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Leonardo Keyboard

Views:16620Difficulty: 3 Status: Development

32 buttons for a fully-functioning hand-held USB keyboard.

Do you like little buttons? Then let this hand-held keyboard cuddle into your palm. The keyboard is built on top an Arduino Leonardo so you can reprogram to your hearts content. We have pulled out a bunch of pins to make it easily extensible. For example you can make it wireless by hooking up an XBEE or bluetooth module, or interface with any I2C device. This keyboard is built on top of the Arduino Leonardo so it is easy to program and hack!

Images

The Leonardo Keyboard

The Leonardo Keyboard

The lozenge shaped Leonardo Keyboard fits ergonomically into your palm.
Angle Shot

Check out the Leonardo Keyboard chilling at an angle.
Back of PCB

The back of the Leonardo keyboard PCB.
Naked PCB

The PCB before any parts have been added.
3D Printed Keyboard Case

The LEO Keybaord comes with an ergonomically-shaped 3D printed case.
PCB File

Screenshot of the board file for EAGLE CAD software.
Make it Wireless With XBEE

Make your LEO Keyboard wireless by adding one of our 5V XBEE Serial modules or a bluetooth module.
Schematic of Shift Registers

The electrical connections of the shift registers and buttons. This is a screenshot of the schematic file from the EAGLE CAD software.
Atmega32u4 and components Schematic

This schematic screenshot shows the electrical connections around the Atmega32u4.

The lozenge shaped Leonardo Keyboard fits ergonomically into your palm.

Code

Leonardo Keyboard Arduino Code

Here is Arduino Leonardo code to use 4 shift registers hooked up to a total of 32 buttons as a USB keyboard.

Download File

 /* LucidTronix LEO Keyboard * works as standard USB keyboard * Tutorial and details at: * http://www.lucidtronix.com/tutorials/51 *  This code requires Arduino Leonardo */  int dataPin = 4;int clockPin = 5;int latchPin = 6;unsigned long last_press = 0;unsigned long last_key_press = 0;char* letters[] ={"abcdefgh","ijklmnop","qrstuvwx","yz -@#.@" };int leds[] = {7,8,9};int num_chars = 43;int num_registers = 4;byte button_states[] = {0x00,0x00,0x00,0x00};  //01001000int cursor_index = 0;int char_index = 0;char cur_char = 'X';boolean shifting = false;void setup() {  Serial.begin(9600);  pinMode(latchPin, OUTPUT);  pinMode(clockPin, OUTPUT);   pinMode(dataPin, INPUT);  for(int i = 0 ; i < 3; i++) pinMode(leds[i], OUTPUT);  for(int i = 0 ; i < 3; i++) digitalWrite(leds[i], HIGH);  delay(200);  for(int i = 0 ; i < 3; i++) digitalWrite(leds[i], LOW);  }void loop() {  if (millis() - last_key_press > 450) read_keyboard();  if ( shifting ) digitalWrite(leds[0], HIGH);  else digitalWrite(leds[0], LOW);  delay(350);}void read_keyboard(){  //set it to 0 to transmit data serially    digitalWrite(latchPin,LOW);  //while the shift register is in serial mode  //collect each shift register into a byte  //the register attached to the chip comes in first   for (int i = 0; i < num_registers; i++){    button_states[i] = shiftIn(dataPin, clockPin);  }  boolean something_in = false;  for (int i = 0; i < num_registers; i++){        something_in = translate_buttons_2_keys(button_states[i], letters[i]);    if (something_in) last_key_press = millis();   }  digitalWrite(latchPin,HIGH);}boolean translate_buttons_2_keys(byte buttons, char* keys){  for(int i = 0 ; i < 8; i++){     if ( (1 << i) & buttons ){       cur_char = keys[i];       if (keys[i] == '-') Keyboard.write(KEY_RETURN);       else if (keys[i] == '@') Keyboard.write(KEY_BACKSPACE);       else if (keys[i] == '#' && shifting) Keyboard.release(KEY_LEFT_SHIFT);        else if (keys[i] == '#' && !shifting) Keyboard.press(KEY_LEFT_SHIFT);               else if (keys[i] == '|') Keyboard.write(21);       else Keyboard.print(keys[i]);       if (keys[i] == '#') shifting = !shifting;       char_index++;       return true;     }       } return false; }byte shiftIn(int myDataPin, int myClockPin) {   int i;  int temp = 0;  int pinState;  byte myDataIn = 0;  pinMode(myClockPin, OUTPUT);  pinMode(myDataPin, INPUT);  for (i=7; i>=0; i--)  {    digitalWrite(myClockPin, 0);    delayMicroseconds(20);    temp = digitalRead(myDataPin);    if (temp) {      pinState = 1;      myDataIn = myDataIn | (1 << i);    }    else {      pinState = 0;    }    digitalWrite(myClockPin, 1);  }  return myDataIn;}

Parts

parts

Parts

Title	Description	#	Cost	Link	Picture
PCB Leo Keyboard	Printed Circuit Board for shift register based Leonardo Keyboard	1	$7.0	Link
ATMEGA32U4-MU	Integrated Circuits MCU AVR 32K FLASH 16MHZ 44-QFNValue:2.7 V ~ 5.5 V 16MHz	1	$6.04	Link
USB Micro B Female Connector	Micro USB Surface Mount, Right Angle, Horizontal	1	$0.72	Link
Voltage Regulator 3v3 SMD	IC REG LDO 3.3V .15A SOT23 Up to 6V input output 3.3V 150mA (Max)Value:3.3V	1	$0.46	Link
Shift Register	IC STATIC SHFT REG 8STG 16-TSSOP Parallel or Serial to Serial 3 V ~ 18 VValue: Parallel to Serial	4	$0.45	Link
Switch	SWITCH SLIDE DPDT 6VDC 0.3A SMTValue:DPDT	1	$0.44	Link
Button	Tactile switch SMD SPST 0.05A 12VValue:SPST	33	$0.2	Link
Resistor Array	RES ARRAY 10K OHM 4 RES 1206Value:10k	8	$0.12	Link
LED SMD	LED CHIPLED 645NM Red diffuse 1206. Green polarity indicator is opposite of normal.Value:1.8v Red	4	$0.11	Link

Comments:

LordeYaYa

Where is the EagleCAD file for this tutorial? I can't seem to find it anywhere.

Sun, Jan 11 2015 3:04PM

Permalink: http://lucidtronix.com/tutorials/51

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