PIC16F877A Digital Clock

This is PIC16F877A microcontroller based digital clock with 7-Segment display. For this project LTC3710HR was used, however the schematic can be easily adjusted to incorporate larger displays.LTC3710HR is 0.3 inch quadruple digit multiplex common cathode display.Main consideration for choosing the display ...
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Arduino Electronic Lock

Here is another Arduino based design and this time I’ll show you how a 4-Digit Code Electronic Lock can be built with Arduino Mega or compatible boards. For similar design based on PIC16F877 click this link. The I/O I’ve used ...
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Interfacing MAX7219 with PIC16F876 microcontroller

MAX7219 is a common cathode display driver with a simple serial interfaces that can be easily connected to a microcontroller. Among other useful features this IC has built in brightness control and scan control capability that allows to limit the ...
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HC-SR04 Ultrasonic Sensor with Raspberry Pi

Using HC-SR04 Ultrasonic Sensor with Raspberry Pi is a relatively easy task. HC-SR04 is a very popular module that can provide the distance to the object by sending ultrasonic bursts at 40kHz and measuring the time it takes for the ...
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Fading LED with PCF8591 Arduino I2C

Controlling LED brightness with Arduino is one of the basic circuits you can built. Fade sketch is even included in the basic examples in the Arduino IDE. However on Arduino boards it’s done by pulse width modulation, changing the duty ...
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Humidity and Temperature Sensor DHT11 with Arduino

Interfacing Humidity and Temperature Sensor DHT11 with Arduino platform is the topic of this post. I’ve published a number of designs with various temperature sensor, both digital and analog. Here you can see how to use LM75A digital sensor with ...

Digital Power Supply 0-14 Volt

Digitally Controlled Power Supply from 0-14 Volt based on PIC16F876A will be demonstrated in this post. This is a modification of Digital Power Supply 2.5-12V article and has similar characteristics. The most noticeable difference is the use of PCF8591P I2C Digital to ...
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Digitally Controlled Power Supply 2

This is an update to a recent post on a subject of building a Digitally Controlled Power Supply. In part 1 a basic configuration was presented. In this version a numbers of modifications were made to software/hardware to produce a more advanced ...
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Response Time Meter

If you ever thought how fast you can react to external stimulus here is the circuit that can measure your response time. It measures the time it takes for you to press the push button in response to  turning the ...
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Digital Voltmeter VFD Display

This is a new revision of 10 bit Digital Voltmeter. For Arduino based voltmeter click here. Recently I’ve published a few voltmeter designs ranging from a simple LED display voltmeters with 8 bit of resolution to a more complex with 10bit ...