Simple sequencer

Introduction
Feeling all inspired-like from the gig last night, i made a cute little sequencer this morning. I like the fact that it is so very simple to make and so cheap, yet the whole thing can be extended significantly further. It uses digital logic with analog components and can be powered from 3V to 12V.


Theory
Yeah, the whole thing is very basic, and is really made up of three parts controlled by a single pot.

The 40106 provides an oscillator for control and an oscillator for sound output. The output of two of the inverters are fed back into the input of each stage, creating flip-flop type oscillators.

The 4040 creates multiple pulse streams of the control oscillator at binary divisions of its fundamental frequency. The Q1 pin outputs a pulse that is half the frequency of the input clock. Each consecutive Q pin outputs a frequency that is half that of the one before it. So, if Clock = 1, then:

Q1 = 1 / 2
Q2 = 1 / 4
Q3 = 1 / 8
Q4 = 1 / 16

and so on and on. There are a total of twelve output pins.


The 4051 provides a switching mechanism through which various points along a resistance ladder (the 22kΩ resistors) are selected to set the frequency of the oscillator for sound output. Three address pins (A, B and C) control which of the eight address connections are connected to the common pin.

The pot changes the fundamental frequency of the control oscillator. At higher frequencies, interesting effects seem to occur between the three ICs.

Audio Example
Simple Sequencer Example (MP3, 520kb)

Beware: the audio compression compromises the nice sound of wave! For true results, please construct one in physical form.

In the example, different sequences are achieved by connecting the address pins A,B and C of the 4051 to various outputs of the 4040. To be specific, four configurations are used as follows. It should be noted that the configuration in section 1 (A,B,C to Q1,Q2,Q3) has been represented by the logic diagrams and tables and the schematic and breadboard.

Section   Address Pin A       Pin B       Pin C
1         Q1                  Q2          Q3
2         Q6                  Q7          Q5
3         Q5                  Q2          Q6
4         Q12                 Q11         Q5

Here you can see the waveform of the oscillator.


Ingredients
1 x 4051 8 to 1 mux - demux
1 x 4040 12 stage binary counter
1 x 40106 hex inverter
8 x 22kΩ resistors
1 x 1MΩ potentiometer
1 x 0.1uF capacitor
1 x 33uF capacitor

So the total cost might be about $6.


Schematic and Breadboard




Logic

timing:

CK -_-_-_-_-_-_-_-_

Q1 --__--__--__--__ -> A (LSB)

Q2 ----____----____ -> B

Q3 --------________ -> C (MSB)

T: 1 2 3 4 5 6 7 8


truth:

T   Q3 Q2 Q1   CD4051 Address
1   1  1  1          7
2   1  1  0          6
3   1  0  1          5
4   1  0  0          4
5   0  1  1          3
6   0  1  0          2
7   0  0  1          1
8   0  0  0          0