Heart rate monitor using 8051

In this article we are listing all the projects and circuits we have developed using the 8051 micro controller. We have tested all of these projects in our lab and verified the working . All these projects are made to solve a real world requirement or problem. Engineering students & other diploma students will find these projects useful for their mini project and main project requirements.
All the 8051 projects listed below are made using the 8051 compliant microcontroller from Atmel – AT89S51.  We have given the correct circuit diagram, working and software code (in assembly language) for each and every project. You can use all of them freely for your project & learning requirements. In case you are using a controller other than AT89S51 – please be sure to check the hardware of your controller and compare it with that of AT89S51. This is necessary because we have developed all the software in assembly language. If you are not that good at assembly language, you can convert the software into C language & use it with any compliant  8051 controller.

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1. Ultrasonic Range Finder using 8051 – This project as the name says, is an application to measure distance of an object. It uses an ultrasonic transducer module HC-SR04 to measure the distance and the controller AT89S51 to make the necessary processing. This project can be used to make applications like Automotive parking sensor, Obstacle warning systems, Terrain monitoring robots etc. This ultrasonic range finder can measure distances upto 2.5 meters with an accuracy of 1 cm.
2. Digital Tachometer using 8051 –  This project is a digital tachometer which can be used to measure the revolutions per second of any object like a rotating wheel or a disc or a shaft. This application built using 8051 micro controller can measure upto 255 revolutions/second with an accuracy of 1 rev/sec. This application has 3 important sections – 1) is the optical pickup designed to pick the revolutions of the object using a photo transistor and LED. 2) is the processing stage designed using 8051 and the associated software 3) is the display section using 7 segment displays.
3. Water Level Controller using 8051 –  This is one of the most popular project we have published using 8051 controller. This water level controller monitors the level of the over head tank  and automatically switches on the water pump when ever the level goes below a preset limit. The level of the over head tank is indicated using 5 leds and the pump is switched of when the over head tank is filled.  We have given an illustrated circuit diagram with working explained in detail. You will also find the software codes written in assemble language.
4. Voltmeter using 8051    - We all must have used a multimeter from our young days. Have you ever bothered to create one ? So here is one such an interesting project. A Voltmeter using 8051 micro controller. Even though its quiet simple and an easy to make one, you shall find it really interesting. This can be used as an application at the mini project level for engineering and diploma students. This digital voltmeter  can measure 0 to 5 volts and 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. ADC0804 is the ADC and AT89S51 is the controller used in this project.
5. Thermometer using 8051 - This is an interesting project designed to measure temperature using 8051. Its a simple 0-100°C digital thermometer with 1°C resolution using 8051. The circuit is based on LM35 analog temperature sensor, ADC0804 and AT89S51 microcontroller. LM35 is an analogue temperature sensor IC which can measure a temperature range of -55 to 150°C. Its output voltage varies 10mV per °C change in temperature.
Knowledge Resources:- The articles below given are basics on how to work with 8051 micro controller. You can refer them if you come across a road block anywhere!
1. Interfacing 7 segment display to 8051 – A good tutorial on interfacing 7 segment display to 8051 micro controller.
2. Interfacing LCD display to 8051 – Explains how to interface a 16×2 LCD display with 8051 micro controller.
3. Interfacing DC motor to 8051 – Explains how to interface a DC motor with 8051 micro controller.
4. Interfacing push button switch to 8051 – Interfacing LED & Push button switch to 8051 micro controller.
5. Interfacing ADC to 8051 – This articles gives you a good detail on how to interface ADC to 8051 micro controller. ADC 0804 is used to explain the interfacing procedure with an example software routine.