Idea for Octaswitch workalike

[jubal81]

I've been thinking a lot about how to make one of these for a few days since I'm piling up the pedals and want to be able to use them better together.

For those of you that aren't familiar with the Carl Martin Octaswitch, it works almost like a 'programmable' loop selector. You can assign different loops to eight footswitches.

I think I have a rough idea together for how to do this.
If you look at this article by RG:
http://www.geofex.com/Article_Folders/multivol/multivol.htm

The part at the bottom shows how to get a steady signal from one and only one momentary switch at a time. It seems to me that if you were to rout each of those steady signals to one of eight DIP switches, you could send that signal on to a non-latching relay at each loop. Just set the dip switches to which loop you want each switch to put into the signal and you have a 'programmable' set of momentary stomps with true-bypass loops.

Seems like you could do it with a couple really cheap chips plus all the switches, jacks, DIPs and relays - and a lot of time.

Is this right or am I missing something?

Also, I've got a plan for how to do away with all the dip switches and replace them all with a single rotary encoder. The problems I have with that Idea is that right now it would require 29 chips and wouldn't 'remember' the settings after the power is turned off. 

[shawnee]

I'm interested, however I can't be much help.

[insomniac2295]

I'm interested, however I can't be much help.

Same for me. I've always wanted an Octaswitch, or even to build one (I love DIP switches). From what I've read though, actually building one could be pretty difficult, or like the OP said, time consuming.

[jubal81]

OK. It's officially time I learn how to program PIC micro controllers.
Bought the development tools online today.

Anyone have good links for learning Assembly language?

[JakeFuzz]

If you read back or do a search I've outlined how exactly to make an octoswitch with a microcontroller and relays. The circuitry is not really as complicated as it is repetitive.

Also skip the pic and go with an Arduino. C is a much easier language to learn and for this application you don't really need to shave down compute cycles. The Atmel microcontroller on the Arduino is super easy to move to a separate board, I did it for three biomedical trade show devices a few weeks ago. I did it all on vero board too. That and the Arduino is pretty much perfect for prototyping stuff, you can plug and unplug as many times as you like to get things working like they should.

The code will be very simple, just de-bouncing switch inputs and setting the right digital outputs high. If you need some help with the code or the circuit I can always take a look at things. I too would like to get this to work but don't really have the time or desire for something like this for myself.


Edit: Oh you already bought a PIC? They have a C compiler for PICs. I think it is called MicroC or something like that. I am not too familiar with the entire instruction set. Are you planning on using the internal clock? Most people use an external crystal.

[jubal81]

That's for the heads up, Jake.
I spent a couple days looking into the different chips and decided on pics since you can get simple ones for less than $1 each vs. about $4 for an AVR or a PicAxe. Not to mention you can get them in smaller sizes.

I'd like to eventually find more uses for them than just switching relays, so going with the PIC seemed to make more sense. Also, I looked at different coding tutorials and while the arduino is easier, I figured if I'm going to learn to program I might as well man up and learn the hard way.

The kit I bought was $50, so I imagine down the road I'll end up buying an Arduino, too, since these things each cost less than my typical Mouser order.

I have no idea if C is that much easier than Assembly. I went through some Assembly tutorials and was able to catch on a bit.

If you have any more advice I'd love to hear it.

Edit: I've only been looking into this stuff for a few days, so I don't know enough about the benefits of an external crystal. My guess is that it's somehow more consistent or maybe more durable?

[JakeFuzz]

C is definitely easier than assembly language. Even the computer science guys I work with really hate ASM. With C you have much more control over conditional statements and math operations. I think the PIC compiler actually allows you to program in ASM and C at the same time which would be nice. PICs are definitely powerful though and easier to integrate into your own designs.

The best place to start would be the chip manual by Microchip. They include a list of supported functions which should be enough for programs like this.

For the octaswitch I would start looking at processing analog inputs and outputting digital signals to specific pins. Then I would look at something called a "case" statement which is like a menu function that allows you to choose lots of different things based on a single variable evaluation. Also you will probably run everything inside an infinite while(1) loop just to keep the program going. "if" statements and boolean operators are always essential for evaluating your variables and performing actions based on their values.

It's going to be fun though. I really enjoy programming stuff that actually physically does something. Much more satisfying than writing like FEA code.

[jkokura]

Hey Paul,

I'm wondering if you can do a post on some of the basic uses for Arduino, and how one would get into it. I've been wanting to learn more about how to incorporate these digital devices, both Arduino and PIC, into some pedal projects in the future, and it seems like you have a good idea already. It'd be very welcome to see a sort of "beginners info package" available for us, specifically how it applies to pedal building, because I know that pedal building is not the sort of use Arduino or PIC is generally used for.

jacob

[JakeFuzz]

Sure Jacob Ill start a new thread in this section.

[Feral Feline]

Came across this old thread via an Internet search;
post a link from this thread to the "new thread" JakeFuzz mentions in the post above?

IS it the link below?
http://www.madbeanpedals.com/forum/index.php?topic=3271.0