Guitar Hero Controller Synth

This is a modified Playstation 2 Guitar Hero controller. Just about everything is left the same with only slight modifications to the actual controller. The circuit that drives the oscillator is based on the LM386 amplifier chip. Here's the schematic. You can download the full image here.

In this image, I actually inverted the resistors. The 50k ohm should be at the top and the 10k ohm should be at the bottom. That way, the lower tone is connected to the higher up keys and the higher tone is connected to the bottom keys, the way a real guitar is. Here is another picture which corrects this.

Because of this layout, you still get a low tone if you strum without pressing a key because the potentiometer is also a resistor. When one key is pressed at a time, you will get a different tone but if you press two or more at a time, you will get a high tone. This is because the resistors will be connected in parallel. Here are a few photos of the key board along with the resistor board.

The strum bar was a little tricky. I wanted to use an entirely different board because I was worried that the components on the board would cause some kind of short circuit. I was unable to find a board big enough to fit across the strum bar so I ended up using the original board. I had to cut several traces to ensure the current from the square wave circuit wouldn't run anywhere else.

The switches are connected to the output jack. I also accidentally inverted the wiring here as well. I connected the Ground to the switches and the switches to ground rather than the signal to the output. This is okay if you use it on a small amp but if you using a real guitar amp, the Ground on the amp will replace the ground on the circuit, which would give a constant signal, and bypass the switches for the strum bar.

If you connect the output signal to the switches (like I was supposed to) you effectively disconnect the signal from the amp until the switches are pressed using the strum bar.

I hope this helps you out if you decide to make this. If you need any help or clarifications email me at adimwit@hotmail.com. Thanks.

Guitar Hero Controller Synth by Justin Bread is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

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Square Wave Oscillator

This is a square wave oscillator (digital, like 8-bit music). It's based around the LM386 amplifier I.C., which is what the mini guitar amplifier was based on. It has a simple power switch connected to the battery, a potentiometer for adjusting the tone, and a normally closed momentary switch. The momentary switch is connected to the signal output. It's normally closed so when you press it, the signal is cut off but when you release it, the signal passes through again to your amplifier. This can create some cool sounds.

I have the schematic embedded below. Feel free to download it here. There is detailed instructable I wrote here on how exactly to build the circuit.

This is a diagram showing the components wired to the I.C. The red x's indicate places where the wires don't connect and the black dots indicate connections. Feel free to download the image here.

This second video contains another square wave oscillator but with keys to jump to different tones and a potentiometer to adjust the overall tone. The keys are actually normally closed momentary switches. A resistor is connected to each switch so when it is pressed, it generates a tone. It's hard to explain here so I'll try to explain it later or in a video.

Square Wave Oscillator by Justin Bread is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

Square Wave with Keys by Justin Bread is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

Both images embedded on this post are Attribution-NonCommercial Creative Commons licensed.