As we already posted an articles on how to control speed of dc motor using pic microcontroller. But to measure speed of dc motor, we have to measure motors revolutions per minutes. There are many digital tachometers available in market. But all these tachometers are not contactless.

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I inspired to make this project when i need to measure the RPM of DC motor, then I started to make contactless tachometer. Did you use this instructable in your classroom? Add a Teacher Note to share how you incorporated it into your lesson. IR sensor can differ the white and black color, when it is in front of white part it will give output as HIGH and when it is in front of black color output as LOW.

For the measurement of RPM attach a white line over a black part which will attached to axis of motor. Rotating circle is shown is images. We need two circuits 1st is for speed control of DC motor, its very simple circuit but use a good quality motor because magnetic field of dc motor can disturb working of sensor.

After the completing of the circuit and uploading the program, its time to check the output. If you are facing any problem please contact me. I suppose that your tachometer does not works propetly and measure only for half minute. Reply 3 years ago. Reply 2 years ago. Introduction: Contactless Tachometer. By monusuthar Follow. More by the author:. About: i am an electronic lover who want to make something superb. Add Teacher Note.

Arduino UNO 2. IR sensor 3. LCD Display 4. Power Supply 5. Motor for Rpm Measurement 6. We need two circuits 1st is for speed control of DC motor, its very simple circuit but use a good quality motor because magnetic field of dc motor can disturb working of sensor Second circuit is our Tachometer circuit. Attachments techometer. Did you make this project? Share it with us! I Made It!

Electronic Affirmation Mirror by bekathwia in Arduino. Reply Upvote. SB50 monusuthar Reply 2 years ago.


Contactless Tachometer

The Hioki FT and FT are portable, contactless digital tachometers that use reflected visible spectrum light to measure the speed of a rotating object to which reflective tape has been affixed. The instruments can also be used as a contact-type tachometer by attaching the Z Contact Adapter. Contactless performance ensures safety and peace of mind when measuring rotating objects that are recessed inside equipment or whose movement poses a hazard. Simply apply reflective tape to the object being measured, point the instrument at the tape, and press the button. The instrument can detect rotation from a distance of mm while illuminating the measurement location with red light to help you aim it precisely.


Digital tachometer using 8051

A Tachometer is a device which measures the speed of a rotating object like an electric motor or a crank shaft of a vehicle engine. Speed of an electric motor is determined by the number of revolutions made by the motor in one minute. The basic principle behind the Contactless Digital Tachometer involves a simple embedded system with a sensor, a controller and an actuator. The sensor used here is Infrared IR transmitter — receiver pair, the controller used is the Microcontroller loaded with a compiled code and the actuator is a display device, for displaying the speed of the motor. The sensor senses the speed of the motor without actually being in contact with it by the principle of light transmission and reflection and generates a signal. This signal is converted into an electric signal and fed to the microcontroller, which is programmed to calculate the speed in terms of number of motor revolutions in one minute.



The circuit diagram of the digital tachometer is shown below. When viewed through an oscilloscope the collector waveform of the photo transistor Q4 2N would look like this:. Next part is the signal conditioning unit based on the opamp LM IC1. Only one opamp inside the quad LM is used here and it is wired as a comparator with reference voltage set at 3. The job of this comparator unit is to convert the spiky collector wave form into a neat square pulse train so that it can be applied to the microcontroller. Every time the collector voltage of the photo transistor goes below 3.


Contactless Digital Tachometer using 8051 Microcontroller


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