Tech Lab: Find out the total ON time and total OFF time of an LED, by simulating a street light system.

Objective:

Find out the total ON time and total OFF time of an LED, by simulating a street light system.

Design the front panel as shown in the fig.

Apparatus Required:

Procedure:

Connect the component as per the circuit diagram shown above.
Connect the USB cable of DAQ to one of the USB ports of the PC.
Open the LabVIEW software and create a new VI. Bring the DAQ Asst function into the block diagram by right clicking over it go to Express------>Inputs-------->DAQ Asst.
Select the proper channel of the DAQ as Acquire Signals------->Analog Input------->Voltage------>AI 0 then click on finish.
A configuration window will be opened and change some parameters in the configuration window such as:

Voltage range (max=5, min=0)

Terminal configuration (RSE)

Acquisition Mode (Sample on Demand), then click on OK.

A ‘DAQ Asst’ function block will appear on the block diagram and it has an output variable named ‘Data’. It has an outward arrow (input for the VI) means the data acquired by the DAQ is ready for further processing in the VI.
The value of the variable ‘Data’ is the real time data in Voltage.
Observe the value of voltage when the LED is ON (dark over the LDR) and OFF (light over the LDR).
Create Boolean indicator and design a logic to reflect the status of physical LED over the Boolean indicator.
Now find out the total ON time and OFF time of the LED. And there should be an indicator named ‘Process Time’ which is the algebraic sum of ON time and OFF time.

Tech Lab