Demo Digital Tachometer 

So finally complete project for digital tachometer published at youtube.  For more information visit    our video at :

https://youtu.be/NJLvhhTuBVc

BUILD, DEBUG AND BURN USING SIMPLICITY

Once Simplicity Studio is installed, the application itself can be used to install additional software and documentation components to aid in the development and evaluation process. Each project has its own source files, target configuration and build configuration such as the debug and release build configuration. To create a project, must click on the project explorer and click Build, the hammer icon on the top bar. Alternatively, go to the project and click build project.

 

Hardware Digital Tachometer

Last Friday, we already complete soldering hardware for digital tachometer based on our Proteus circuit design.  Output of speed (RPM) will display on LCD.

LCD as a output

Toolstick850

Full circuit hardware

Progress of project

Last Tuesday, we design circuit in Proteus VSM.

Circuit designed in  Proteus

For this schematic LCD is use as a output to display the RPM value for speed. This LCD use port 0, so the network resistor is connected to the LCD. This is because port 0 is an open drain, that why we need add network resistor. We also use one push button. Push button use to replace sensor. We connect push button in Port 1.7. In this project we use toolstick850, so the push button connected to port 1.7.

The next day, we start write the coding for digital tachometer in Keil uvison  software. In this coding, first we write name and tittle of our project. After that we write coding to display RPM when push button is pressed.  Digital tachometer have two concept:

• Time measurement - Calculates the speed by measuring the time interval between incoming pulse is known as time based digital tachometer. The resolution of this tachometer is independent of the speed of the measurement and its is more accurate for measuring low speed. 
• Frequency measurement - Calculates the speed by measuring the frequency of the pulse is known as frequency based digital tachometer. The resolution of this tachometer is independent of rotary shaft and its more accurate for measuring high speed.

For this project we use push button to replace the sensor. We need to pressed push button to create the pulse. So, we use concept time measurement because this concept is accurate for measuring low speed. If we use infrared sensor it can catch speed of motor, but the push button use manual handling so cant follow the speed of motor. That's why we use time based digital tachometer.

RPM is revolution per minute.The formula to get RPM value:

num_pulse x period(10ms) x 60

When we run the Proteus, the result:

Result display in Proteus

When the push button is pressed

LCD display  800RPM

LCD display 800 RPM, that means in 10 ms, only 1.33 incoming pulse.

LCD display 1800 RPM

LCD display 1800 RPM, that means in 10 ms, only 3 incoming pulse.

Component use in mini project (Digital tachometer)

List of component:

1) Lcd 16x2
  Lcd use as the output for digital tachometer.

Lcd 16x2

2) Variable resistor

Variable resistor function to adjust the brightness of LCD

Variable resitor 

 3) Toolstick starter kit In this project we need to use toolstick850 silicon lab. The toolstick starter kit(toolstick850) contains the following item:

• Toolstick c8051F850 daughter card
• Toolstick based adapter 
• Usb extension cable

Toolstick starter kit

Component contains in toolstick daughter card :

• Push-button switches
• Current measure jumper
• Power LED
• Potentiometer
• LEDs
• Ic 8051

Component contain in toolstick daughter card

For this mini project digital tachometer, we only use one push button and ic 8051 from the toolstick daughter card.Supply circuit is no need for this project because we use toolstick that already have supply from laptop.

What is tachometer

 The word of tachometer is derived from two Greek word: tachos means "speed" and metron means "to measure". Its  works on the principle of a tachometer generator, which means when a motor is operated as a generator, its produces the voltages according to the velocity of the shaft. Its also known as revolution-counter, and its operating principle can be electromagnetic, electronic or optical based. Power, accuracy, RPM range, measurements and display are the specifications of a tachometer. 

Figure 1: digital tachometer

Digital tachometer types

Digital tachometers are classified into four types based on data acquisition and measurement techniques. Based on the data acquisition technique, the tachometers are of the following types:

• Contact type
• Non contact type  

 

Figure2 :contact type tachometer

 

Figure 3 : non contact type tachometer

Based on measurement technique, the tachometers are of the following types:

• Time measurement
• Frequency measurement

Time measurement 

A tachometer that calculates the speed by measuring the time interval between incoming pulses is known as time based digital tachometer. The resolution of this tachometer is independent of the speed of the measurement and it is more accurate for measuring low speed.

Frequency measurement

A tachometer that calculates the speed by measuring the frequency of the pulses is called a frequency based digital tachometer. This type of tachometer is designed by using red LED, and the revolution of this tachometer depends on the rotating shaft, and its more accurate for measuring high speed. 

About

Bloggers Atikah and Ayuni

The first is who we are and what we doing here? We started a hobby to write a blog a weeks ago because of the assignment mini project in subject micro-controller. We are Nurul Atikah and Nur Ayuni from UniKL BMI Electrical Engineering student(BET). The topic that we get for mini project micro-controller is Digital Tachometer given by our lecturer. The mini project are included:

• Coding of digital tachometer
• Circuit of digital tachometer(in Proteus)
• Hardware
• Toolstick850-B-SK

The progress of mini project will be updated. So, either we success do this project or not, then follows our blog.