Contactless Tachometer
99 000 RPM Contact-Less Digital Tachometer
Featuring LCD display and automatic DATA hold function
By Ibrahim Kamal
Last update: 14/7/10
This article describes how to build a contact -less tachometer (device used to count the revolutions per minute of a rotating shaft) using a 8051 microcontroller and a proximity sensor.
As the name implies, what makes this device special, is that it can very accurately measure the rotational speed of a shaft without even touching it. This is very interesting when making direct contact with the rotating shaft is not an option or will reduce the velocity of the shaft, giving faulty readings.
This device is built on an AT89S52 (or AT89C52) microcontroller, an alpha-numeric LCD module and and a proximity sensor to detect the rotation of the shaft whose speed is being measured.
A 600 mA.h Ni-Cd battery provides months of regular use of this device before it needs to be recharged. Key Features: Measures up to 99 000 RPM Instantaneous measurement Automatic DATA Hold Function LCD display Ni-Cad Rechargeable battery
Contact less tachometer principle of operation
The idea behind most digital counting device, frequency meters and tachometers, is a micro-controller, used to count the pulses coming from a sensor or any other electronic device.
In the case of this tachometer, the counted pluses will come from proximity sensor, which will detect any reflective element passing infront of it, and thus, will give an output pulse for each and every rotation of the shaft, as show in the picture. Those pulses will be fed to the microcontroller and counted.
To understand how a microcontroller counts pulses, and deduce the frequency of those pulse, please refer to this tutorial about building a frequency meter, that elaborates the process of frequency counting.
The main difference between this tutorial about tachometer and frequency meters, is that we need the reading in pulses per minutes (to count
Featuring LCD display and automatic DATA hold function
By Ibrahim Kamal
Last update: 14/7/10
This article describes how to build a contact -less tachometer (device used to count the revolutions per minute of a rotating shaft) using a 8051 microcontroller and a proximity sensor.
As the name implies, what makes this device special, is that it can very accurately measure the rotational speed of a shaft without even touching it. This is very interesting when making direct contact with the rotating shaft is not an option or will reduce the velocity of the shaft, giving faulty readings.
This device is built on an AT89S52 (or AT89C52) microcontroller, an alpha-numeric LCD module and and a proximity sensor to detect the rotation of the shaft whose speed is being measured.
A 600 mA.h Ni-Cd battery provides months of regular use of this device before it needs to be recharged. Key Features: Measures up to 99 000 RPM Instantaneous measurement Automatic DATA Hold Function LCD display Ni-Cad Rechargeable battery
Contact less tachometer principle of operation
The idea behind most digital counting device, frequency meters and tachometers, is a micro-controller, used to count the pulses coming from a sensor or any other electronic device.
In the case of this tachometer, the counted pluses will come from proximity sensor, which will detect any reflective element passing infront of it, and thus, will give an output pulse for each and every rotation of the shaft, as show in the picture. Those pulses will be fed to the microcontroller and counted.
To understand how a microcontroller counts pulses, and deduce the frequency of those pulse, please refer to this tutorial about building a frequency meter, that elaborates the process of frequency counting.
The main difference between this tutorial about tachometer and frequency meters, is that we need the reading in pulses per minutes (to count