Hobby Electronics

Simple Construction Projects

(These Circuit Diagrams are in PDF format.)

Flashing LED »
This simple project on stripboard makes a good low-cost project to check your soldering skills. The LED flashes at about 3Hz (3 flashes per second).

Adjustable Timer »
This circuit starts timing when switched on. A green LED lights to show that timing is in progress. When the time period is over the green LED turns off, a red LED turns on and a bleeper sounds. The time period is set by a variable resistor and it can be adjusted from 1 to 10 minutes (approximately). It could be used to set a time limit when playing games or as an egg-timer in the kitchen.

Heart-shaped Badge »
The badge consists of eight LEDs arranged in the shape of a heart. One LED is lit at a time and this 'chases' round the shape. It would be easy to adapt this project to create other shapes with the eight LEDs.

Simple Electronic Lock »
There are six (or more) push switches. To unlock you must press all the correct ones at the same time, but not press any of the cancel switches. Pressing just one cancel switch will prevent the circuit from unlocking. When the circuit unlocks it actually just turns on an LED for about one second, but it is intended to be adapted to turn on a relay which could be used to switch on another circuit.

Light-Sensitive Alarm »
The circuit detects a sudden shadow falling on a light-sensor and sounds a bleeper for a short time (adjustable). Normal lighting can be used, but the circuit will work best if a beam of light is arranged to fall on the light-sensor. Breaking this beam will then cause the bleeper to sound.

Christmas Tree Decoration Christmas Decoration »
18 LEDs flash at three different rates and you can use these to create a decoration of your choice. The circuit is kept simple (and cheap!) by using the 4060B chip which is a counter and oscillator (clock) in one package. The circuit requires a 9V supply, such as a PP3 battery.

Random Flasher for 8 LEDs »
This project uses a 4026 counter and display driver IC to flash eight LEDs in an apparently random manner. It can be used to create a display of your choice.