This instrument is easy to build and fun to play with.
The Arduino (I'm using duemilenova) in this instrument is acting only as a power source and as a simple timer, so if you don't have one you can still build this instrument with other timer sources, like 555 for example.
I took the simple Blink sketch and changed the delay to 100ms.
The timer is connected to the 4022 while each of its output connected to a 10k pot and a switch and from there to the VCO of 4046.
The output wave is square.

The samples:
cicadaboom111.ogg - clean recording. On the 1:28 minute you can hear what happens when the 4046 pin 5 is not connected to the ground.
cicadaboom222.ogg - the sound is going through an effects software, Rakarrack.
cicadaboom333.ogg - the sound is going through an effects software, JACK Rack.

Step 1: Parts and Components

- Arduino or any other timer, for example 555
- 4022 Octal Counter with 8 Decoded Outputs
- 4046 PLL
- 8X 2N2222 NPN Transistor (or any other NPN for switching)
- 8X 10k potentiometer
- 8X push buttons
- 4X 470n capacitors

More stuff:
- Audio socket
- Breadboards
- Jumper wires
- a plastic box

Step 2: The Circuit

few notes:
- Note the block of 2N2222, 10k pot and switch. You should make 8 such blocks for each 4022 output.
- The capacitors (along with the pots) determines the range of frequency for the synth. I chose 4X470n for low frequencies and if I want to play with the general pitch I just remove or add capacitors to the breadboard so anyway you can put switches between the capacitors.

Step 3: Photos

<p>Is there a way to make this into 6 step sequencer?</p>
You could replace the octal counter with a hex counter (3 stage johnson counter), you'd only need 6 buttons, pots and switching transistors too.<br><br>For the people asking about the 555 timer, just look up how to wire a 555 in astable mode. You can add a pot to the 555 to make the tempo adjustable. <br><br>Output from 555 (pin 3) connects to the clock pin on the counter
<p>Hi , do i need to do anything special with the Arduino apart from linking it up? I have one but just not used it yet. Do i need any kind of code? this is an amazing built really looking forward to making it!!!! :D</p>
<p>Great sequencer. I like the 1st and 3rd audio files the most. I plan on making something similar based on this project.</p>
I'm still trying to work out how to wire a 555 instead of the Arduino. I want to build this, and the 555 is a more feasible option for me. I do love the sound on it either way.
I'm also interested in how you'd use a 555 timer circuit for this sequencer! it sounds awesome and i'd like to make one without using my arduino... Would it be hard to change the 555 and arduino clock for a Midi clock signal?
hey, im exited about this! ive been looking at TB-303s, and am in love with my APC, (a 555 instrument) could you give me more directions on how i would build it with a 555 chip? thanks! great job<br>
Hey do you have a higher resolution image of this? I'm planning on building this and I'm a little unclear on where the eight lines attach to the 4046. Are they all on the same pin?<br>Also, what's the clock frequency you're getting from the Arduino?
Actually, this was a high resolution image but when it was uploaded the resolution has been changed.<br>Yes, the eight lines from the switches attached to the same pin (11) of 4046.<br>The clock freq from the Arduino is 100ms but of course you can put a potentiometer as an input to the Arduino in order to change it
I just uploaded a ZIP file with the circuit :))
You, sir, are a gentleman and a scholar.

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More by nivini:SCRUM monkey Cicadaboom - 8 step sequencer and a simple synth Servo Controlled Labyrinth 
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