Interface Between The DC Motor and Sensor RE08A

• Optical encoder (Speed Sensor)

Speed sensor is used to measure the speed of the DC motor. This sensor is placed at the rotation of the shaft. The connection of this sensor is shown in Figure below.

• There are plenty of speed sensors that available at the current market. For this project, Rotary Encoder Kit RE08A has been chosen because easy to use, easy to understand. This kit is made to sense the rotation of the DC motor by generating the pulses. These pulses can be translated into the speed of the DC motor by applying a simple mathematical formula which will be added into the programming part. The pulses generated by this RE08A are shown in Figure below and the formula to calculate the speed is shown in Equation below

• Figure above shows that +5 pin is connected to the +5V source. The Gnd pin is connected to the ground. The Signal pin which gives the pulses as output is connected to the counter pin at DAQ through interrupt approach. 
  

• These pulses represent the rotation of the DC motor. We have to count these pulses in one minute to get the speed in rpm. The LabView will measure the time period of the pulse signal. Then, we use the mathematical method to find frequency. 

• Frequency is multiply with 60 because 60 is assume as a 60 second or 1 minute. Then, Divide by 8 because one full rotation has 8 blades.

• Figure below shows the interface between the DC motor and the RE08A. Slotted disc has been installed at the end of DC motor shaft. The wire from DC motor is connected to the power source. In order to control the speed, an adjustable resistor has been connected to the power source which is seeks to adjust the desired speed. The value of speed will appear at the computer screen

Interface between the DC motor and RE08A

    Installation of sensor

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  There are 3 terminal of sensor which is 5V, ground, and signal.5V terminal is generated by function generator in the lab and the ground of sensor is connected to the DAQ ground terminal. Signal that produce from this sensor is connected to the DAQ assist means that DAQ required signal from sensor.