You want to play music from your tablet. It is equipped with MobileSheets or the alike. But your hands are full with flute, keyboard, or cello. So you want to turn the pages with your foot.
There are commercial switches, but they are way over your budget since you are an artist and have to beg for food.
There are modified mouse switches, but you have to place the mouse in a certain position to make it work. And when pressing, the mouse may become visible without reason. This is undesired behavior.
So we want the pedal to behave like a keyboard with only one key: PageDown. There are now mini-keyboards for tablets. Those contain a bluetooth transmitter, and even a battery and charger. Perfect.
Perfect ? No, they don't have a separate PgDn key. Bummer. You have to press a Function key at he same time. Well, that's no problem since we can just short the Function key with a wire. Perfect.
No, after that we cannot pair the keyboard with the tablet. Then we have to press 'normal' keys. But wait: there is an extra switch in the pedal. Great: we use that one to shorten the function key, unless we need to pair the bluetooth devices.
Step 1: Parts
- A sustain pedal or some other footswitch. Cheap machine switches are available for tattoo machines (a few dollars). I used something like this (Ali express) because it doesn't walk away from you when you press it. It also has an extra on/off switch to be used as function-key on the keyboard. Guitar players may prefer a flat switch, but you may have to glue this type to he ground or your foot to prevent it to move away.
- A bluetooth keyboard for your tablet or i-Pad. I used this mini keyboard because it is small enough to glue to the pedal, it has its own battery and charger, and, eehhrrm... it's only 6 dollar (well, I'm Dutch). Unfortunately the 'S' key doubles as a PgDn key when the Func key is pressed. That's why we need the extra switch on the pedal.
- two feet (50 cm) cable with 3 wires if the page-down button and the function-key share a common wire, or 4 wires if they don't. And only 2 wires if you can press the PgDn without a function key.
Step 2: Tools
- blade and Phillips screwdriver
- solder and iron
- drill for the hole through the pedal housing for the cable
- file for the hole for the wire through the keyboard housing
- a small glass (empty)
Step 3: Modify the Keyboard
- Open the keyboard with a flat blade screwdriver
- The on/off switch was covered with a piece of black plastic. It is somewhere on the floor now. Find it, and put it in the glass.
- Locate the connection points on the board
- Cut the wires to the right length.
- Solder the wires to the board.
- File a hole in the top edge of the casing to put the wires through.
- Retrieve the glass from the dishwasher where your wife put it. Get the plastic cover out of the water filter in the bottom of the dishwasher. Put it back over the on/off switch.
- Close the casing.
Step 4: Modify the Foot Switch
- Open the foot switch (5 Phillips screws in the bottom)
- Make a hole in the casing and put the wire through.
- Locate the N.O. or N.C. selector switchRemove all wires except the common between the selector switch and the pedal switch
- Cut the wires to the right length. You have to move the housing over the pedal before closing, so keep some extra length.
- Move the common wire to the center of the selector switch
- Connect the new cable (white=common, green=PgDn, yellow=Function)
- Test the rig.
- Close the casing.
- Glue the keyboard to the top or side of the foot switch. Make sure you can still switch the keyboard on and off, and you can charge the battery after glueing it together.
Step 5: Play !
Well, just a moment ...
- charge the battery with a normal USB charger.
- Pair the keyboard with your tablet. Be sure to SWITCH OFF the selector switch in the foot switch. Press the pairing button on the keyboard, next to the red and blue light. Follow the instructions on your tablet. You may need to enter a number from your tablet into the keyboard, followed by 'Enter'.
- Set the switch back to ON again, shorting the 'function' key. This changes the 'S' button into a 'PgDn' button. Keyboards may differ in this way.
- Test it.
- In MobileSheets, you have to press the pedal once with no effect, after touching the screen. After that, the page turns (or scrolls) every time you press the pedal.
If you forgot step 5, the pedal doesn't work the first time after touching the screen.
Have fun !