MIDI projects

[jokke]

Sry. not really a stompbox but close.

I was just wondering if someone has experience of these great midi projects at http://tomscarff.tripod.com/

I have googled and searched but this is the only site that has a midi-relay control project. I'm interested about this http://tomscarff.tripod.com/prg_chx8/program_change.htm . Can someone explain how that controls the relays?

-Jokke

[Fp-www.Tonepad.com]

I have seen that site, and I think the projects are very simple and nice. Hopefully I'll get around to experimenting with PICs soon. Keep us posted if you decide to build anything.

Fp

[hamer267]

Sry. not really a stompbox but close.

I was just wondering if someone has experience of these great midi projects at http://tomscarff.tripod.com/

I have googled and searched but this is the only site that has a midi-relay control project. I'm interested about this http://tomscarff.tripod.com/prg_chx8/program_change.htm . Can someone explain how that controls the relays?

-Jokke

O/P 1 thru 7 are used to drive a transistor or FET which would control the relays. The PIC itself cannot supply enough current to drive the relays, so a driver transistor is required. Here is a schematic:
http://tomscarff.tripod.com/relay_changeover/rly4coct.gif
This shows a SPDT relay. You may want to use a DPDT for true bypass.

I have one breadboarded and it works well. I think the final design will use separate PCB for each relay/loop so the audio path is a short as possible and also provides for isolation from the digital signals. The relay/loop modules will be normallized in pairs. I may use one of the outputs for a "juggler" that changes the order of two of the loops.

[jokke]

Are the switches (record & sw0-7)  latching or unlatch?

[Carlos]

http://www.jimkim.de/html/guitar01_01.htm

Regards

Carlos

[jokke]

http://www.jimkim.de/html/guitar01_01.htm

Regards

Carlos

Some questions, if here's someone who can answer.

The relays: Does the NPN:s cut the ground from the relays? Or what is the idea of the relay control?

What are the "N.C." in the optocouplers pins 3 & 6?

-Jokke

[NeveSSL]

Jokke... I am definitely interested in doing this same thing.  Would you like to work together?  I'm afraid my electronics knowledge is not the greatest, but I am more than willing to learn and I generally am able to learn quickly.    I've been looking for some PIC programmers now and what not.  Let me know what you've found and maybe we can build one or two of these together.    Thanks!

Brandon

[The Tone God]

The relays: Does the NPN:s cut the ground from the relays? Or what is the idea of the relay control?

The NPN transistors connect the coil in the relay to ground while the other end of the coil is already connected to power thus powering the relay. My guess is it looks like non-latching relays to me.

What are the "N.C." in the optocouplers pins 3 & 6?

N.C. = Not Connected

Andrew

[12afael]

I build a midi drum .from another page.
on www.ucapps.de you can find a lot of projects. there is a midi control pedal I think.

proteus is a great simulation software for pic based circuits. you can charge the program on the chip and simulate together with the rest of the crcuit.