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Switch and Controller MIDI Foot Pedals

 

Switch and Controller MIDI/USB Foot Pedals

This assembled unit converts up to 6 variable potentiometer and  up to 5 switch foot-pedals to an associated MIDI control signal. This unit will work with one, two or up to all 11 inputs, at the same time.

 

This unit can work in standard MIDI mode and via the USB connection. It uses the standard MIDI Baud rate of 31250. The original firmware on the Mega16U2, on the Arduino Uno is replaced to produce a USB-MIDI device (Standard Midi Class). So the unit is USB-MIDI class compliant as shipped.

 

You don’t need to install additional device drivers on Windows, MaxOSX, and Linux, as the firmware acts as a device of Standard Midi Class. It will automatically install on the system as an Audio USB Device.

 

  

*Click to Enlarge*

 

 

 

MIDI&USB Foot Pedals

ITEM#: MIDIUSBFOOTPED

PRICE:  €50.00


 

 

The Switch and Controller MIDI Foot Pedal utilizes:

  • An Arduino board with pre-programmed microcontroller,
  • An assembled  MIDI IN & OUT circuit,
  • 5 inputs for variable potentiometer foot pedals,
  • 5 inputs for switch type foot-pedals,
  • 2 Male Headers x6,
  • 1 Male Header x8,
  • A power-on LED,
  • A 4-way DIP switch which selects the MIDI channel at power-on, see Table 3
  • a MIDI 5-pin DIN input socket
  •  a MIDI 5-pin DIN output socket, 
  • Switch and potentiometer Circuit Schematic Diagram
  • MIDI IN OUT circuit schematic diagram

 

 

The Switch and Controller MIDI Foot Pedal also requires:

 

    

Power Supply:

The  Arduino board can be powered via the USB connection or with an external power supply. The power source is selected automatically. 

  

External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector. A low dropout regulator provides improved energy efficiency.

 

The board can operate on an external supply of 7 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.

   


 

Operation:

At power-on the DIP switch positions are read and the unit will operate in a MIDI channel as shown in Table 3.

  

NOTE: Any unused input Analog Pins on the Arduino should be connected to Ground (GND). Otherwise the unit will produce MIDI outputs due to noise pickup on un-connected Analog inputs.

 


 

Circuit Schematic:

A circuit schematic and the wiring diagram of the MIDI IN and OUT circuit shows the Input/Output connections.  There is also a switch and potentiometer Circuit Schematic Diagram. The pin connections on the Arduino are also available.

 


 

MIDI Wiring:

The MIDI  OUT connector uses a  5-Pin 180 degree DIN sockets. Note that the MIDI IN/OUT wiring is polarised and the correct pins should be used.

 


 

FOOT PEDAL SOCKET WIRING:

There are different types of Jack Socket and Plug connector wiring used for connecting the foot-switches and foot-pedal variable potentiometers.

 

Switch Pedals:

For the Foot Pedal Switch connections a Mono 6.3mm (1/4 inch) Jack Socket is usually used. The Foot Pedal switch wiring diagram is available.

 

Variable Pedals:

Unfortunately there is no accepted standard for the wiring of volume/expression pedals. Different manufacturers wire their equipment in different ways so there is no assurance that a particular volume/expression pedal will work with all equipment.

 

Most models use a Stereo 6.3mm (1/4 inch) Jack Plug with a Tip(T), Ring(R) and Sleeve(S). Some models are additionally fitted with a polarity switch that reverses the polarity of the tip and ring connections on the continuous (pedal) output to increase the chances of compatibility with different devices.

 

Normally the volume/expression pedals utilise a 3-wire stereo  plug, which can be connected,  as shown in the wiring diagram, to the3-wire Stereo 6.3mm (1/4 inch) Jack switched socket.

 

Diagram of wiring for 3-wire stereo plug. This socket can have a ground loop connection (on the socket) to prevent spurious noise pickup producing MIDI output when the volume/expression pedal is disconnected from the socket.

 

However sometimes the volume/expression pedal units can utilize a2-wire Mono 6.3mm (1/4 inch) Jack unswitched socket, and this design requires a resistor connected from the +5 Volt supply to the Analog input pin. This resistor value should be about 1/10 the value of the variable potentiometer.

 

 


 

 

MIDI Pedal Switch Functions:

Switch Input Selections

MIDI Pedal Functions

1  Sustain
2  Sostenuto
3  Soft Pedal
4  Legato
5  Hold 2

Table 1

 

Sustain Pedal: 

The sustain pedal is also known as the Damper Pedal. When operated it sends out a controller value of CC64. When the pedal is pressed ON the unit outputs a value of 127, when released OFF the unit outputs a value of 0. Tone-generators without the 'half-damper' implemented will interpret a value between 0 and 63 as OFF and a value of 64 to 127 as ON.

  

 

Sostenuto Pedal: 

The sostenuto pedal is a type of selective sustain pedal found on acoustic grand-pianos. Pressing down the pedal, sending controller value CC66 with a value of 127, while holding notes on the keyboard will cause these notes to be sustained after you release them. Any notes played after pressing the pedal will not sustain. When the pedal is released it sends out controller value CC66 with a value of 0.

  

Soft Pedal:

The soft pedal works in two simultaneous ways. When the pedal is pressed, sending out controller value CC67 with a value of 127, the sound should be slightly softened in terms of volume and there should be a noticeable difference in the tone-colour of the sound. When the pedal is released it sends out controller value CC67 with a value of 0.

  

Legato Pedal:

When the legato pedal is pressed, sending out controller value CC68 with a value of 127, playing a different note changes the pitch of the current note without re-triggering the attack phase of the envelope of the sound. When the pedal is released it sends out controller value CC68 with a value of 0.

  

Hold 2 Pedal:

The hold 2 pedal is another type of sustaining pedal used fro sounds with two sustain phases in their envelopes. When the pedal is pressed it sends out controller value CC69 with a value of 127, when the pedal is released it sends out controller value CC69 with a value of 0.

  

 


 

MIDI Pedal Controller Functions:

 

Controller Input Selections

MIDI Pedal Functions

1  Volume
2  Modulation
3  Foot controller
4  Balance
5  Expression
6  Pitch

Table 2

 

 

MIDI Volume:

MIDI Volume is used to control the volume level for one MIDI channel. Uses MIDI Control Change numbers CC7 (coarse) and CC39 (fine). Most devices ignore the Fine adjust (CC39) for Volume, and just implement Coarse adjust (CC7) because 14-bit resolution isn't needed for this. In this case, maximum is 127 and off is 0. If using a MultiTimbral device, then each Part can have its own volume.

 

MIDI Modulation:

MIDI Modulation uses MIDI Control Change numbers CC1 (coarse) and CC33 (fine). Most devices ignore the Fine adjust (CC33) for Volume, and just implement Coarse adjust (CC1) because 14-bit resolution isn't needed for this. In this case, maximum is 127 and off is 0. Modulation usually controls vibrato in a synthesiser module.

 

MIDI Foot Controller:

MIDI Foot Controller uses MIDI Control Change numbers CC4 (coarse) and CC36 (fine). Most devices ignore the Fine adjust (CC36) for Volume, and just implement Coarse adjust (CC4) because 14-bit resolution isn't needed for this. In this case, maximum is 127 and off is 0. 

  

MIDI Balance:

MIDI Balance uses MIDI Control Change numbers CC8 (coarse) and CC40 (fine). Most devices ignore the Fine adjust (CC40) for Volume, and just implement Coarse adjust (CC8) because 14-bit resolution isn't needed for this. In this case, maximum is 127 and off is 0.  MIDI balance controls the stereo balance (assuming that the device has stereo audio outputs). If a MultiTimbral device, then each Part usually has its own Balance. 

  

MIDI Expression:

MIDI Expression uses MIDI Control Change numbers CC11 (coarse) and CC43 (fine). Most devices ignore the Fine adjust (CC43) for Volume, and just implement Coarse adjust (CC11) because 14-bit resolution isn't needed for this. In this case, maximum is 127 and off is 0.  MIDI expression can be used as a percentage of Volume, it makes it possible to do crescendos and decrescendos.

 

MIDI Pitch Bend:

The Pitch Bend Change message is normally sent from a keyboard instrument in response to changes in position of the pitch bend wheel. The pitch bend information is used to modify the pitch of sounds being played on a given Channel. The Pitch Bend message includes two data bytes to specify the pitch bend value. Two bytes are required to allow fine enough resolution to make pitch changes resulting from movement of the pitch bend wheel seem to occur in a continuous manner rather than in steps.

   


 

 

DIP Switch Selections

MIDI 

Channel

4 3 2 1
on on on on 1
on on on off 2
on  on  off on 3
on on off off 4
on off on on 5
on off on off 6
on off off on 7
on off off off 8
off on on on 9
off on on off 10
off on  off on 11
off on off off 12
off off on on 13
off off on off 14
off off off on 15
off off off off 16

Table 3 MIDI Channel