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Simple Gate Open/Close Controller Circuit

Simple Gate Open/Close Controller Circuit

The simple gate open and close controller circuit is designed to operate the gate through a couple of push buttons manually, it can be also modified for implementing the activation through a remote control.

How it Works

Referring to the shown, simple gate open, close controller circuit below, we can witness a rather straightforward configuration, essentially comprising of a transistor latch stage, a DPDT relay stage and a few push to ON/OFF switches.

The push switches S3/S4 play an important role in the circuit and ensure that the motor never gets overloaded when it reaches its end limits.

The images of the switches which are ideally suited to this application is shown just below the circuit diagram. These are quite popular and can be easily procured from any relevant electronic retailer.

Circuit Diagram

Simple Gate Open/Close set reset Controller Circuit

Set Reset Push Switches

Set Reset Push Switches


The above Switch is to be used for S3, S4

Transistor T1, T2 along with the associated parts form a reliable latch circuit, S1 and S2 are ordinary push-to-ON switches, where S1 is rigged as the "set" button, and S2 as the reset button, which work for opening and closing the connected respectively.

S3 and S4 are fixed across the end travel points of the gate mechanism, such that the gate pushes these OFF each time it reaches the end destinations, and releases while it moves away from the destination or while the gate is in the course of its travel.

Assuming the gate to be in the closed position initially, we can expect the following scenario:

Operational Steps

S3 in depressed position by the gate and therefore in the cut-off mode.

S4 in released position and therefore contacts closed and switched ON.

The latch circuit switched OFF, and so is the DPDT relay.

The DPDT relay contacts are at the N/C points.

With the above situation, pressing S1 initiates the following course of actions:

T1 and T2 instantly latches, actuating the DPDT relay in the N/O positions.

The motor now begins running through the supply via the S4 and the DPDT relay N/O contact supply in the set direction, enabling the gate to operate with an opening action. This also releases S3 in the process.

As soon as the gate reaches the end limit or the end destination, and opening up fully, it presses S4 cutting off the supply to the motor. The gate now halts and comes to a stand still.

How Motor Rotation is Flipped

This position can be maintained infinitely, until S2 is pressed, which breaks the T1/T2 latch, and deactivates the DPDT relay forcing its contacts to move across the N/C points.

This immediately flips the motor polarity causing the motor to rotate in the opposite direction and enables the gate to reverse back to its closing position. While in this mode the motor gets its power from S3, but only until it reaches its earlier destination, ie. in the closed position, when it presses S3, cutting off power to the motor and yet again disabling the motor.

The gate maintains this position until S1 is pressed yet again for initiating the opening action of the gate...thus the open/close operation of the gate is simply implemented by actuating S1 and S2 switches manually.

In order to execute a remote controlled open, close action of the gate, S1 and S2 could be replaced with momentary relay contacts, and the relays operated through the receiver unit of the remote control.

Any standard 400 MHz RF, 2-relay type remote control modules could be used for the stated remote open, close control of the gate.


About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!

24 thoughts on “Simple Gate Open/Close Controller Circuit”

  1. Good day sir
    i seriously need your help

    i want to build a circuit of an automatic gate open and close system where by one person can only go out at a time by clocking within a seconds of 3 and will be alerted if two people want to go our within that time…
    please i want to use it as my project in school…
    i will be much grateful if you can be of help
    Thank you

    • Hi Oliver, How do you want the gate to open, is it through a manual push button or an infra red sensor? Please specify I’ll try to help!

  2. I have an Apollo 1600 swing gate control card that is giving me problems. The swing arm tests totally proper and the 12v input to the card is correct. Originally believed the problem was in the NEC EN21N1NS relay. I replaced it with a new one. Now the motor does is only receiving a few volts and after the timer kicks in, the relay chatters. Tests show 12.5 volts arriving at the proper input to the relay. Both relay coils show proper resistance. I believe one or both of the relay coils are reacting to something causing their voltage to vary out of the norm. Any ideas where to hunt for the culprit?
    Thanks, Terry Owens

    • Assuming the power supply is OK, the problem could be in the card itself. Something may be malfunctioning in the card circuitry which could be difficult to diagnose without practically checking the card details. Putting a high value capacitor across the relay coil will stop the chattering but I don’t think that will solve the actual issue.

  3. Thanks Swag,

    If you can share your email ID , I will send you circuit diagram with modify for you to check and if necessary correct it.

  4. Hi All,

    Thanks for your explanation on topic.
    I would like to know how we can use this arrangement to use with remote controlling for open and close the gate.?
    could you please explain how or is possible?

        • Hi Shelton, the module which are referring to is 4 channel remote module, that’s why there are 4 outputs in them, but no problem you can ignore two of them and use only two, A and B for example.

          These pins can be connected to the base of two separate BC557 (PNP) BJT through 4.7K resistors, and 12V relays across their collectors and the ground line. The emitters will go to a 12V positive line. Make sure to connect 1N4007 diodes across the relay coils.

          The respective relay coils could then be used for toggling the gate ON OFF, by switching the set/reset points of the circuit through them.

  5. Hola buen día.
    Por favor, no use los simuladores artificiales, utilice su propio pensamiento o construir prácticamente, este circuito será definitivamente el trabajo…

  6. hola buenos días.
    yo hice el circuito en proteus 8.0 professional y no funciona no me invierte la marcha, y solo anda cuando S3 se encuentra cerrado.
    por que puede ser que ocurra esto? desde ya muchas gracias muy buenos aportes.

  7. freddie, how would you close it manually? because it is supposed to be operated with a motor, so manual pushing cannot be possible.

  8. Good day sir! Sir my problem for the automatic-sliding-gate-controller is automatically close, i need manual closing sir. And also the 10-15 min. delay off sir! willing to wait sir! Very glad that you reply to my message! Thanks you relly appreciate!

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