the sudomini uses a NE555 timer chip to create a simple oscillation
My plan was to make the sudomini from the dirty electronics manual, however I was unsure about the circuitry shown in the schematics so I decided to first make a prototype on a breadboard.
Below are the steps I took
First place the chip across the middle divider and
connect power to the bus
take positve bus to ne555′s pin 8 (vcc)
from chip 1(gnd) chain at the end to ground
put a ceramic disk capacitor 0.1 uF connecting pins 1-2
100uf electrolytic capacitor between 3 and another channel not being used(later connected to positive side of speaker)
put a resistor between pins 7+8, the schematics said to use a 10k resistor (I used a 100k pot to give more flexibility being able to control the range of pitch)
then connect the channel the electronic capacitor to the positive side channel of the speaker, in this case piezo buzzer
then connect the negative side of the speaker to pin 1 after 0.1 uF capacitor to ground it.
between positive and ne555 pin 8 , connect a cable running to pin 4. leaving a space before the chip.
take a cable from pin 6 to pin 2 after the disk capacitor
put two jumper camels at the the top of pins 6+ 7, this is what you complete the circuit with holding one in each hand so your body is the resistor.
Once I had the circuit working and was sure about the wiring I began building my sudomini.
The circuit is exactly the same as the prototype except I used a 8 ohms miniature speaker and as the circuit was going to be mounted underneath the speaker the circuit had to be as small as possible.
I had to gently file between the strips of the chip so the circuit didn’t short out, the same as placing it over the center divide on the breadboard.
the electrolytic was the attached straight to the positive side of the speaker
pins 6 from the chip went to the isolated bolt and pin 7 to the outside of the tin, so you have to hold these to places to complete the circuit. battery is mounted on the outside for these photos so you can see inside more clearly.
with 1ook pot to change rang of pitch mounted on the side
