Hobby Electronics Circuits and Projects

john November 12, 2011 6 Comments

For all electronic hobbyists out there, CircuitsToday is listing some of our own hobby electronic circuits for you. Most of these circuits have been tested by us. You can bring in your own modifications to the circuit. For beginners, these electronic hobby projects may be a little difficult. You can feel free to comment below and ask whatever you want to know. We will help you with whatever information we can provide. Click on the link of each heading given in the list below, to go to the main content. Do not forget to check out the comments as well, to get a better idea of the electronic hobby circuits.

1.       Dark Detector Circuit

This hobby circuit is used to produce an alarm as soon as the light inside a room goes off. The main components used are a basic 555 timer IC and Light Dependent Resistor (LDR), and an output buzzer alarm. The output of the sensor is given to the NE 555 IC. When there is proper light inside a room, the resistance of the sensor will be very low. As soon as the light goes off, the resistance begins to increase. This in turn triggers the IC which is connected to the alarm, and thus produces an output sound. This type of hobby projects can be easily modified to switch other electrical components by using a relay and a transistor to be connected to the output of the 555 timer instead of the buzzer alarm.

2.       Musical Car Reverse Horn Circuit

This interesting circuit is used to make a musical horn as soon as you put your car in reverse gear. This type of hobby electronics projects works with the help of two integrated circuits. One is a simple 7805 voltage regulator IC that is used to minimize the car battery voltage to 5 volts. A further drop to 3.6 Volts is needed and this is given by two diodes. This voltage is given to the second IC, called the UM66. This IC is known to be a music generator. When the car is put in reverse gear, the switch becomes on and the circuit gets connected to the car battery. This causes the UM 66 to produce a music tone. This tone can be further amplified by connecting a transistor driver from the output of the IC to the loudspeaker. The hobby circuit diagram can be seen in the main post given above.

3.       Dancing Light

The hobby circuit diagram of the circuit is given in the original post. This circuit uses an astable multivibrator using a 555 timer IC. The clock pulses from the timer are given to an IC called CD4017. The output of the IC becomes high alternatively. Thus, the LED’s also turn on alternatively, giving it a dancing feel. You can customize the speed of the LED glow by changing the frequency of the clock pulses generated by the timer IC.

4.      Jet Engine Sound Generator

Hobby circuits such as these can be made with the help of the sound generator IC HT2844P. The IC is designed to produce four different sounds of a jet engine like the missile sound, machine gun sound, high speed sound and low speed sound. Each sound is assigned its respective IC number. You just have to connect the associated pins to the ground by using the respective push button switches. You can also connect an LED to the circuit as an indicator to show that the sound has been activated. The hobby schematics can be obtained from the original post given in the link above.

5.       Whistle to Beep Circuit

The circuit consists of a CMOS Hex inverter IC which helps in producing a small beeping sound, whenever you make a whistle. The beeping sound will last for about 3 seconds. There are altogether 6 inverters in the IC. One of them is connected to an audio amplifier that amplifies the signal packed by the microphone. Another inverter of the IC is connected as a Band Pass Filter (BPF) with a center frequency of about 2 kilohertz. The circuit also contains an astable multivibrator and a monostable multivibrator apart from the buzzer output. Check out the hobby circuit diagram show in the link above.

6.       Puff to OFF LED Circuit

A condenser mic is used as a sensor to sense a puff made by the user and thus make an LED switched OFF. Two transistors are connected as a latching pair, which drives the LED to glow. The LED remains ON as long as the puff is given to the mic. The mic converts the sound pressure into an electrical signal and is amplified by a transistor. The output of the transistor drives the LED to the OFF state. A switch must also be given to turn the LED back t its glowing position.

7.       Touch Switch Circuit Diagram Using NE 555 IC

The circuit consists of a small touch plate controller using the 555 timer IC. Hobbyists can easily design this circuit for various applications like doorbells, buzzers, toys, and so on. The circuit mainly consists of a relay that operated for a preset time and then turns off immediately as soon as anything touches the touch plate. A transistor is also used to drive the relay, which can be used to drive loads like bell, lights or motor.

8.       Automobile Turn Signal Circuit

Electronics enthusiasts may find this circuit very interesting. The main objective of the circuit is to provide sequential signal light in automobiles. Two main IC’s are used in this circuit – a TS 555 CN CMOS timer IC and a CD4017 decade counter IC. The CMOS IC is connected as an astable multivibrator so as to trigger the other one. When the CD4017 IC is triggered, the output will go high and low in sequence and the speed of the sequencing will be proportional to the triggering frequency. Four transistors are also provided to drive the corresponding Light Emitting Diodes (LED). Check out the comments on the post as well to know more about the modifications that can be brought to the circuit.

9.       Parking Sensor Circuit

This circuit can be practised on your car for sensing the distance between the rear bumper of the car and any obstacle behind the car. The distance can be understood from the combination of the LEDs used in the circuit.  The 555 timer is used as an astable multivibrator in the circuit. This timer drives the infrared diode that is connected in the circuit to emit infrared pulses. The operating frequency of the transmitter is around 120 Hertz. Take a look at the circuit diagram to know more about it. A detailed explanation is also given in the post above.

10.     Electronic Toss Circuit

A timer IC is used as an astable multivibrator here at a frequency of 10 hertz, along with a 74LS76 dual JK flip flop. The main objective of the circuit is to toss head or tail. The output of the timer is inverted using a transistor. The component details and the explanation is given in the post above.

  • clerfin
    May 22, 2014

    i want to make clap switch
    how is it

  • anish jose
    November 6, 2013


  • abdul
    August 3, 2013

    B’cos i like an electronics

  • February 7, 2013


  • Albus
    November 15, 2011

    you need the voltage doubler ckt…..

  • vandana
    November 12, 2011

    i want club two voltage source……….. how can do it..?

    suppose two Ac voltage given to i/p…. i want the sum of these in o/p..

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