Tech Maker

Sunday, 14 August 2016

Automatic Rain Sensing Wiper Circuit using 555 Timer IC

You have seen Automatic Wiper System in luxury cars where Windshield Wiper automatically gets activated when there is Rain or if there is some water on the windshield. Electronic Wiper is very common device that is attached in every car to wipe the water on the windshield during the rain. But generally they are manually operated and we need to switch them ON manually. But today we are going to build Automatic Rain Sensing Car Wiper System using 555 Timer IC. This circuit automatically detects the rainfall and activates the wiper to clear the windscreen.

Components Required:

555 Timer IC
L293D
IC LM358
Transistor BC557
Resistors (1K, 10K, 2.2M)
Capacitors (0.01uf, 0.47uf)
DC Motor
Rain Sensor
Power supply (5-12v)

Circuit Diagram and Explanation:

Automatic Rain Sensing Wiper using 555 Circuit Diagram

This Automatic Rain Sensing Wiper Control Circuit can be divided into four parts. First part includes 555 IC in Astable Mode, second part includes Comparator LM358, third part has Motor Driver circuitry using L293D and forth part is Rain Detector.

For Astable Multivibraror, we have used a 555 Timer IC for generating pulse in every 2-3 seconds (depends on capacitor value), means 555 Timer IC is configured in Astable mode. Output of Astable Multivibrator is directly connected to inverting pin of Comparator LM358 and Pin No 7 of Motor Driver L293D. Output of comparator is directly connected at pin 2 of motor driver IC. Comparator LM358 IC is used here for comparing 555 timer IC’s output voltage and reference voltage across comparator’s non inverting terminal, set by using Voltage Divider Circuit (R3 and R4). Two LEDs have been used, one at the output of 555 Astable circuit and other at the output of comparator LM358. A Water Detector or Rain Sensor is used for detecting the water or rain. Output of Astable Multivibrator and Comparator is applied to motor driver IC L293D, which will further drive the wiper motor. Whole circuit can be powered using 5v-12v battery depending upon the application.

Working Explanation:

Working of this Automatic Rain Sensing Car Wiper project is simple. As we already explained that this circuit has four parts namely Astable Multivibrator, Comparator, Motor Driver and Rain Detector. When water drops of rain falls over the Rain Sensor then it will trigger the PNP transistor BC557 and PNP transistor turns ON the power supply of whole circuit and circuit start working until there is water on the Rain Sensor. Now after the power supply has been turned ON, Astable Multivibrator starts oscillating in configured frequency.

Automatic-Rain-Sensing-Car-Wiper-using-555-block-diagram

Now when the output of 555 Timer IC goes HIGH then the comparator LM358 gives LOW output and when the output of 555 IC goes LOW then the Comparator’s output goes HIGH. And by using these two outputs DC motor turns clock wise and anticlockwise and wiper attached to it turns right to left and left to right, through Motor Driver IC L293D. That is how the wipers automatically sense rain and gets activated. They remain activated until there is water on Rain sensor, as soon as the water evaporates wipers get stopped. Two LEDs are also used here used for indication. You can see the whole working of this project in the Video below.

Building the Rain Sensor:

Rain Sensor is also called Rain Detector or Water Detector. Although they are easily available on any Electronic Shop or on any Online Electronic Store but you can also build them easily at your home. Here we are briefly explaining the steps:

Step 1: Take Copper Clad Board of approx. 2 inch of length and same width and rub it by using the sand paper.

Step 2: Now take the Black tape or Cello tape and stick it to the Clad board as shown in the diagram.

Step 3: We only need copper tracks under the black tape. So we need to remove all the other copper except under the black tape. For this, make Ferric chloride solution (FECL3), by adding 2-3 tea spoon of Ferric chloride in some water. This solution is called Itching Solution. Put the PCB in this solution for approx. half an hour.

Step 4: Ferric chloride will react and remove the exposed copper and won’t react with the masked copper under the Black tape. Now take out the PCB from the solution without touching the solution and remove the Black tapes.

Step 5: Finally solder two wires on the two created coppers ‘tracks’ as shown in the figure and you have your Rain Sensor ready to use.

SOURCE : Circuit Digest

Design Your Circuits Online for Free with EasyEDA

Design Electronic Circuits Online with EasyEDA

EasyEDA is a Online PCB design and Simulation Tool. We have already covered this tool in detail in this article EasyEDA for Electronic Circuit Design. Today, we will learn ‘How to use EasyEDA’ by designing and simulating the Simple 100 watt Inverter Circuit, with the help of Easy EDA. We have also covered the working and demonstration of this circuit here: 12V DC to 220V AC Inverter Circuit

Before going further let’s talk a bit about EasyEDA, its Online Software used to Design Schematicsfor circuits and to Simulate them and also to Design PCB Layout for the same. It’s basically a tool that is used to design projects. As told its online software, so one need not to download any application for this, you can simple Sign Up or Login to the website and play along, as you please. As its online tool, that makes its platform independent and can be run on any OS (Windows/Linux/Mac) and Browser (Internet Explorer/ Firefox/ Chrome/ Safari).

As no software is being downloaded, no need to be afraid of malware and virus. Once a project is designed, we need not to worry about misplacing it because it will be stored at EasyEDA website. So we can access the file anytime. With many features being added day by day, the EasyEDA website can be depicted as a promising tool for Electronic Hobbyist and Engineers.

Getting Started with EasyEDA:

First to design the circuit we need to go to EasyEDA website: https://easyeda.com. The website is shown in the figure.

Then hit on LOGIN button to create an account. You can create a new Account on EasyEDA or you can Login with your Google or QQ account. Here we are Login with Google Account:

Login with your Gmail details (assuming you already have a Gmail account), and you will see your name on upper right corner.

Drawing the Schematic using EasyEDA:

After creating the account, click on New Project as shown in above figure to start drawing a new schematic. Once you enter the drawing board pick up all the components that are needed from the libraries. If you cannot find the component, click on MORE LIBRARIES option and then search for your component, as shown below.

Pick all the components from the left panel and draw the schematic as shown in below figure. Click on the desired component to select and again click on the canvas to Drop that component. Right click or Esc button to exit after placing component. Wiring can be simply done by dragging the wire between end points of components, like we do in most of the Circuit drawing softwares like Proteus. Also to change the properties or attributes of any components, just click on that component, and change the attributes from the Right side panel.

Short keys can be found and edited in the Blue gear button at the Top. You can try some ‘hand on’ by playing with these examples: EasyEDA examples

After the drawing is completed, Save the schematic under your project name so that you can do the simulation.

Simulating the Circuit in EasyEDA:

After saving the circuit, click on “Green Button” on top of screen for Simulation and choose “Run the document”.

After that you have to configure the simulation you want to run. As shown in below figure, you have five type of simulation.

For now we will stick with transient, as told before we are designing inverter circuit here, the AC output provided by the inverter is to drive home appliances. For that to happen, the inverter circuit should be operated at 50Hz frequency as it is the AC line frequency. We will choose the appropriate START and STOP TIME for the simulation graph to be understandable.

Once the simulation completes you can see the graph at the chosen terminal. The terminal should be chosen by bringing the probe to that point. You can select the probe as shown below; drag it to the point where you want to see the graph.

On simulation you will have a graph as shown below. These waveforms can be saved and exported in different formats like JPG, PDF, PNG etc.

The exported figure shows the Circuit Diagram of 100 watt Inverter using Easy EDA,

Check its full working here: 12V DC to 220V AC Inverter Circuit

PCB layout conversion using EasyEDA:

After we go to schematic board, click on the “PROJECT TO PCB” option as shown in below figure. Once you click on that you will enter to PCB design board. In case if there are any components on the schematic which don’t have PCB traces, you will be asked to choose the most appropriate one to proceed. Choose the appropriate one based on your view and submit it.

After entering the PCB design, all the components will be distributed around the PCB model board as shown below.

Arrange all the components in the orderly fashion as we arrange the books in a shelf. Once everything is arranged you should be having input at one end and output on the other, as shown below.

Now trace the light blue lines on the board without intercepting one another, you can do as many loops as you want. These traces must not be too close to one another.

Once the tracing is completed you will have something as below,

After that choose PRINT in the FILE menu, to get the PCB board trace. Print the appropriate layer by selecting the option, since we are using a single layer, we can leave the configuration as it is.