![\"$_57\"](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2015\/07\/57.jpg?resize=412%2C232&quality=100&strip=all&ssl=1\")
<\/a>They come in wide variety of shapes and sizes. The most commons sizes are 3×4\u00a0and\u00a04×4 and you can get keypads with with words, letters and numbers written on the keys.<\/p>\nYou can even create your own keypad<\/a>\u00a0from scratch.<\/strong><\/p>\n If you follow this tutorial you can control any keypad.<\/p>\n These keypads\u00a0very\u00a0popular among the Arduino tinkerers.\u00a0They\u00a0are very cheap and you can use them with\u00a0any microcontroller (MCU).<\/p>\n You can purchase these modules for just a few dollars. Click here<\/a>\u00a0to compare the membrane keypad<\/a> on several stores and find the best price.<\/p>\n You can use the preceding links or go directly to MakerAdvisor.com\/tools<\/a> to find all the parts for your projects at the best price!<\/p> <\/p>\n A membrane keypad is\u00a0a matrix consisting of rows and columns. Each key is assigned\u00a0to a certain row and column\u00a0(see the picture below).<\/p>\n On a 12\u00a0button keypad you have\u00a04\u00a0rows and 3 columns. The first key\u00a0would make a link between Row 1 and Column 1 (R1C1). 2 would be R1C2, 3 R1C3, * \u00a0R4C1, 9 R3C3 and so on.<\/p>\n You need the following components to make this circuit:<\/p>\n Follow the next schematics. If your keypad is different from the one below, try to search for the datasheet online.<\/p>\n Here\u2019s the library\u00a0you need for this project:<\/p>\n If your keypad doesn’t work with code below you might have to\u00a0change the connections from the previous\u00a0schematics.<\/p>\n Search the web or go to the store that sold\u00a0you the keypad to\u00a0find the datasheet for your keypad.<\/p>\n Note:<\/strong> If your keypad has more keys you can change lines 3 and 4 to add the right number of rows and columns. Then in line 5 you can change the array to match your keypad keys.<\/p>\n View raw code<\/a><\/p>\n In this project when you press a key, it’s displayed the value in your serial montior.\u00a0Here\u2019s what you should see in your Arduino IDE serial monitor when you start pressing the keypad keys.<\/p>\n Now you can create an\u00a0interface for your Arduino using a keypad. You could also add an LCD to this project<\/a>.<\/p>\n I hope you found this guide useful.<\/p>\nDescription<\/h3>\n
Where to buy?<\/h3>\n
![](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/10\/header-200.png?w=1200&quality=100&strip=all&ssl=1\")
<\/a><\/p>\nHow it Works?<\/h3>\n
![\"how](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2015\/07\/how-it-works-keypad.png?resize=594%2C367&quality=100&strip=all&ssl=1\")
<\/a><\/p>\nArduino with\u00a0Membrane Keypad<\/h3>\n
\n
Schematics<\/h3>\n
![\"membrane](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2015\/07\/membrane-keyboard-arduin-tutorial-schematics.png?resize=550%2C273&quality=100&strip=all&ssl=1\")
<\/p>\nLibrary Download<\/h3>\n
\n
Uploading the Code<\/h3>\n
#include "Keypad.h"\n \nconst byte ROWS = 4; \/\/ number of rows\nconst byte COLS = 3; \/\/ number of columns\nchar keys[ROWS][COLS] = {\n{'1','2','3'},\n{'4','5','6'},\n{'7','8','9'},\n{'#','0','*'}\n};\n\nbyte rowPins[ROWS] = {8, 7, 6, 5}; \/\/ row pinouts of the keypad R1 = D8, R2 = D7, R3 = D6, R4 = D5\nbyte colPins[COLS] = {4, 3, 2}; \/\/ column pinouts of the keypad C1 = D4, C2 = D3, C3 = D2\nKeypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);\n \nvoid setup()\n{\n Serial.begin(9600);\n}\n \nvoid loop()\n{\n char key = keypad.getKey(); \n if (key != NO_KEY)\n Serial.println(key);\n}\n<\/code><\/pre>\n\tDemonstration<\/h3>\n
![\"serial](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2015\/07\/serial-monitor-with-arduino-and-keypad.jpg?resize=474%2C334&quality=100&strip=all&ssl=1\")
<\/p>\nConclusion<\/h3>\n