Published March 7, 2018 © GPL3+

A Pocket-Sized Touch Keyboard

A small, Arduino-based physical device that can perform different keyboard operations through capacitive touch sensing.

BeginnerFull instructions provided30 minutes7,791

Things used in this project

Hardware components

Arduino Micro

Jumper wires (generic)

Resistor 1M ohm

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Soldering iron (generic)

Story

It is a small, Arduino-based physical device that can be used to simplify your various keyboard operations. You plug it into your computer's USB port and touch on the capacitive touch sensor. The touch sensor is completely made from scratch, and you can use any metallic objects such as foil, coins, etc. (This works based on the Arduino capacitive sensing library.)

The brain of this project is an Arduino Micro.

Arduino micro

Arduino Micro is the smallest board of the family, easy to integrate it in everyday objects to make them interactive. The Micro is based on the ATmega32U4 microcontroller featuring a built-in USB which makes the Micro recognizable as a mouse or keyboard.

The Micro is a microcontroller board based on the ATmega32U4. It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHz crystal oscillator, a micro USB connection, an ICSP header, and a reset button. It contains everything needed to support the micro controller; simply connect it to a computer with a micro USB cable to get started. It has a form factor that enables it to be easily placed on a breadboard.

Follow the link below to learn more about the board.

Arduino Micro

Note:

you can use only the boards which use ATmega32U4 such as Arduino Leonardo, Leonardo ETH etc.

Circuit diagram:

circuit diagram

Soldering:

Solder the components as per the circuit diagram.

Working:

The Micro is based on the ATmega32U4 microcontroller featuring a built-in USB which makes the Micro recognisable as a mouse or keyboard.

Instead of switches/buttons I decided to add some cool feature to my project, So I used arduino capacitive sensing library to use any metalic object as touch sensor.

The capacitiveSensor library turns two or more Arduino pins into a capacitive sensor, which can sense the electrical capacitance of the human body. All the sensor setup requires is a medium to high value resistor and a piece of wire and a small (to large) piece of aluminum foil on the end.

To know more about how capacitive touch works follow the below link: Capacitive sensing

Pre-requirements:

You need to install capacitive sensing library if you have not installed yet.

You can download this library from here.

Uploading code:

Launch Arduino IDE

Select board

select board

Select port

select port

Upload your code

upload code

What else you can do with it:

unlock your pc witha single tap

play games

The code which I have given in the description(to simplify your sign in) is an example that you can do with it.

You can do more keyboard functions with small modification in the code.

Refer below links to add more keyboard functions

https://www.arduino.cc/en/Reference/KeyboardModifiers

https://www.arduino.cc/en/Reference/ASCIIchart //to use ASCII characters use

     Keyboard.write(ASCII character);

For example to perform space bar operation use following code

Keyboard.write(32); //performs space bar operation

Thank youso much for reading if you need any more information feel free to ask in comments,and I'll do my best answer you.

Code

capacitive touch login device -arduino code

#include <CapacitiveSensor.h>
#include <Keyboard.h>

CapacitiveSensor   cs_2_4 = CapacitiveSensor(2,4); // 1M resistor between pins 2 & 4, pin 4 is sensor pin, add any metallic object such as foil ,coin etc..


void setup()                    
{
   cs_2_4.set_CS_AutocaL_Millis(0xFFFFFFFF);// turn off autocalibrate on channel 1 - just as an example
   Serial.begin(9600);
    Keyboard.begin();
   
}

void loop()                    
  {
 long sensor1 =  cs_2_4.capacitiveSensor(50);
 
   if(sensor1 >= 1000)
   {
  
  Keyboard.print("p@ssW0rD");      //Enter your password here
    Keyboard.press(KEY_RETURN); //Enter key
    delay(150);
    Keyboard.releaseAll();
    }
  }

Credits

Amal Mathew

24 projects • 79 followers

Maker | Not much to boast about – just a human, open-source believer. Simple as that.

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A Pocket-Sized Touch Keyboard

A Pocket-Sized Touch Keyboard

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Circuit diagram:

Soldering:

Working:

Pre-requirements:

Uploading code:

What else you can do with it:

Schematics

Circuit diagram

Code

capacitive touch login device -arduino code

Credits

Amal Mathew

Comments

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