IC555 clap switch with timer mini project circuit

This is a special application of IC555 clap switch with timer mini project. It uses a condenser mic to pickup the clap like sharp sound and trigger the IC 555 designed as monostable multivibrator, as shown in the following circuit.

IC555 clap switch with timer mini project circuit
The practically tested circuit of IC555 clap switch with timer for your school or college submission as a mini project

Working of the circuit

The circuit uses one condenser mic to receive the clapping sound and IC 555 is used as one shot timer circuit. When power supply is connected to the circuit, pin-2 of IC 555 is held at +ve supply and so its output at pin-3 remains LOW and the LED D2 remains OFF.

When a sharp clapping sound is produced in front of the condenser mic MIC1, it gets quickly discharged into the base of transistor T1 (preferably BC549B, as tested in our lab), and T1 gets momentarily switched on. So pin-2 receives a short -ve pulse and IC 555 is triggered.

So the output at pin-3 becomes HIGH and the LED lights up. At the same instant, capacitor C1 starts charging through resistor R1. When voltage across the capacitor becomes equal or slightly greater than 2/3 of the battery voltage i.e. about 6V, the output of the IC becomes LOW and the LED turns OFF.

Capacitor C1 gets quickly discharged into pin-7 and the circuit becomes ready for the next clapping sound.

If again a clap sound is produced in front of the mic, same action is repeated.

The circuit is easy to construct even on a veroboard, but the lab tested actual size PCB layout of the circuit is given below.

If you have any difficulty in the circuit, during or after construction, you can contact our expert faculty. You can also refer our most popular article about the details of IC 555. To adjust the timing of one shot multivibrator of IC 555, you can refer to the online IC 555 calculator at this link. For more mini projects of IC 555 refer our special archive.

PCB Layout

IC555 clap switch with timer mini project PCB
Lab tested actual size PCB layout of IC555 clap switch with timer mini project

IC 555 soft touch switch door lock mini project

This is a very interesting IC 555 soft touch switch door lock mini project. It is very easy to construct and useful for your school or college level mini project submission.

The actual size PCB layout of the project is also given here, so that you will be able to construct it within an hour if you have all the components readily available with you.

IC 555 soft touch switch door lock mini project
The simple circuit of IC 555 soft touch switch door lock. Can be constructed within an hour as a mini project

Working

As shown in above circuit, the IC 555 is used as bistable multivibrator circuit. Its pin-2 i.e. trigger pin is held to +ve through resistor R1 and pin-6 i.e. threshold pin is returned to ground via resistor R2. Due to this connection, the IC does not get accidentally triggered or RESET.

The two miniature (soft touch) switches are used to control the door lock condition. Switch SW1 is a LOCK switch and SW2 is the UNLOCK switch.

A heavy duty solenoid SL1 is connected between pin-3 i.e. the output pin of the IC and ground through diode D1. Diode D2 is connected in antiparallel combination with the solenoid to absorb any back e.m.f. whenever the solenoid is deactivated. Thus diode D2 also protects IC 555.

One RED LED is connected in parallel with the solenoid through current limiting resistor R3 to serve as a LOCKed condition indicator – preferably it should be RED in color…!

Now when supply is connected to the circuit, the output of the IC remains LOW and the solenoid remains in UNLOCKed state.

When we press SW1 momentarily, the IC gets triggered through pin-2 as the trigger pin is momentarily grounded. So the IC is triggered and its output at pin-3 becomes HIGH. So the solenoid is activated and it locks the door. The RED LED glows indicating that the door is locked.

Now to unlock the door, press SW2. When SW2 is pressed momentarily, the output of the IC becomes LOW. The solenoid is now pulled back due to its spring action and the door is unlocked.

I recommend to use the battery supply or any full wave rectifier circuit having at least 9V supply. Also use the solenoid with less operating voltage. Here we have used 6V solenoid.

Note: The circuit is practically tested in Vidyasagar Academy laboratory and works very fine. If you notice that when the door is locked and if you switch on/off some other device like a tube light or fan, and the IC gets accidentally triggered or reset, then we recommend to use one small 0.01uF capacitor between pin-5 and ground. This will absorb any noise created in the circuit and will avoid accidental triggering or resetting. For any query, contact us.

PCB layout

This is the actual size PCB layout of the above given circuit.

PCB IC 555 soft touch switch door lock mini project
Actual size PCB layout of IC 555 soft touch switch door lock mini project

Video of circuit working

IC 555 infrared burglar alarm project

This is another circuit of IC 555 infrared burglar alarm project. It is very simple to construct and submit it as a mini project for your school and college level project submission.

The basic idea of the circuit is almost same used in the previous circuit of IC 555 simple burglar alarm, only the wire loop is replaced with LDR. You can also use infrared sensor in this circuit instead of LDR.

IC 555 Infrared Burglar Alarm circuit
Practically tested circuit of IC 555 Infrared Burglar Alarm as a mini project for school & college submission

Working of the circuit

As shown in the above circuit, the IC 555 is used as simple astable multivibrator circuit, but its RESET pin-4 is grounded through the LDR.

When power supply is connected to the circuit keeping the LDR fully lighted, pin-4 remains grounded through the LDR. So the IC gets disabled and its output pin-3 remains LOW.

But when the light on the LDR drops or the LDR becomes dark completely, pin-4 can no longer be held to ground level and it is now returned to +ve supply of the battery.

So the AMV starts oscillating at a rate decided by the combination of R1, R2 and timing capacitor C1. You can check the actual working of the circuit is following video.

PCB layout

The practically tested PCB layout of the above circuit is given below. The following image is actual size PCB layout. If you want to get the hardcopy of PCB layout of this circuit for actual construction, then contact us. We shall send you the actual size PCB layout for free.

IC 555 Infrared Burglar Alarm PCB
Actual size PCB layout of IC 555 Infrared Burglar Alarm

Video of circuit working

For complete details of IC555, refer to our most popular article on IC555.

IC 555 simple burglar alarm mini project

This is another circuit of IC 555 simple burglar alarm mini project. It has been fully tested in our lab and its PCB layout is also given below.

The circuit uses the simple trick that whenever, pin-4 i.e. the RESET pin of IC 555 is grounded, all its functions stop. But when it is raised to +ve supply, then the IC works normally.

IC 555 Simple Burglar Alarm Circuit
Practically tested circuit of IC 555 Simple Burglar Alarm

Working

The circuit is basically used as Astable multivibrator circuit. But since pin-4 of the IC is grounded it remains in dead conditions till the burglar loop is broken.

As shown in the above circuit diagram, when power supply is connected to the circuit, it remains silent. This is because the pin-4 i.e. the RESET pin of the IC is grounded through the burglar loop, shown on the left side of the circuit.

Now when the loop is broken by the burglar, pin-4 is raised to +ve supply through resistor R3. So the circuit starts working as astable multivibrator and the output of the IC becomes HIGH and LOW periodically.

The buzzer connected across the output and ground start producing whistle like sound. You can check the actual working of the circuit, in following video.

Note: The value of R3 we have used is just 10k ohms but you can increase it upto 100k ohms if you are having the problem of battery drain while monitoring the burglar activity.

PCB layout

IC 555 Simple Burglar Alarm PCB
The practically tested (not actual size) PCB layout of the project

Video of circuit working

ic555To understand the working using animation, you can download the Circuit Wizard file of this project. You can run this circuit to actually see the voltage levels, current direction, etc. For complete details of IC555, refer to our most popular article on IC555.