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Automatic Washbasin Tap Controller

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    First published on: 1-12-2005

    Automatic Washbasin Tap Controller

    Akshay Mathur and Abhay Mathur

    Make your washbasin tap work automatically when you put your hands just below the water tap outlet. This infrared-based system detects any interruption of the IR rays by your hands or utensil and water automatically starts flowing out of the tap.

    The circuit is built around 555 timers and comprises transmitter and receiver sections. Both the transmitter and the receiver work off 5V DC. The IR rays continuously emitted by the transmitter fall on the receiver. As soon as an obstacle comes in between the receiver and the transmitter, interrupting the IR rays, the output of the IR sensor goes low momentarily to trigger the timer circuit in the receiver and water comes out for eleven seconds through the tap.

    Fig. 1: Transmitter circuit
    The transmitter is built around timer IC 555, which is used as an astable multivibrator to generate around 38 kHz frequency (see Fig. 1). The timer output is fed to transistor T1, which drives the IR LED (LED1). Note that IR LED1 must be properly oriented towards the IR sensor module of the receiver circuit. Its transmission wavelength of 900 to 1100 nm lies in the peak receptivity range of TSOP1738 receiver module.

    The receiver circuit comprises the sensor module, monostable timer and relay driver circuit (see Fig. 2). The sensor module TSOP1738 is sensitive to IR radiation modulated at 38 kHz. Its normally high output goes momentarily low when any IR radiation is detected or interrupted.

    Fig. 2: Receiver circuit
    When IR rays falling on the receiver are interrupted, the sensor output goes low momentarily to trigger timer IC2. The output of the timer goes high for eleven seconds and the relay drives the solenoid. During this time period, energisation of the solenoid lifts up the valve fitted in the pipe to let water flow out of the tap. Solenoid valves used specifically for this purpose are shown in Fig. 3.

    The relay driver circuit consists of resistor R8, transistor BC548 (T2) and free-wheeling diode D1. Diode D1 protects the relay from damage by high voltages generated by the back emf when the relay is de-energised.

    The time period for which the timer goes high can be calculated as follows:
    Ton=1.1 R6C5=1.1×100×103×100×10–6=11 seconds

    Fig. 3: Mains 230V AC 2/2-way semi-pilot,diaphragm type, solenoid valves
    Use shielded wires or leads for installing the IR LED and the IR sensor at opposite sides of the washbasin. Install the IR LED and IR sensor around half a metre apart such that the IR rays transmitted by the IR LED directly fall on the IR sensor. Now switch on the power supply to the circuit.

    When you put your hands between the IR LED and IR sensor, the relay energises to make the solenoid open up the valve and water flows out of the tap.


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    commentPost Comment | 16 Comments

    prince   964 days ago

    how can i use this project at home plz sir tell me about this i really reqyire tihis
    commentReply   1 Reply
    ramreddy   636 days ago

    insufficient output
    sanjiv   964 days ago

    Ya its nice bt how & where to hide the sencer the IR transmitter & IR reviser on Basien ? If it hidden then it wil more effective by usear...Regards Sanjiv.
    mandeep   953 days ago

    What will be the cost
    manoj   849 days ago

    Where I can get the Solenoid valves?
    yokesh   844 days ago

    sir im working on this circuit i had tried but its not function so can i get any help?? just mail to me it will be very kind of you..
    bharathi   791 days ago

    can u give the connection circuit and videos of this urgently
    bharathi   791 days ago

    sir im working on this circuit i had tried but its not function so can i get any help?? just mail to me it will be very kind of you..
    NIKHIL RANJAN CHOUDHURY   675 days ago

    What type of solenoid valve will be required to make this project. Where from such solenoid will be available. Approx. cost of solenoid. Pl.give reply.
    Julius   626 days ago

    Is this working? Il planning to make it but I wanna make sure if this works. Please reply to my comment ASAP
    commentReply   1 Reply
    sayooj   524 days ago

    Its working.. bt difclt to hide the sensor...
    kiran   495 days ago

    Nice circuit cost of components is around RS 150 in india. Does anyone has pcb alyout. please post.
    vadi   485 days ago

    In India u cannot use 230v a.c for solenoid as all the wiring in most of the homes are leaky. You should use 12V d.c solenoid which more safe
    Ravi Gupta   430 days ago

    230 V solenoid is violation of safety rules. A better approach can be to use 6V or 12 V solenoid and same power supply can be used to generate 5V supply through 7805 for operation of other circuit.
    teja   419 days ago

    sir iam not getting transmitter output itselfplease send tranmitter&receiver circuits to my mail idas soon as possible please...........
    Col Consul   346 days ago

    Please suggest somebody who can repair my non functional sensor taps at Gurgaon.

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