Mission LCD Looper (semi-digital effects bank switching?)

[Kevin Mitchell]

I guess the title would be a good name for such project 

Let's start with the vision. Lets say;
- 7 switch looper (or a/b switch as it's called?) and a main volume expression.
- 8 effects to plug (16 in/out +2 for the vol exp.)
- a multi-line LCD display + select controls to view/edit saved banks (7 banks)
- means to save/store banks even when not powered (internal battery to chip?)
- a single/mix line switch to mix appropriate banks (can not/should not mix banks using the same pedal lines)

Based off of ease and practicality, what would serve well as a memory bank for such project? I seem to be leaning towards arduino due to popularity. But to be honest I don't know where to begin.

I see ideas like this all of the time. There's bountiful information on this forum and many alike. But I've decided to start this thread for clarity and hopefully an end project to share. So I have a list of questions I hope some of you fine folk may answer or provide useful links to indulge.
I have in the passed learned a few programming languages (VB, Java and a couple others) and I am quick to learn/catch on. So I'm not intimidated by programming but much more the concept of this project all together.

A good friend of mine and his father have experience with arduino boards and have built things like a 3D printer and a small milling machine and some other strange workshop gadgets. I'm sure they'd happily lend a hand even though this may be a different realm of thought.

So here's what I believe I should do;
Using switching circuits such as this one published at Geofex I believe for a memory/controller it would have to activate triggers based off the saved effect-banks. This makes it sound very simple for my taste but I'm very up in the air about this said "controller/memory/trigger activator" with LCD display&controls -which I cannot yet wrap my head around.

I feel I should start from scratch for the ultimate experience and full final product of this vision. I'll come back here with thoughts and information to add. I am aware that topics like this come up almost once a month so I apologize for any repetition.

To start I'll be playing with the controller,LCD and programming as soon as I have a foot in the door.

Sorry if I ramble    Thanks everyone!

[PRR]

Divide and conquer.

The obvious split is the signal-box and the brain-box.

The jacks, switching, etc can be built and debugged alone, using jumpers or DIP-switch to emulate the brain-box signals.

On another bench, the brain-box with user interface and output to signal-box can be debugged with LEDs to show what signals it is sending.

[Kevin Mitchell]

It's the brain box that I'm clueless on right now. I'd need a board or chip that can communicate with a few controls and an LCD (through programming of course) that can trip (or serve as) a trigger (many triggers) for the signal/effects switching circuit and save the selected states. Perhaps all of this can be done through programming alone. But what board/chip could do this?

It's all on the brains really...

Thanks for the tip! Good pointer with all the breadboarding ahead of me...

To further explain, the switching circuit from Geofex uses <3.5v for position one and when the trigger goes above lets say 6v it trips the switch. Having that in mind I'm imagining a board/chip with many trigger outputs and a memory bank (like 6-8 banks) to save which outputs (or triggers) are active based on a saved state.  Did I lose anyone? 

I'm hoping my concept isn't thrown off too bad by what is obviously obtainable. It's definately not out of the realm of possibility.

Once I find the right brain it'll all come together.

[Kevin Mitchell]

I've decided to try an arduino board. With one I could program the display, controls and memory banks as well as the switching circuit's triggers.

From what I've been reading I could possibly use the outputs on a typical ARDUINO UNO board (with result of what I'll program) as triggers -toggling the appropriate voltages to the switching circuit. This would be a simple method with no sub-boards for the arduino needed.

I feel I've learnt plenty for the day. This seems much more clear to me.
Now I'm trying to find a replacement for the 4053 switching IC with one with more channels. If you have anything to suggest please share! It may be possible to program the switching and relays all together. But that would mold my original idea to an uncomfortable angle and would still have to use a sub-board. Though it would make adjusting effects orientation possible. We shall see where the road leads.

Now I see it's the programming/writing that'll be the big stretch.

Anyone with such knowledge or experience please feel free to chime in!
Back into the wormhole I go.

[PRR]

> I'd need a board or chip that can communicate with a few controls and an LCD (through programming of course) that can trip (or serve as) a trigger (many triggers) for the signal/effects switching circuit and save the selected states. Perhaps all of this can be done through programming alone.

I'm a cave-man. But even I know that a PC with a printer port can display stuff on screen, get input from user, store settings, and set port bits high/low.

These days the $39 Raspberry Pi plus an LCD does all that, maybe more than you need.

A $39 BASIC Stamp will interface buttons, drive an LCD, and flip port bits. IIRC it also has small non-volatile storage? And writing BASIC is about the shallowest learning-curve around. But it is sneered-on by modern (post 1975) geeks.

[Kevin Mitchell]

Pi seems friendly to a few programming languages - java as well.

I guess arduino is java friendly too and is $25 for the UNO board.

This is new territory for me - so many new toys. Now knowing what I can do and the fact I can use a familiar language I'm very stoked. I used to love programming. The same ambition brought me to DIYing stompboxes 

The first programming language I learned was visual basic when I was 14. If basic is anything like that then I agree. Very shallow curve lol.

[slacker]

The digital side should be doable with an Arduino, it's all pretty simple stuff and the using an Arduino means there's loads of resources and tutorials on the web for everything you need to do. For a screen I would go with a HD44780 LCD these are cheap and have plenty of Arduino support. For saving patches you can use the Arduino's built in EEPROM, this is will store data when powered off.

The only issue you might have is not having enough pins to do everything you want but there's ways round that using shift registers or other "expander" chips.

[Kevin Mitchell]

There's something called an I2C bus I believe that works for the LCD with it's own library. It only needs 2 control pins to the arduino then power and ground.

I have considered that I would run out of control pins if I get too crazy with the relay such as effects position in the bank's chain. I'll have to find a sub board or means to expand the arduino's pins. I've read an article about using a 4053 I think? But it can only read or write one of 8 inputs/outputs at once.

I've sourced some LCDs that I am fond of. Multi-line, white characters and a black background for cheap. But it would be coming from china.

Much to learn.

[Kevin Mitchell]

Just placed a few orders.

A few LCD displays (arduino compadable) at $3 each
A few I2C boards for the displays at $1 each -some displays come with this on the back side but I'm saving a some cash here-
An Arduino Uno board $30 after shipping

Just need some controls, like spst tactile ones. But I'm probably going to improvise until the actual build/boxing. Any ideas on that are very welcome!

I am still concerned about running out of outputs on the arduino but I'll worry about that when the time comes.