A very simple touch free faucet circuit or touch free automatic tap circuit can be built using as little as an IC 555 and a few passive components, in order to implement a contact less water supply operation from the attached facet or the tap.
Drinking Water is Precious
纯饮用水which we normally get in our cities and homes is precious, and we are always advised to conserve drinking water as much as possible by saving unnecessarywastage of water由于粗心或疏忽。
Especially in public places this issue can become quite grim as many irresponsible citizens often forget to close a water tap or partially close it allowing unnecessary wastage of water.
An automatic tap system that would take care of the above condition could be a welcome change in many such places for ensuring the prevention of unnecessary throwing away of our precious drinking water into drainages.
Designing an Automatic Water Cut-off
We have already seen how theIC 555 can be used as an effective capacitive switch circuitwherein this device is able to sense a nearing human hand and activate its output accordingly. In the present concept we try the same concept to build the proposed touch free faucet circuit.
For higher accuracy and reliability you could also try implementing a specialized precision capacitive proximity sensor circuit for the same, although the installation procedures would remain the same.
下面的第一个电路显示了555 IC应用程序，可以尝试实现非接触式水龙头设计：
Circuit Diagram
image courtesy: elektor electronics
As can be seen in the figure above, theIC 555 is configured as an astable其引脚2用于感知人手的接近度或电容。
Pin#2 is terminated with a metallic plate (which could be replaced by the faucet body) such that whenever somebody approaches the tap for washing hands, the sensor is triggered activating the connected relay. The relay finally opens the tap valve for releasing water.
However in the above design the relay is supposed to remain activated only for a short duration of time, which means the individual might require to move his hand to and fro frequently if the washing is required to be for a relatively prolonged period.
下面显示的另一个设计可以执行相同的执行：
A Improved Faucet Control Schematic
image courtesy: elektor electronics
The above shown接近检测器电路is a transistor based design and is designed to sense a human hand when brought at a relatively close proximity to the indicated plate.
电路操作
The T1, and T2 transistors are rigged quite in the manner like a Darlington pairs forming a high gain detector stage.
与T1底座相连的电容板，由于差异而导致的微小电势差异板的电容为了响应人类的手并在其发射极的铅上传导一些电流，这是由T2挑选的，并在其收集器的铅中更大程度地放大。
This preamplified signal is detected by the FET stages, which further amplify it to a level strong enough to cause the relay to toggle.
Since the proposed touch free faucet design is an electrically activated device, the water control mechanism needs to be implemented through awater valve mechanism, such as a 12V solenoid valve system.
典型的12V电磁阀系统可以在下面见证：
Integrating a 12V Solenoid
这两个线索应该用switchable 12V supplyin order to close and open the water passage through the white plastic pipe. The white plastic pipe needs to be inserted in series with the faucet water transmission line so that the water supply from the faucet is appropriately controlled via the above discussed operations.
The basic connection details of the above mechanism in conjunction with the electronic circuit and the faucet can be seen below, the user can feel free customize the same in other ways as per his or her preference.
注意：如果水龙头身体对手部接近不反应，则可以用少量的额外金属板加固系统，以增加电容传感器and thereby ensure a reliable operation of the touch free faucet.
我可以连接PIR传感器电路,PIR吗faces towords the tap that sence hand only
WAS this suitabel . thank you
PIR can be used and with that you can use a simple transistor relay driver circuit, the above IC based circuit is not required
Minimum time adjustment of PIR sensor can be long for the faucet So much water consumption can be problem
Swagatam
I think the connections to the solenoid valve shown in the last picture is not correct.
Thank you Abu-Hafss, I have corrected it now…
Nived, You can combine the following concept with your PIR, that will work better:
//www.addme-blog.com/2012/05/simple-delay-timer-circuits-explain.html
或者简单地您可以修改现有的PIR电路，如以上延迟计时器文章中所述
sir
in case of my pir module..when we show our hand relay will open..it delays about 5s..is there any way to reduce the delay otherwise water will get wasted..if you want i can send picture of my pir..how to upload picture
NVD，如果延迟是从PIR模块本身发生的，则无法纠正，因为这意味着修改可能损害模块的内部SMD电路。
thank you sir for help
in circuit i saw capacitors like 470n 100n..what is that all.is it available in india..tell me substitutes for those components
i think i have to connect pin 2 to tap body..can you tell me the pin out for ic 2 lm311
NVD
470nF is equal to 0.47uF, and 100nF = 0.1uF you can try other value which are closer to this
首先，通过使用小板作为传感器确认工作表上的电路，如果其工作正常，则可以继续进行Tap Connection。
where. can i buy this capacitive touch plate..what is its cost in india..in online i saw some capacitive touch plate with 3 pin out.in your diagram there is only 1 pinout for plate..help me pls
the touch plate does not need to be purchased, it can be done by using any small suitable metal plate, or handmade by cutting a tin or aluminum with scissors.
thank you sir
I built the circuit on breadboard but it didn't work.Let me tell you what I did:
1. 8.and 9.resistors are 47K..right?
2.我使用了lm311 ..对吗？
3.我连接了其他零件。
As soon as I connect 12V to circuit the relay run/work.Relay musn't work normally, it must run when I approach the capasitive body termination.Where is the problem?
test the stages separately….initially keep the opamp stage isolated from the 555 stage by disconnecting it from R5/C5 junction….connect an LED in parallel to C3 and check its response when you bring your hand close to the capacitive plate, this will confirm the 555 working….after this you can proceed with the opamp stage separately
非常感谢
Dear Sir,
I used only 555 stage disconnecting second stage and connecting a led which is parallel to C3. However it didn't run as you said!?
Mustafa, the circuit was tested by the elektor electronics engineer, and this has taken from the same magazine, so it has to work.
also it was tested by Mr.Bugoy one of the dedicated readers of this blog, you can read the discussions below:
//www.addme-blog.com/2014/05/capacitive-switch-circuit-for-vehicle.html
但是，该电路仅在与电池一起使用时工作，但是与AC/DC电源一起使用时，该电路以某种方式无法正常工作
may be you can check it with a battery and see whether it responds or not….
Is there anybody who makes this circuit work/run?
好的..这可能是由DC ..您是正确的……再次感谢您的友善和兴趣
Are you able to show the making of an automated faucet via a video clip?
延迟时间，
Hello sir,
我正在自动洗手机上工作。因为我使用了红外传感器TX，Rx。目前，当传感器被感觉到泵一直持续到那时，它可以正常工作。现在，即使感应传感器，我也想在1-2秒后卸下泵。所以请给出解决方案。
Chintan，如果您使用晶体管作为输出放大器，则可以通过1N4148二极管将PIR输出连接到晶体管底座，然后在二极管和电路接地线的阴极上连接10UF/25V电容器。阴极将朝向晶体管底部，阳极向PIR销钉。
亲爱的斯瓦加塔姆先生，
Please provide us circuit for automatic faucet.
thanks & regards
亲爱的拉库马,我很抱歉我不能帮你的电脑B design due to work pressure! You may have to contact a professional online designer for this.
Can I have a diagram please
Good day Sir,
Are the circuits above sunproof?
I’m learning so much from your blog thanks alot
hank you Evangel, these circuits are capacitive based circuit so it cannot get affected by the sun light, so yes these are sun proof