#226 MusicBoxKit

Build and test a Music Box kit, and run a demonstration under Arduino control.

The Build

Notes

This is a pretty common kit available from multiple sources, although it appears to have been originally produced by icstation.

The heart of the kit is a custom sound generator board with a potted chip, like this one. This is one of a range of boards - all with potted chips - that I believe are primarily produced as the sound effects generators used in toys.

This kit basically adds supporting circuitry on a PCB to:

drive a piezo speaker
decode 4 switch inputs into the necessary signals required to drive the sound board.

I demonstrate driving the module with an Arduino - very simple matter of pulling the inputs A-B-C-D high/low accordingly, master on/off thrown in for good measure. Of course, if you really wanted to use a sound chip like this with an Arduino, you could just control it directly.

Does this generate good sound effects? No! Twee at best, horribly poor immitation at worst. But if you want to sound like a cheap toy, this may be exactly what you need;-)

Kit Specs

Suite name: 16 Music Box
Kit Model: BOX-16
Operating voltage :4.5-5V
PCB size: 48mm (length) * 42mm (W)
Control modes: manual coding + external coding

16-tone box under your control, arbitrarily issued 16 kinds of interesting analog sound, both an electronic toy can also be used as a doorbell or alarm.

Kit Parts

The kit I received contained all the parts required, including some extra resistors and a random capacitor!

MusicBoxKit_kit_parts

The piezo buzzer supplied with the kit proved to be very poor match for the circuit. I replaced it with another I had available and improved the sound quality significantly - though it is still not great.

Sound Library and Demo Program

The four switches A-B-C-D select the sound to be generated:

ABCD coding	Sound
0000	Machine gun voice
0001	Fire truck voice
0010	Ambulance voice
0011	The police car voice
0100	Crickets sound
0101	alarm
0110	Electronic signal sound
0111	koh
1000	Insect song
1001	whistle
1010	Telegraph sound
1011	Bird song
1100	ChongJi gunfire
1101	Car sirens
1110	Bass instruments sound
1111	Racing sound

Breakout pins for A-B-C-D are provided. With the switches open, these pins can be used to control the board from an external sources. The pins are low by default, and just need to be pulled high.

CK9561 sound effects module

The KD9561/CK9561 effects module is widely available.

It’s a potted chip on a board, primarily intended to be used in toys. Details are hard to come by. the best information I’ve found is this:

CK9561_application_schematic

How Switch Inputs are Multiplexed

Perhaps the most interesting as pect of the module is the way it uses the two CMOS ICs to decode the switch inputs in order to control the sound module.

CD4011 is a quad two-input NAND gate
CD4066 is a quad bi-lateral switch. Each control pin (active-high) switches the path between the two associated IN/OUT pins.

I haven’t traced the entire circuit. But for example, here’s the equivalent circuit for the part that controls the “RF” resistance between connections 8 and 9 on the sound module:

circuit_analysis_part1

Switch A input	Switch B input	4066/1 Out	4066/3 Out	RF Resistance
0	0	0	1	270kΩ
0	1	0	1	270kΩ
1	0	1	1	50kΩ
1	1	1	0	670kΩ

Driving the Module with an Arduino

The MusicBoxKit.ino sketch is a simple demonstration of the module. It runs a demo that cycles through the 16 sounds.

To drive with an Arduino:

5V power is supplied from the 5V pin of the Arduino. The board can draw a peak of near 100mA, but that is within the capabilities of the Uno
a low-side n-channel MOSFET is used to switch the board on and off (controlled by a digital pin)
4 digital pins are used to provide the inputs A-B-C-D
(optional) LEDs are included to indicate the state of the 4 A-B-C-D inputs and the MOSFET gate signal