Automotive Circuit Diagrams

Curtain Opener and Closer Circuit

Simply by flipping a switch this circuit will opener and closer the curtains at your house and business. As a result of this one-of-a-kind circuit, we don’t have to move from one location to another to open and close the curtain. This circuit is utilised in the home, especially for tiny doors and windows. It can be easily fastened with a curtain because to its tiny size and readily available components. With the help of an adapter available on the market, you may also deliver power to the circuit.


  • Curtain Opener and Closer Circuit Diagram:
    • Description:
    • How D Type Flip Flop Works:

Curtain Opener and Closer Circuit Diagram:

Opener and Closer Circuit

Components used in this Circuit:

  • IC
  • IC1 (CD4013)
  • IC2 (ULN2003)
  • Resistor
  • R1-R4 (5.6k)
  • R6, R5 (1K)
  • C1 (. 1uf)
  • Stepper Motor


This circuit comprises two integrated circuits known as CD4013 and ULN2003, along with a few other readily accessible components.

The CD4013 IC incorporates two independent D-type flip-flops on a single chip, each capable of existing in one of two states, either 0 or 1, and retaining information. Each of these modules features a set of pins designated for functions such as data, set, reset, clock input, as well as a pair of complementary outputs, denoted as Q and.

How D Type Flip Flop Works:

The D input, commonly referred to as the data input, serves as the sole input for a D-type flip-flop. Below is the truth table for a D-type flip-flop:

In this context, the input data becomes visible at the output following the clock pulse’s completion. Consequently, there is a delay in the flow of data from input to output, characterizing it as a delay (D) flip-flop. This characteristic makes it suitable for storing single-bit binary data as a delay device or latch. The clock input line (CK) within this circuit governs the flip-flop’s operation, determining whether the input data is acknowledged or disregarded. Typically, the input takes the form of a clock signal. If the clock input is at a binary high state (logic 1), the data on the D line is stored in the flip-flop.

While the clock line remains high, the regular output will simply mirror or replicate the D input. When the CK line is low (binary 0), the D input line is recognized, preserving the bit stored in the flip-flop from a previous state. The behavior of the D line can vary, but it will be ignored if CK is low.

The CD 4013 chip is available in a 14-pin dual inline package. To grasp the operation of the circuit diagram, it’s advisable to first familiarize yourself with its pin layout.

CD 4013 Pin DiagramCD 4013 Pin Diagram – Electronics Hub

  1. Pins 1, 2, 13, and 12 are known as complementary outputs, therefore they are both displayed as outputs, but in reverse order. If Q is 1 on the initial flip flop, then Q Bar will be 0. The same can be said for another pair of flip flops.
  2. Pins 5 and 9 are known as Data pins, and they are normally connected to one of the outputs, which can be Q or enlargingnction of enlargement the appsquare wavesclock for square wave and other waves, respectively. They can also be terminated to any other logic level, which means they can be connected to the circuit’s supply line or ground. We’ve combined the Q Bar and Data Pin 5 in our circuit.
  3. Clock input is defined as pins 3 and 11. It receives the input signal for the D type flip flop to work. You can give signals using a transistor setup as an astable multivibrator, or you can use a logic gate such as a NANA gate or a NOR gate. With the help of a transistor, we provide the clock input in our circuit.
  4. Pins 4, 6, 10, and 8 are known as the set and reset pins, and we will receive the output if any of these pins goes high. These pins are generally grounded with a high value resistor and assigned to a logic level for protection. After that, the input can be programmed to alternately react to positive peak pulses in order to regulate the logic stage of the computer.

The pins responsible for supply and ground connections are situated at positions 14 and 7, respectively. Pin 14 serves as the Vcc power supply input, with the important caveat that the voltage supplied should not exceed 15V, as exceeding this limit can result in damage to the IC. On the other hand, pin 7 functions as the ground connection, and it should be securely connected to the IC’s negative supply input.

The ULN2003 IC can be described as a high-voltage, high-current Darlington array. Each ULN2003 IC comprises seven individual Darlington transistor pairs with open collector outputs and a common emitter. Additionally, the ULN2003 can be effectively employed to drive a stepper motor and is commonly utilized in a diverse range of applications, often in conjunction with relay drivers.

The ULN2003 is compatible with 5V TTL and CMOS logic devices. Each channel or Darlington pair within the ULN2003 IC is rated to handle currents of up to 500mA, with the ability to withstand peak currents of up to 600mA. Below, you can find the pin diagram for the ULN2003 IC:

ULN2003 Pin DiagramULN2003 Pin Diagram

Understanding the operation of this circuit is quite straightforward. Ensure that the circuit is assembled correctly and verify all connections.

In this setup, both flip-flops are utilized. To open the curtain, simply press switch S1 for a brief moment. Since one end of the switch is connected to the power supply, it will supply voltage to pin 6 of IC1 (the set pin). When pin 6 goes high, it triggers the highest output at pin 1 of IC1 (the Q output). Consequently, pin 2 of IC2 goes high, causing the geared motor connected to its output to start rotating in the opposite direction, thus opening the curtain. When the curtain is fully open or if you wish to halt the motor midway, press switch S2, which is connected to pin 4 of IC1 (the reset pin). This action deactivates or stops the stepper motor.

A similar scenario applies when you want to close the curtain. Simply press switch S3, which is connected to pin 8 of IC1 (also a set pin). This causes the geared motor to run in the anticlockwise direction, closing the curtain. If you wish to stop the curtain from closing or pause it in an intermediate position, press switch S4 to turn off the stepper motor. This setup allows you to effortlessly open and close your curtain from a single location without the need to physically move, just by pressing the appropriate switch.


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