I posted this in the "Motors, Mechanics, and Power" forum but I think it probably fits better here:
This might be a bit ambitious for a first post/first project but here goes... I have multiple guitar amps and a nice MIDI controller (Voodoo Labs Ground Control Pro) and while my GCX looper can control channel/options switching via MIDI, I have to use and entire loop on the GCX for each option which isn't great considering my Mesa Studio Preamp can use 3 alone (channel, EQ, Reverb). So, I thought it would be cool do make a device that does this on it's own. The actual channel/option switch is extremely easy since it just closes or opens a circuit via 1/4" mono jack by connecting or disconnecting the tip from sleeve. My first test can be seen here: http://youtu.be/n7NPA-GzxU4. I used a simple relay schematic from makezine (linked in video comment) and changed the Arduino "blink" code to switch the relay on/off every 3 seconds.
Now, here's the issue... while I feel perfectly comfortable soldering components due to working on guitars (pickup swaps, control changes, etc) my electronics knowledge is EXTREMELY limited. In the last few weeks of tinkering with this design I have learned a TON but still fall short of completely understanding the portion from the 74HC595 on (electrically that is, conceptually I think I've about got it). I keep thinking that I'm missing something... Anyway, I have attached the schematic that I have so far. The funny thing is that I'm unsure of how the LEDs are placed of all things. I find it slightly amusing that I got this far and am tripped up on where and how to put the LEDs in place. But, I placed the LEDs in the only way that made sense to me. Would this work? I haven't decided what LEDs I'm using yet so I put 220 Ohm resistors in for now but will calculate the correct value before building it. Does going through the Darlington Array affect how they're wired up though?
Also, for this type of project, did I choose the right type of relay? I still don't completely understand how solid-state relays work and if they would work in this scenario although I'm leaning towards "no".
One last disclaimer: Everything I've learned about electronics has been what I have read on the internet over the past few weeks. That being said, if there is some HUGE glaring mistake... my bad.
Hopefully the schematic is readable, I'm new to that as well ;)