Digital Pedalboard

[New Frontier]

Hello All..

I'm studying Electronics Engeneering and my teacher asked us to star thinking about our final project...

I play the guitar and like so much this stuff about effects and pedal, and thought I could to something about it, but, she told that the project HAVE TO use a microcontroller, or something like that...

:?:  Has anyone on this forum projected or experienced a project like this :?:

I know I I'll have to project it, but I'd like to have references to start the whole thing.

[travissk]

What type of microcontroller will you be using? You're going to have a hard (or impossible) time doing DSP if you're limited to an Atmel or a PIC, even though some things might be possible like bitcrushing. I'm not sure how long you have for your project, but a simple PIC a/d->bitcrusher might be a little to simplistic, not to mention the fact that, well, bitcrushing can do strange things to your sound, and those who are used to hearing "normal" guitar sounds might think your project is broken. It takes a true connoisseur to appreciate some effects

If you can interface with a DSP chip, however, it might open up some possibilities. Peter is definitely the guy to answer this, but from what I can remember the Alesis 1K chips are pretty cheap. Search for a thread called "DIYDSP" (or "DIY DSP" ?), and he recommends some chips that go for a couple bucks a piece and give you 1024 instructions if I remember right. You can't use any sort of branching instructions, so I'm not sure you could use it on its own for the project (since they probably want you to have some sort of state logic), but you could integrate an algorithm-switching microcontroller... with that level of complexity, however, you're probably getting in over your head in case something goes wrong.

Also, do you guys have access to anything else beyond microcontrollers? We had to make a synthesizer and a couple games using Verilog on an FPGA board, so it is certainly possible to program some effects in there, even a simple delay, feedback loop, sampler, or whatnot.

[bobbletrox]

Make a USB Nintendo Controller for PC!  

I've been told it's quite easy to do with a microcontroller and some simple programming.

[Peter Snowberg]

Instead of looking for processing the sound digitally, I would concentrate on using a microcontroller for routing signals. I don't know how complex your project has to be, but if the complexity isn't extreme, consider making a digitally controlled patch bay using an Atmel AVR or Microchip PIC and a few relays.

My suggestion: Make a board with six or eight relays, a footswitch and status LED for each one, a "learn" button, a "manual" button, an "Up" button, a "Down" button, a seven segment LED to display the preset number, and an LED above the "manual" button to show status.

With the "manual" function on, each switch (#1-6 or 8 ) controls a relay directly, allowing you to control a set of pedals with true-bypass switching even if the pedals don't have it. With "manual" off, each button selects a preset configuration which is saved in the microcontrollers EEPROM.

The "up" and "down" buttons would select the preset number you wanted to use (which is then displayed on the 7 segment LED). If "manual" was on, pushing "up" or "down" would not affect the relays.

The "learn" button would copy the current status of the #1-6 switches to EEPROM.

You would use all momentary SPST footswitches which reduces the cost.

That will give you a nice patch bay.

I would avoid trying to process the signal digitally for your project if you're just starting off with microcontrollers. If your project need to be more complex, I can come up with lots of options for you.

take care,
-Peter

[Arno van der Heijden]

Start reading here:

http://www.geofex.com/Article_Folders/ASMOP/ASMOP.htm

[New Frontier]

Hello All.. Tks for your attention.. It's good to be again on a serious forum.. The ones I've visited were preety boring !!

Well, I have 3 years to develop my project.. I started early, 'cause I want to give it a lot of thought, because I don't want to regret after the choice (like on my technician degree project).. So I'm looking for the possibilities, and all the inputs are welcome. The project can't be very simple but doesn't need to be an ET project..

I had some experience with PIC controllers and Z80 processors.. Actually, I'm not THAT bad with programming, so I think I can go for it..

I want to make something usefull and kind of reliable, but I don't want to reinvent the wheel !!!

Tks again

[niftydog]

I have 3 years to develop my project

christ on a bike!  How long is the course?!  Full time or part time?

I've got till the end of this year to do my project... and I'm not sure what I want to do yet!  Technically, we're given one semester of class time to do it in... that's about 4.5 months, 3 hours a week, plus our own time.

If you've got some experience in PICs in your first year of an engineering course, you'll have plenty of time to hone those programming skills!

[New Frontier]

Hello All

My course ia a FIVE year one !!!! It's a part time course..

Actually, we start to think about the prject in the last 3 semesters of the Engineering course, but, because my job draws almost all my free time, I started to PLAN the project earlier.
And based on my experience in the Technician's couse project, it HAVE TO be well planned, or else it will be a serious headache !!

Tks

[smoguzbenjamin]

Whatever you do, good luck!