4×4 Matrix Keypad

Tired of using normal push buttons as input to your system? You should consider including a matrix keypad. Matrix keypad is widely use in our daily life. Often, matrix keypad is available in 3×4 or 4×4. For your information, matrix keypad is a good substitution to normal push button. Matrix keypad offers more input to the microcontroller with lesser I/O pins required as compared to buttons. Consider your system needs 16 inputs, you requires only 8 I/O pins with keypad instead of 16 I/O pins. So you can actually use the extra 8 pins for other functions. Continue reading “4×4 Matrix Keypad”

DIY Printed Circuit Board (PCB)

Today we going to discuss on how to make your own printed circuit board (PCB). Making a home-made PCB is easy with toner transfer method. But first, let us understand more what is a PCB. A PCB is used to mechanically support and electrically connect electronic components using conductive pathways.

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RF Module (Part 2)

If you haven’t check on the first part on RF module explanation, you might want to read it before proceed with RF using library. Here we going to discuss how to implement VirtualWire library with low cost RF module. VirtualWire library does not use the Arduino UART pin (digital pin 0 and digital pin 1).

You can download the VirtualWire library here.

Before we look into the code, let us see some of the functions.

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Voltage Regulator LM7805

Voltage regulator is a device used to provide a constant output voltage. Most of the circuits uses 5V supply. With a voltage regulator, LM7805 you can make your own 5V supply easily.

Lets look at voltage regulator 78xx family. The xx specifies the output voltage of voltage regulator. For example, 7805 means 5V output voltage, 7812 means 12V output voltage. There is also 79xx family which provides negative output voltage. 7905 would provide a -5V output voltage.

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