs.
O Mounting for
speaker
3 pcs.
O Flathead-
screw
M3 x 8 2 pcs.
O Screw long
M3 4 pcs.
O Nut M3
6 pcs.
O On/O󰀨
Switch
1 pc.
O Wire
Red 1 pc.
Black 1 pc.
O Feet 4 pcs. each
2. PARTLIST
O LED 1 pc.
O IC Socket 2 Pcs.
O White 15 pcs.
O Black 10 pcs.
O Red 14 pcs.
O Blue 10 pcs.
LM386
Sound chip
Tube Feet

5
Long-nose plier
Solder
0,8- bis 1mm
Soldering iron
(15 to 30W)
Diagonal cutter
Soldering iron
stand
3. Necessary tools
CAUTION
• Read this manual carefully in advance to fully understand how to assemble this product.
• Children below 14 may only assemble this product with the help of adults.
• Be careful with the tools. Especially be careful with sharp tools such as nippers or cutter
knife to prevent any injuries or accidents.
• Never assemble the kit when a younger child is around. The child might touch sharp tools or
swallow parts or a vinyl bag.
• Be careful with sharp edges of parts.
* Do not mix old and new or recharchable and non rechargeble batteries.
• Take out the batteries when you do not use the Piano for more than a week
• The specication, shape and size of the product are be subject to change without prior notice.
Screwdriver set
Soldering tools are only necesarry for the soldering required KIT
Necessary Batteries:
AA Batteries, 3 Pieces
(not included)
Troubleshoot soldering mistakes:
1. Preheat the solder area which
must be soldered AND the com-
ponent wire with the tip of the iron.
Do NOT overheat it!
2. Add some solder to the
soldering area and
component wre but NOT
TO MUCH!
3. Remove the solder and let
the hot liquid solder ow.
4. Take away the soldering iron
and DO NOT MOVE the
component or PCB!
5. Cut away the long component
wire just above the soldering spot.
The END RESULT is a nice and
shinny soldering spot which is
attached to the PCB copper and
component wire.
3.1 Soldering techniques:
Hold the iron like a pencil
Only add a little solder each time
Correct position for professional soldering
PERFECT SOLDERING
The soldering surface
looks nice and shinny
Not enough solder
Solder did not ow
Solder bridge
Two seperate solder spots are
connected to each other
Cold PCB
Solder is attached to
comonent wire but not to
the PCB copper
Only use leadfree ROSIN CORE solder!
Never use any liquid- or paste ux!
PASTE

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First please check if all parts are complete with help of the partlist.
The markings on the PCB show exactly on which position you should solder the parts.
If you need more information please check the drawing of the PCB.
We always start to solder the lowest parts and end normally this are the resistors. We
advise to cut the component wires directly after soldering so they will be out of the way
when you start soldering other parts.
Before you start to solder we advise to check if the IC’s t correctly, when necessary
align the IC pins with a at nose plier or bend them over all together when all pins rest
on the table.
THE POSITION AND POLARITY OF THE IC’S IS MOST IMPORTANT!
• Please study the soldering instructions on the previous page rst
• Check all invidual components with the help of the parts checklist.
• Start soldering the resistors and capacitors (passive components)
and solder the diode, transistors and IC‘s (active components) after that.
• Insert the parts on the PCB top (printed side) and solder the component wire
on the bottom to the PCB (Copper side).
4. Electronic assembly
4.1. Soldering of the parts
PCB
marking
Polarity &
Marking position
Resistor
No polarity.
In professional soldering it is common
use, to have all accurrancy (gold)
rings at the right side.
Position the IC‘s in the
good direction (see
markings!).
FIRST SOLDER
THE IC FEET!
IC
The colored rings show
the resistor value!
□ U1 sound chip
□ U2 LM386
Be sure marking is 100%
OK, this marking can also be
found on the PCB!
Remarks
IC Marking
Partnumber
Switch
No polarity.
□ R1, R2, R3, R4,
R5, R6, R7, R8
330Ω or, or, bl , gold
□ R9, R12 470Ω vio, yel, bl, gold
□ R10,R13 1KΩ brn, bl, rd, gold
□ R14 10Ω brn, bl, bl, gold
□ R11 3,3KΩ or, or, rd gold

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Important! insert the LED in the correct
way, see length of the wires.
Polarity of the elco is important otherwise
you can damage the circuit or it will not
have a correct function.
ELCO (ELektrolyt condensator)
Capacitor LED (Red)
No polarity.
□ D1
Important: notice the
correct Polarity A and K.
The at side on the led marks
the cathode.
The long leg is the anode.
Speaker mounting
M2×5mm
Roundhead
screws
Speaker
Bottom side
PCB
5. Endmontage des Pianos (bei AW-860K is alles bereits vorgelötet !)
5. Final assembly of the Piano
For the wiring of the speaker you need a red and black
wire. When necessary you have to prepare them in the
following way.
1) Remove about 5mm of the
plastic wire insullation
2) Twist the copper wires
3) Presolder the copper
wire. If this step is done,
it will be more easy to
solder the wire in a later
step.
5.1. Assemble the speaker to the PCB
Polarity &
Marking
position
PCB
marking
Partnumber
Remarks
Wire preparation
Polarity &
Marking
Part
number
Push switch
White 15 Pcs.
PCB
marking
No polarity
□ 1st row (Fa - Fà)
Solder the 4 switch pins
Push switch
Blue 10 Pcs.
No polarity
□ 3th row (tone & function)
Push switch
Black 10 Pcs.
No polarity
□ 2nd row (fa# - re#)
Push switch
Red 14 Pcs.
No polarity
□ 4th row (rithme)
Notice
□ C3 220μF/--V
□ C6 220μF/--V
□ C9 220μF/--V
--V Must be higher than 6V
□ C1,C4,C5 100nF
C7,C8 (104)
□ C10 33nF (334)
The long leg is marking the
The white band on this part is marking
the lead.

SEE PAGE 8

8
5.3. Assemble the tree hinges halves to the
PCB top
TOP side
PCB
M3×4 Roundhead screws
Metal hinge assembly.
Please notice the
direction of the hinges!
Please check if your assembled PCB
looks the same way as the drawing.
It is important to check the polarity and
direction of the parts.
• Drawing of the assembled PCB TOP
5.2. Solder the speaker wire in red spot as
shown in the drawing below
Speaker
Vinyl cable
Bottom side
PCB
M3 Nut
Flathead screws
Solder the battery wires to the PCB
(red spot) as shown in the drawing.
5.4. Installing the batteryholder to the
PCB.
The polarity and is not important

• Solder the red wire to the + spot on the PCB.
• Solder the black wire to the - spot on the PCB.
** Notice new + and - Position!!!
option M3
distanceholder!
BLUE
RED
BLACK
WHITE
Here you
also may
use the 2
washers
**! **!
** Notice new + and - Position!!
X
+SP
-SP
**!

9
5.6. Installing the hinges to the piano
cover. NOTICE the correct direction!
Top side
(side with the parts).
M3 Nut
M3 long
Roundhead screws
5.5. Install the piano feet to the PCB
M3×4 Roundhead screws
Metal hinges
Piano cover
NOTICE the
correct direction!
Feet tube
5.7. Assembly of the cover and piano arm
Assemble the piano cover to the PCB, be sure that the metal hinges are
connected exactly as shown on the pictures.
Piano cover
Piano arm
Rivet
Rubber tube PCB
Metal hinge
a. Cut 3 pcs of the plastic tube with a length of about 5 mm,
you can use the simple measurement line:
c. Connect the piano cover to the PCB
Piano arm
Metal hinge
Rubber tube
b. Connect the piano arm to the PCB hinge
Piano cover
Rivet
PCB
Metall hinge
Rubber tube
5mm
Simple measurement line:
Rivet
The assembled piano
Feet
Install 4 Pcs.

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a. Insert the batteries into the battery holder. PLEASE NOTICE the correct polarity
of the batteries!
b. Lift the piano cover and place the piano arm
NOTICE: you can stop all playing actions directly with the STOP button!
c. Switch on the ON/OFF switch (you will hear a starting tune)
CAUTION... if there is any smoke or a component getting very hot, switch o
the piano immediately and check all part directions!
d. Push any of the white or black push buttons, you must hear a sound. If not,
check batteries rst and then all part assembly.
e. Push the black DEMO button, then you should hear a melody. Push for more.
f. During a DEMO melody you can check the VOLUME + and VOLUME - buttons to
see if the soundlevel changes
g. Push the START button. When the tune stops, randomly push the white buttons.
Now you hear the tune like you play it yourself.
h. Push the RHYTHM button, then you will hear the rhythm section. You can change
the speed with the TEMPO buttons
i. When another rhythm button is pushed, the rhythm will change
j. When playing a rhythm, you can change the TEMPO with the TEMPO - and +
buttons
k. Play a DEMO tune and change the instruments by pushing the INSTRUMENT
button. You should hear di󰀨erent instruments now
l. Push the RECORD button and play your own melody
m. Push the REPLAY button to listen back your own melody
More about the keyboard functions, see chapter 7
How does a synthesyzer work,see chapter 8
6. FUNCTION TEST

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7. Description of keyboard functions
The synthesizer in the Classical Piano has been preprogrammed. Press the
instrument key once or repeat the key to change the available instrument
styles. Pressing the key will activate the processor to load the synthesizer
control parameters from the chips memory into the synthesizer processor.
This allows you to switch from playing a piano to playing a trumpet organ.
The Classical Piano synthesizer provides two independant tone generators,
allowing you to hear two di󰀨erent tones at pressing two keys simultaneously.
This function however will not be available for all instuments. Pressing more
than two keys will result in playing the melodies for two initially activated
keystrokes. Professional synthesizer systems of course provide more than two
independant tone generators.
DESCRIPTION OF THE FUNCTION KEYS
Start
Select and start the rst of the preprogrammed melodies
Rhythm box
5 di󰀨erent rhythm styles
Tempo+
9 faster tempo levels for percussion styles or preprogrammed melodies
Tempo-
9 slower tempo levels for percussion styles or preprogrammed melodies
Instrument
Select your preprogrammed instrument from piano to trumpet

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Demo
Toggle between several preprogrammed melodies.
Select a preprogrammed melody by pushing the key again. While playing a
melody, you may alter the instrument by pressing the tone key and alter the
tempo by pressing the tempo keys. Starting another melody will start the tune
in a standard tempo.
Percusion
Hitting this key will select a standard percussion style or an animal sound.
Record
Toggling this key will activate / deactivate the recording system. Playing your
own melodies will be recorded and may subsequently be played.
Play
Your previously recorded melodies will be played as long as the melody re-
corder/player is active. At the end of a tune you may record another melody,
which will be concatenated to the previously recorded tune. Press the play key
to play all recorded melodies.
Volume+
7 higher level playing volumes
Volume-
8 lower level playing volumes
Stop
All running activities will be stopped immediately

13
The word “synthesize“ may be translated to “put things together”. Obviously a
synthesizer provides a system to produce any kind of sound, e.g. the sound of
a musical instrument or even the sound of a thunderstorm.
A synthesizer transforms electrical energy into all kinds of tune signals. These
tunes may be transformed by several special e󰀨ects. A single chip will provide
all these functions. In the end the signals may leave the synthesizer chip and
enter the loudspeaker to be heard by the human ear.
A synthesizer provides a number of signal generators. Several tone genera-
tors will be used to produce pure frequencies at a predened pitch, which will
generate a clean acoustic wave at a loudspeaker. Synthesizers also provide a
noise generator, which is used for producing hissing, whistling and percussion
sounds. Of course the system will need a mixer to add several signals and a
number of lters to eliminate or to enforce signal spectrums. Some synthesi-
zers will contain a slow oscillator function, generating a slowly increasing and
decreasing signal, used to modulate the volume or pitch of a tone generator.
Modulating the frequency of a tone generator by a slow oscillator signal will
result in a slowly increasing and decreasing frequency, which we will interprete
as a siren signal. At a faster speed and at a lower level the tone generator will
produce a vibrating tone and the e󰀨ect is called “vibrato”. These functions will
all be provided in a single chip!
In a synthesizer all functions may be altered or programmed, e.g. the pitch,
the sustain period, pitch or volume alterations and lter parameters.
Using only four parameters you may imitate almost any instrument: Attack,
Decay, Sustain and Release.
8. What is a synthesizer

14
If a guitar player for instance strums one single chord, we will hear a “ploink“-
sound, which will end abruptly as soon as he lays his nger on the chord.
The sound wave starts suddenly with a “pl” in “ploink” (Attack), quickly de-
creasing (Decay), followed by a constant phase (“oin” = Sustain) and suddenly
stopped by a nger at the chord (“k“ = Release).
The synthesizer will be able to imitate any acoustic source by generating a
sound wave and varying the duration of these four parameters for this sound
wave.
Varying the 4 parameters in a noise generator wave results in a good imitation
of percussion instruments and adjusting the lter parameters for a noise gen-
erator wave allows us to imitate almost any whistling sound.
Overview of the standard synthesizer modules and parameters:
Oscillator:
A wave generator providing a programmable frequency and wave amplitude
Envelope:
The wave amplitude as a function of time
Filter:
A module for emphasizing, weakening, or removing a frequency spectrum
Lowfrequency oscillator:
A slowly varying and adjustable signal source, used to control a pitch or volume
of an oscillator.
Attack:
A „stroke“, suddenly raising the sound wave up to a maximum level.
Decay:
Decreasing phase (from a maximum to a constant level).
Sustain:
A constant level phase
Release:
Extinction phase of a sound wave

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Mixer:
Module, used for mixing several sound waves.
Amplier:
Module, used for amplifying the weak synthesizer signals up to a loudspeaker
level.
Early synthesizer versions were volumineous boxes and cabinets, containing
a great number of analog modules and a lot of connecting cabling. Modern
integrated circuits and digital signal processing in software tools allowed mini-
mizing size and cabling of the synthesizer equipment.
MIDI
In order to interconnect di󰀨erent synthesizer modules or synthesizers we use
a standard synthesizer-language, called MIDI (Musical Instrument Digital
Interface).
MIDI-words may be understood as special codes. One of these codes is used
to control the pitch and another code controls the duration of a tone. A com-
puter may easily store code sequences in a MIDI-le and send the MIDI-le to
a synthesizer. The synthesizer equipment however must contain a so-called
sequencer to process MIDI-codes and to activate all synthesizer modules at
exactly the right moment.
Of course a sequencer may also be a computer program. Some computer
programs may even imitate or emulate a synthesizer. Complex sound modules
in a standard PC may already be equipped with a midi-interface (sequencer)
and a (more or less complex) synthesizer module.

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1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
D D
C C B B
A A
AREXX Engineering Nervistraat 16 8013 RS Zwolle
the Netherlands www.arexx.com
Piano Board Title:
Drawn by: Checked by:
Document number:
RevisionSheet ofDate:Size:
A3 BSC - 1.01 1
ARX_003_01_SCH
01-08-2017
PCB
_PCB1
ARX_003_01_010_PCB
PCB
S1 .fa
S2 .fa#
S3 .sol
S4 .sol#
S5 .la
S6 .la#
S7 .ti
S8 do
S9 do#
S10 re
S11 re#
S12 mi
S13 fa
S14 fa#
S15 sol
S16 sol#
S17 la
S18 la#
S19 ti
S20 do.
S21 do#.
S22 re.
S23 re#.
S24 mi.
S25 fa.
PA0 PA1 PA2 PA3 PB1 PB2 PB3PB0
R1
330R
R2
330R
R3
330R
R4
330R
R5
330R
R6
330R
R7
330R
R8
330R
Sound Chip
PB3
1
PD0
2
PD1
3
PD2
4
PD3
5
VDD2
6
VREG
7
VPP
8
DAC
9
PP1
10
PP2
11
-
12
VDD4
13
VDD3
14 GND 15
-16
PC3 17 PC2 18 PC1 19 PC0 20
VDD1 21
PA0 22
MODE/PA1 23
SCL/PA2 24
SDA/PA3 25
PB0 26 PB1 27 PB2 28
U1
S34
Volume up
S26
Volume down
PC0 PC1 PC2 PC3 PD0 PD3
GND
GND-R
R9
470R
S30
Tempo Up
S31
Tempo Down
S28
Record
S29
Playback
S32
OK/ON
S33
Stop
S27
Cymbal/Frog
PA0 PA1 PA2 PA3 PB0 PB1 PB2PB3 PC0 PC1 PC2 PC3
PD0 PD1 PD2 PD3
VDD VDD VDD
VDD
VDD
GND
GND
DAC PP1 PP2
S35
Demo
Buttons
Sound Chip
Power Entry Amplifier
C1 100n
R12
470R
C5 100n
R11
10k
R13
1k
GND
GND
DAC
AMP-IN
LM386
GAIN1
-INPUT 2
+INPUT 3
GND 4
VOUT
5VS 6BYPASS 7GAIN 8
U2
GND
AMP-OUT
C8 100n
C7 100n
GNDGND VDD
R14
1k
C10 33n
GND
+
C6 220u
Pad3 Pad4
GND
Pad1 Pad2
GND
D1 Red
R10
1k
GND
+
C3 220u
+
C9 220u
GND
C4 100n
GND GND
S36
VDD
S38
Pedal Hi-Hat/Duck
S39
Snare Drum/Dog
S40
Bass Drum/Bird
S37
Percussion Switch
S41 Piano
S42 Guitar
S43 Organ
S44 Violin
S45 Trumpet
S46 Slow Rock
S47 Rock
S48 Twist
S49 Cha Cha
S50 Samba
PD1 PD2