Midi controlled relay

[Guest chrishandcock]

Hi

All i'm trying to do is take a midi output from my computer. it does not matter what note or signal it is.

It needs to trigger a realy when any midi signal is sent to it.

Really simple i think, but i know absolutly nothing about midi.

Can anyone help with somthing that would do it, or a simple circuit.

I am looking for a cheap, easy option.

Thanks

Chris

[lylehaze]

That depends on the size and type of relay, and how many relays you'd like to control.

Also, will your core be doing anything else? That will help determine which connectors might be free to do this with.

Let's start with the hardware.  There are regular relays that are controlled by a coil of wire making a magnetic pull on the contacts. We could drive one of these, but MOST of them (not all) need more than 5 volts to work. Another problem is when you turn it off, the magnetic field "breaks down" and puts an electrical spike on the driving pin, usually doing some damage to the chip or transistor driving the coil. Also, getting enough current to drive the relay will probably require some sort of driver or transistor.

So do we get to choose the relay? that could solve some of these problems, but it leaves you with a hard-to-find relay type and size.

The easiest way is to get a "Solid State Relay". These can be sized for most AC or DC loads, and they usually have a LED input that takes just a few volts and little current to operate. These things to all the work for you, and they isolate your MIDIBox from the nasty stuff. If you just want a few, you could drive them straight from the MIDIBox, or if you want more you could drive them from a DOUT module. A typical DOUT module has 32 outputs, I think. Multiple modules offer even more outputs to do this with.

Where are you from? If you are in the US I can offer some sources for solid state relays, if you tell me what you are driving with them. AC voltage? DC? How many amps of current?

Once we answer the hardware questions, driving them from MIOS should be pretty easy. :-)

LyleHaze