MiniLooper by Analog Sound

[gtudoran]

Hey guys,

A little project a pedal looper that will replace the old and heavy TTL based . This one will be much more flexible and much more easy to be build. The core it is a Atmel Microcontroller ATTINY 2313 (you can use any uC from AVR family as log as you modify the code).

So this is the schematic, you have 4 buttons witch represents 4 presets and 5 loops that you can combine in any way you want. The hex file (you need to upload the hex file in the uC flash memory ) is a test/demo version with the following presets:
         RLY 1       RLY 2       RLY3        RLY4          RLY5
SW1:    x             x                            x                x
SW2:                   x             x             x
SW3:    x                            x                              x
SW4:    x             x             x             x               x         

At startup the pedal looper will be in reset state (no relay on), when you press sw 1 you will have SW1 combination, press it one more time and it will be in bypass mode (you can jump to any and from any preset)
To drive the relay i used ULN2003 witch is a darlongton array - be advised that i used 12v relay and LM7805 to get the 5v voltage for the uC. For easy of use you could use 5v relay but you have to use BS170/2n7000 wired as switch bc the ULN2003 have about 1v drop @maximum current so you will end up with 3.5-4v for your relays.

Any question is more then welcomed and i will be glad to help you.

Schematic: http://dl.dropbox.com/u/15275178/AnalogSound-MiniLooper.pdf
Hex file: http://dl.dropbox.com/u/15275178/crisp3.hex

Best regards,
Gabriel Tudoran
Analog Sound

[fpaul]

Dude, this looks b-ass, Thanks!

Not sure when I'll get around to building it, but thanks!

[trixdropd]

Pretty cool! I'm interested in attempting this in the near future.

[gtudoran]

The final firmware will have:
- live programming possibility
- 2 banks with presets (A/B)
- as my friend FiveseveN sugested: 2 mods - stomp mode and patch mode (in stomp mode you can choose witch stomps are active)

Best regards,
Gabriel Tudoran
Analog Sound

[Pigyboy]

Hi Gabriel,
Can you offer the processors pre-programmed? I am in over my head with a project like this but I would love to learn how to build one.
Thanks,
Chris

[gtudoran]

Hi Gabriel,
Can you offer the processors pre-programmed? I am in over my head with a project like this but I would love to learn how to build one.
Thanks,
Chris

Hello Pigyboy, yes i will offer the pre-programmed too but only after it will be finished and tested. The price will be: price for AVR (attin2313) + shipping + a fee that will not exceed 4-5$ for the full code. I think it will be around 10-12$ for a full chip (if i do find some cheaper attiny source then the price will be lower).

Best regards,
Gabriel Tudoran
Analog Sound

[Processaurus]

That looks great, Gabriel.  Very simple!

[gtudoran]

Yap the motto is: Keep it simple , the software is doing all the work.

Best regards,
Gabriel Tudoran
Analog Sound

[potul]

I love the idea of using the ULN2003 as a driver. I might borrow it for a project I have in mind.... 

Do you think an LED could be added to each relay to be able to see what's on?

Potul.

[gtudoran]

Hello Potul,
Sure you can and i believe that is the only way you can do it.

Best regards,
Gabriel Tudoran
Analog Sound

I love the idea of using the ULN2003 as a driver. I might borrow it for a project I have in mind.... 

Do you think an LED could be added to each relay to be able to see what's on?

Potul.