Suggestions for "square one" projects

[David]

Instead of kibitzing on others' posts, allow me to make an honest-to-goodness contribution...

We should get this effort moving in a concrete direction.  Let's establish some baselines.  One code development baseline is always the "square one" or "Hello, World" project.  I think we have to have something like that here.

Project 0 should probably be lighting up an LED (hey, you gotta start SOMEWHERE).
Project 0A might be a PIC version of "Howie's Effects Switcher" or Andrew's "Wicked Switch".  I vote for the latter because I know the original works.

[aron]

Good points. GREAT!

[moosapotamus]

I think that's a great idea, too.
But, with all the discussions about alternative chipsets, languages, platforms, etc... my head is spinning. 
How do you choose?

~ Charlie

[Peter Snowberg]

I think for working in mass, it's a good idea to jump for a vendor supplied eval board. I know a couple of people here are focusing on the Atmel STK500 which is a great platform for getting up and running.

http://www.atmel.com/dyn/products/tools_card.asp?tool_id=2735

They're available for $79 at Digikey: http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=89617&Row=520371&Site=US

PICs do a great job too, as do a few dozen other uC families, but the Atmel AVR parts are my current favorite for general purpose needs.

You can get or build programmers for less, but don't go that route unless you have lots and lots of free time. I feel that solid programming tools are just something that is needed.


Starting simple is an excellent point, David. I totally agree.


The STK500 is actually a combination of a couple of things. It contains a serial based programmer, lots of sockets for different chips, and headers to make prototyping VERY easy. It also has a set of eight push-buttons and eight LEDs on board as easily accessible test peripherals. It's perfect for getting blinky LED code up and then expanding it to play with the other 7 LEDs.

The AVRs all use the same code so choosing the chip is just a matter of looking at how much memory and what peripherals are required for the job at hand.

I prototype around the ATmega128 and then pair down as required. The ATmega128 gives a load of breathing room. 

Here is the link to WINAVR which is a free development environment for AVRs that contains both GNU C and C++.
http://winavr.sourceforge.net/


There may be lots of languages, but it all comes down to logic which you can transfer to any chip with the resources you need. 

[The Tone God]

:::Grumble grumble::: Fine! Thats it!!! I'll write a few lessons/articles and see how it goes. Give me some time.

Andrew

P.S. :::mutter:::Screw you guys.:::mutter:::

[Peter Snowberg]

Wicked micros for wicked switches? Wicked patch-bay? Wicked routing?

This is gonna be cool!

P.S. Thank you Andrew! I was hoping that you might draw up something seeing as how cool your other articles are.

[aron]

Now once we get this going, what can we really do with this stuff?

What type of enclosure will this fit in?
How is it powered?
What can we really do? Make our own programmable pedalboard? Digitally control analog boxes with presets? Code our own overdrive???

Thanks,

Aron

[Peter Snowberg]

Now once we get this going, what can we really do with this stuff?

How about a set of stompswitches that each trigger a preset pattern of eight bypass circuits sitting around analog effects to avoid "tap dancing" between the verses and chorus?

...or a digital LFO that produces a bunch of variable modulation waveforms with perfectly controllable characteristics?

...or how about a digital LFO that drives the clocks of a pair of BBDs directly, one for modulated delay and the other to get through zero flanging?

...or how about preset values being fed to analog effects via vactrols or ePots to act like regular potentiometers?

...or how about PWM modulated filters? The MXR envelope filter works that way.

...or a guitar tuner?

...or a lighting controller for stage effects?

...or to add MIDI control to an analog DIY effect?

...or generating MIDI messages to control other gear like rack processors?

Now that's just a couple examples for digital control. When it comes to DSP, you can do things that you simply can't in analog because of the noise floor of the universe. Huge filters are where DSP shines the most. Reverbs are the next solid application. Most other effects (besides distortion) follow.

What type of enclosure will this fit in?

The STK500 is for prototyping. All final circuits would be MUCH smaller. FreeElectron just posted a picture of a phaser he built which is clocked with an AVR and you can see it takes a pretty small footprint. Digital control can fit in some pretty small spaces.

Phaser pic in this thread:
http://www.elixant.com/~stompbox/smfforum/index.php?topic=42365.0

How is it powered?

Most digital stuff runs at either 5 or 3.3 volts. You can easily get this with a high efficiency linear regulator from the analog supplies we all use. Battery use is available too. These chips run battery operated remote controls all over the place.

What can we really do? Make our own programmable pedalboard? Digitally control analog boxes with presets? Code our own overdrive???
Between digital control, analog circuits, and DSP, the sky is the limit.

Programmable pedalboard? Yes. Analog boxes with presets? Yes. Code your own overdrive? Yes (but you may still prefer the sound of a pair of diodes in a feedback loop with a cap in parallel ).


I think it's important to differentiate between the microcontrollers at one end, and the signal processors at the other. There is a wide range of capabilities available and a wide range of chips to plug into those possibilities. We can take advantage of both of these two technologies.

[The Tone God]

What type of enclosure will this fit in?
How is it powered?
What can we really do? Make our own programmable pedalboard? Digitally control analog boxes with presets? Code our own overdrive???

I think I'll use a format similar to the Beginner's Project. I think the first thing I'll cover is a basic intro to uC and what tools will be needed. I'll continue from there trying to systematiclly cover everything related to the use of uCs for effect DIYers including those issues and others which you haven't thought of yet.

It should be made clear the difference between microcontrollers and DSP and what you can do with each. I'll leave the DSP stuff to Peter since it seems hes got something in the works plus he has the experience or atleast more then I. I will chip in to handle the uC topics.

Andrew

[bioroids]

This is very interesting.

I wonder if there is some kind of simulation soft to check if the code works without building an actual device.

I think everyone agrees in starting with uC first (apparently the Atmel is the best choide) and with the chops aquiered jump to the DSP stuff. I'll have to check if I can get this chips here in the hole of the world.

Thanks for everyone who is contributing this valuable information (and Aron for the forum too)

Luck

Miguel

[bioroids]

Well, it seems there it is one at least http://www.amctools.com/

Very cool

[The Tone God]

I think everyone agrees in starting with uC first (apparently the Atmel is the best choide)...

I will be using Atmel AVR as the platform.

I wonder if there is some kind of simulation soft to check if the code works without building an actual device.

There is. Its called AVRStudio and its availible from Atmel for free. Right now I think the second lesson will be the "Hello World" program. I'll do a software emulated version then a hardware version to teach people how to use both. Also it will allow someone to atleast try their hand at basic uC programming without having to spend money on the inital hardware to decided if they want to go any furthur.

Andrew

[David]

:::Grumble grumble::: Fine! Thats it!!! I'll write a few lessons/articles and see how it goes. Give me some time.

Andrew

P.S. :::mutter:::Screw you guys.:::mutter:::

Oh, give us a break.  You love it!  You want some time?  OK, you have 1000 days.
Uh, that's 8 in binary...

Just kidding...   

[David]

Gents:

We can get a lot of stuff from this dude at reasonable prices.  He's a straight shooter, although I don't care for his politics -- however, that has nothing to do with the topic at hand.  He kept me from making a real stupid mistake when he could have just kept his mouth shut and let me execute my incorrect order, forcing me to repeat it and make him some extra money.

http://www.phanderson.com/ordering_1.html

Spark Fun Electronics is another source for PIC stuff, particularly programmers.  Personally, I've had good luck with my PG2C, which I got on Evilbay for a song.

Also, note that programming languages are available for free:
MPLAB can be downloaded from Microchip's web site.  It's a full assembler IDE.
XCSB is a BASIC variant for PICS.
JAL is a cool high-level PASCAL variant for PICS.

Oh, we'll need a PIC burner program.  The Spark Fun site has a link to download a program called IC-PROG.  Works well.  Trust me on this one.

[bioroids]

Cool, thanks Tone God!

I found the STK500 kit (Atmel AVR) costs here 125U$S plus taxes, and also I found a guy who sells it on Mercado Libre (Argentinian Ebay) for 30U$S used. I'm leaning towars the used kit, but I'm afraid that it's being sold because of not working ok. How can I check that? The guy only used it four times.

Luck

Miguel

[The Tone God]

I found the STK500 kit (Atmel AVR) costs here 125U$S plus taxes, and also I found a guy who sells it on Mercado Libre (Argentinian Ebay) for 30U$S used. I'm leaning towars the used kit, but I'm afraid that it's being sold because of not working ok. How can I check that? The guy only used it four times.

$125 ? Ouch. The current price for a new STK500 (without power adaptor which should cost about $10) at Digikey is $79US.

As for the auction what does he say is wrong ? Got a linky ? You can PM it if you wish.

Andrew