Automatic Water Tap Using 555 Timer

This project is sensor based automatic water tap. The tap starts whenever anyone put his/her hand in front of sensor which is below the water tap.

The Ir sensor is made using 555 timer, used as astable multivibrator, vibrating at around 38 KHz. and another 555 timer ic is used as monostable multivibrator for tap circuit.

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Step 1: Parts Needed

For Sensor Circuit
  • lm555 timer ic
  • 103pf ceramic capacitor
  • 18k resistor
  • 1k resistor
  • 22R resistor
  • 102pf ceramic capacitor
  • IR led
  • 4.7uf electrolytic capacitor
  • 10k resistor
  • 100R resistor
  • TSOP1738 IR receiver
  • red leds

For Main Circuit

  • 12-0-12 step down transfarmer
  • 1N4007 diode
  • LM7805
  • 1000uf electrolytic capacitor
  • BT136 triac
  • LM555 time ic
  • red leds
  • 1k resistor
  • 10k resistor
  • 103pf ceramic capacitor
  • 100k resistor
  • 100R resistor
  • BC547 transistor
  • Solenoid Valve (you can get one from old automatic washing machine)
  • Dotted PCB

Optional Parts

  • Wash Basin
  • wash basin stand
  • plyboard
  • Colors

Step 2: Circuit Diagrams

Here are both of the circuit diagrams for IR sensor and master circuit. I have also included eagle schematic files.Make both the circuits on different PCBs.

The Sensor Circuit

The sensor circuit is based on the 555 timer ic in astable mode. 555 timer ic vibrates at 38KHz and that waves are transmitted using IR led and if any obstacle is in front of IR led the rays reflects and the TSOP1738 IR receiver modules recieves and sends signal.

The Main Circuit

In main circuit 555 timer ic is used in monostable mode hence when it receives any signal from IR sensor then automatically enables the solenoid valve for some time and then automatically turn off the output current in BT136 Triac.

Step 3: Assembling

You may assemble the things like as shown in images or use your own way.

Step 4: Final Touch

I have Used Colors and some lightening connections to make it more attractive.

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    9 Discussions


    1 year ago

    how can adjust off time even obstacle is in front of IR led?


    2 years ago

    give me pic of circuit made in breabroad


    2 years ago

    i just want to check output without ant tap or besin n water . what should i do?

    i made this one without solenoid valve n triac


    3 years ago


    Nice project!

    As you are using mains to control the solenoid, it would be a good idea to use a residual current circuit breaker (see wiki or Google.) to give some protection in case of any faults and also to make sure any copper or other metal piping is properly earthed.

    I'm not an electrician but I think a quick glance at the 17th (I think ) edition of the wiring regulations (if a UK user) would also be worthwhile, especially if you want to install this indoors in a bathroom or kitchen!

    (Personally I think that the typical solenoid would give enough isolation. Usual disclaimers about suing me!)

    I don't want to be a wet blanket about this project but Health and Safety will have their little way if anything goes wrong.

    9/10 for usefullness!

    Muhammad Umar Nazir

    3 years ago

    Dear Jaspal,

    Your project is very good.

    I want to modify it little bit. I just want to modify it function and want to add instant water geyser with a mini storage tank. Because you must have mini/small tank, otherwise instant water geyser will off & on as solenoid valve gets off& on. Hence geyser could not heat-up properly. Instant heater must require 5-6 seconds in on state to output warm water.

    I have full sketch in mind about how and where things are attach to achieve the required results,but I am lacking electronics knowledge. Which actually control the circuit.

    Please help me to make that.

    Any one interested, please contact me on

    2 replies
    Bhuva28Muhammad Umar Nazir

    Reply 3 years ago

    Hi Umar ,

    Your thought is great , But i have seen a already build product of the same in my friends home. I think its bajaj company product , apologies if its name is incorrect. Just check out..Sorry for the bad news but still you can take it a challenge to improvise the product..


    Reply 3 years ago


    Could you please send me the link of the bajaj company product?


    Definitely a good "smart" water conservation- waste reduction device, nice work!