Object counter using 8051

admin January 23, 2018 27 Comments
Object counter using 8051 microcontroller. This article is about a simple object counter/visitor counter using 8051 microcontroller . AT89S51 belonging to the 8051 family is the microcontroller used here. This circuit can count the number of objects passing across a line , number of persons passing through a gate/door and so on. The can be simply divided into two sections i.e. the sensor section and the display section. Sensor. The sensor part consists of a ultra bright led (with...
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alcohol detector circuit

Breathalyzer circuit using 8051

admin July 21, 2018 22 Comments
We all see Police using breathalyzers on drivers to check if they are under the influence of alcohol. Drink & driving is a crime in all countries. But do you know that this machine is easy to make? Here is how to DIY alcohol breathalyzer with 3 digit display output. Alcohol Breathalyzer circuit using 8051 microcontroller (AT89S51) This article is about a breathalyzer circuit using 8051 microcontroller which outputs the blood alcohol content (BAC) from the breath. The BAC...
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Heart rate monitor using 8051

admin January 23, 2018 104 Comments
This article is about a simple heart rate monitor using 8051 microcontroller. Like the previous 8051 projects, AT89S51 is the microcontroller used here. The device senses the heart rate from the finger tip using IR reflection method and displays it on a three digit seven segment display in beats per minute. The circuit has an accuracy of 4 beats per minute and it is very easy to use. In medical terms, the technique used here for sensing heart rate...
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Interfacing hex keypad to 8051

admin March 8, 2013 17 Comments
This article is about interfacing a hex key pad to 8051 microcontroller. A clear knowledge on interfacing hex key pad to 8051 is  very essential  while designing embedded system projects which requires character or numeric input or both. For example projects like digital code lock, numeric calculator etc. Before going to the interfacing in detail, let’s have a look at the hex keypad. Hex keypad. Hex key pad is essentially a collection of 16 keys arranged in the form...
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8051 Microcontroller Projects & Circuits

admin November 2, 2017 48 Comments
This article is a compilation of all 8051 based Electronic Projects and Circuits we have developed at CircuitsToday till date. We have one of the biggest collection of 8051 based Projects – which range from very Advanced one’s like Electronic Voting Machine, Heart Rate Monitor, RFID based Access Control (and a lot more) to Medium Level and Easy one’s like Water Level Controller, Solar Panel Tracker, Ultrasonic Range Finder etc. Note:- We have listed Project Kits of all our...
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Ultrasonic range finder using 8051

admin October 31, 2017 84 Comments
Ultrasonic range finder using 8051 . A simple ultrasonic range finder using 8051 microcontroller is presented in this article. This ultrasonic rangefinder can measure distances up to  2.5 meters at an accuracy of 1 centi meter. AT89s51 microcontroller and the ultrasonic transducer module HC-SR04 forms the basis of this circuit. The ultrasonic module sends a signal to the object, then picks up its echo and outputs a wave form whose time period is proportional to the distance. The microcontroller...
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Digital tachometer using 8051

admin April 20, 2015 44 Comments
Contactless digital tachometer using 8051. A three digit contact less digital tachometer using 8051 microcontroller which can be used for measuring the revolutions/second of a rotating wheel, disc, shaft or anything like that is introduced in this project. The tachometer  can measure up to a maximum of 255 rev/sec at an accuracy of 1 rev/sec. What you just need to do is to align the sensor close to the reflective strip  (aluminium foil, white paper or some thing like...
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Random number generator circuit

Random number generator using 8051

admin July 21, 2018 9 Comments
DIY Random number generator A  random number generator using 8051 that displays a random number between 0 & 99 is shown in this article. The circuit itself is very simple and may not find any applications in serious embedded projects and this article is just an illustration. The circuit is based on AT89S51 microcontroller, two seven segment LED displays, two transistors and few passive components. Circuit diagram List of components Microcontroller (AT89S51) – 1 nos Push button switches –...
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Voltmeter using 8051

admin October 4, 2012 16 Comments
Voltmeter using 8051. A simple 0-5V voltmeter using 8051 is shown in this article. This digital voltmeter has a sensitivity of  200mV which is a bit low but this project is meant for demonstrating how an ADC and seven segment display can be interfaced to 8051 to obtain a digital readout of the input voltage. A 31/2 digit high end voltmeter will be added soon. ADC0804 is the ADC and AT89S51 is the controller used in this project. Before...
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Interfacing ADC to 8051

admin September 6, 2012 10 Comments
ADC (Analog to digital converter) forms a very essential part in many embedded projects and this  article is about interfacing an ADC to 8051 embedded controller. ADC 0804 is the ADC used here and before going through the interfacing  procedure, we must neatly understand how the ADC 0804 works. ADC 0804. ADC0804 is an 8 bit successive approximation analogue to digital converter from National semiconductors. The features of ADC0804 are  differential analogue voltage inputs, 0-5V input voltage range, no zero...
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