Arduino Pageturner

This pageturner connects to a standard dual footswitch - via 6,3mm (1/4-inch) TRS connectors - and a PC using a micro-USB cable.

I use a Boss FS-7 Footswitch, which requires no batteries nor external power supply when used with the pageturner.

The pageturner also works with my Android phone using an USB adapter.

Components

• Arduino Micro
• Pushbutton
• TRS Socket
• 10 kΩ Resistor
• TRS Patch Cable
• 2 Button Footswitch with TRS Socket

Features

• Pushbutton switches modes. While holding it, other inputs change settings.
• Selected mode and settings are stored in the eeprom.
• Onboard LED indicates the selected mode (1-4)
• Serial console with debug output is enabled when the mode button is pressed on startup.

Modes

1. Keyboard: Up Arrow / Down Arrow
2. Keyboard: Page Up / Page Down
3. Mouse: Scroll Up / Scroll Down
4. Media: Volume Up / Volume Down / Volume Mute

Settings

settings can be changed by triggering inputs while holding the mode button:

• Repeat interval change (50ms, 150ms, 500ms)
• TRS input swap (Tip/Ring)
• TRS polarity toggle (Action on low / Action on high)

Wiring

Component	Pin
Mode Button	2
Mode Button Ground	Ground
Jack Tip	4 (= Analog 6)
Jack Ring	3
Jack Sleeve	Ground
Jack Switch	Ground (Jack Sleeve) via Resistor

The switch contact of the TRS socket is connected to ground via a resistor. When the jack is unplugged, the tip contact gets connected to the switch contact. In this configuration, a digitalRead on the pin connected to the tip contact returns LOW, but an analogRead on the same pin is able to detect the slightly higher voltage from the division of the internal pull-up resistor of 20-50 kΩ, and the external resistor of 10 kΩ. The constant inputJackTipAnalogThreshold defines the threshold voltage (10 Bit resolution for 5V) which must be exceeded to detect the unplugged state.

Housing

I put all the components into a small case (dimensions: 80 x 46 x 26 mm) and included a small micro-USB extension cable so there is no stress on the Arduino's USB socket. Using a slightly bigger case is probably not a bad idea...

Usage

Plugged

When the TRS Jack is plugged, following actions are available:

Input	Action
Tip	Keypress / Mouse Wheel / Media Volume
Ring	Keypress / Mouse Wheel / Media Volume
Tip + Ring	Media Mute (Mode 4 only)
Mode	Mode change
Mode + Tip	TRS input swap
Mode + Ring	Repeat interval change
Mode + Tip + Ring	TRS polarity toggle

Unplugged

When the TRS Jack is unplugged, the mode button triggers 'Down Arrow' key presses.