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An Arduino Decoder

Building organ consoles for use with Hauptwerk, adding MIDI to existing consoles, obtaining parts, ...
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An Arduino Decoder

PostTue Feb 19, 2019 6:26 pm

I am clearly on a roll. If an Arduino can act as scanner, it can also act as a decoder. The code, available on my website ... no-decoder

accepts MIDI input and turns up to 68 output pins on or off. A pair of parameters can be redefined to make the unit respond to any channel desired. This decoder may be of use to anyone wishing to add a rank or two of pipes to their HW setup.

Of course, since an Arduino output is only good for 40 mA max, drivers are needed. I tried the following unit: ... 520-MOSFET

and had a small solenoid clicking away quite happily every time I played B.

Of the 7 connections on the module, only 3 are needed. The modules must share a common ground either using the pin marked GND or the screw connection marked GND. This ground must also connect to ground on the Arduino and the ground of the 12 V power supply. The output pin on the Arduino goes to the pin marked SIG. The return line from the chest magnet connects to the V- screw connection. There is no need to bring +12 V out to the driver module. Keep all the +12V wiring in the chest along with the spark suppression diodes which are of course critical.

If these modules look "space hungry" I have a way of neatly mounting 63 modules on a standard 12 inch by 7 inch prototyping board. If anyone is contemplating doing this, let me know and I'll put some pictures on my website showing how it's done.

Each module has an LED to indicate when it is active, a nice touch, as well as a pull down resistor on the gate to keep things turned off as the Arduino fires up. And at about a dollar apiece, the price is right.

There are many excellent decoder/drivers out there at reasonable prices.
This post is aimed at those who prefer to "roll their own."

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