Passive MIDI Selector Switcher

While dealing with music production it could happen that you want to send your MIDI inputs from more than one peripherals to the same destination. This could be the case if you have a nice MIDI keyboard on one hand and a MIDI drum pad controller on the other and you want both to comunicate with your favourite DAW.

So the question is: how can you manage all those inputs? The simplest solution is to unplug the MIDI cable from the connected MIDI device and plug that of the desired one. It's free, it's simple and, how can I say that... tremendously tedious!

Another solution could be the use of a MIDI merger box. These circuits allows the simultaneous use of various MIDI input devices, which is great. They have some drawback anyway: they are generally limited to two inputs, inevitably introduce some lag (this is always true when a microcontroller is added to the equation, but particularly present in "serial" applications like MIDI), they are expensive and in the need for a power source.

The third solution is simple, cheap, someway "old school" and, as far as you are not in the need for more than one MIDI device working at the same time, noteworthy: a mechanical selector.

In this instructables I will show you how I built a simple mechanical MIDI switcher/selector. I will also share with you Gerber files to have the PCB manufatured by Professionals and then have it ready to rock in the shortest time possible.

Let's go!

The device is made up of only few components. It is also very easy to assemble.

Follows the bill of materials (BOM):

1x Passive MIDI Selector PCB

5 x MIDI DIN 5 connectors

1x Triple Pole Four Throws (3P4T) single deck rotary switch

4x PCB spacers

Some centimeter of solder wire, a soldering station and 15 minutes of spare time...

Nothing more! :)

>>HERE<< is the MIDI Selector's PCB Gerber files link (Github).

My projects are free and for everybody. You are anyway welcome if you want to donate some change to help me cover components costs and encourage the development of new projects.

>>HERE<< is my paypal donation page, just in case you want to push the development of new projects ;)

The MIDI selector simply puts into electrical contact the MIDI device plugged to MIDI_A connector to devices plugged to MIDI_B, or MIDI_C, or MIDI_D, or MIDI_E.

You can think at this selector as a 1 input to 4 outputs switcher: in example, switch up to four master devices (keyboards, sequencers, drum pads etc etc) sending MIDI messages to your favourite DAW.

The MIDI selector does not merge two MIDI signals into one! It's a simple switch, not a MIDI merger.

Alternatively you can use the selector as a 4 inputs to 1 output MIDI switcher: the same MIDI input (i.e. master keyboard) can be sent alternatively to up to four synthesizers.

The MIDI selector does not multiply a MIDI signal sending it to more destinations at the same time! It's a simple switch, not a MIDI Thru.

It's fully passive, so you don't need any power source to have it working.

Please, notice that all three signals coming from MIDI (5V, MIDI message and ground) are switched. In principle, ground could be left common to all devices, but I have experienced unexpected behaviours when connected MIDI devices where left unpowered. With all three signals switched you will be 100% sure that unwanted interactions between devices will not arise.

The MIDI selector PCB pictured in this Instructables was sponsored by JLCPCB, a high-tech manufacturer specializing in the production of high-reliable and cost-effective PCBs.

Their customer service is very good and PCBs a great value for the money!

Without their contribution this project would likely not have been realized so many thanks!

Subscribing to their site through this link (affiliated link) gives you access to a series of welcome coupons for your orders. Subscribing costs nothing, so it's a great opportunity to try their services at the lower cost ;)