Egg Timer

Posted on Feb 6, 2014

This egg timer, which is both simple and functional, shows once again that it is not essential to use a microcontroller for everything these days. The circuit consists of only two ICs from the standard 4000 logic family, a multi-position rotary switch and a few individual components. The combination of a 4040 oscillator/counter and a 4017 decimal

Click here to download the full size of the above Circuit.

counter is certainly not new, but it is an ideal combination for timers that are required to generate long intervals that can be programmed in steps. The circuit can be directly powered from a 9-V battery, without using a voltage regulator. The signalling device is a 12-V buzzer, which generally works quite well even at a much lower voltage. We won`t explain the operation of the two ICs here; if you would like to know more about this, we recommend consulting the device data sheets. The RC configuration has been selected for the oscillator circuit of the 4060, since the frequencies of standard crystals and resonators would be too high (even 32. 768 Hz is much too high), making it impossible to achieve the desired times. With an RC oscillator, it`s also easier to modify the times to suit our purposes. For instance, if the oscillator frequency is reduced by a factor of two, we obtain a range of 1 to 16 minutes in steps of 1 minute. The range is split into two by taking advantage of the fact that the 4017 has an AND gate at its input (with an inverted input). The two ranges overlap by two steps. The oscillator has been dimensioned such that the 23 divider output (pin 14) has a period of 30 seconds, so IC2 receives a clock pulse every 30 seconds. This means that the oscillator frequency must be set to 8. 5333 Hz. The first output of IC2 is active after a reset, so it cannot be used. If S1 is in position I, pin 14 of IC2 is...

Leave Comment

characters left:

Related Circuits

Ultrasonic sound producer(insect repellent)

As we know many kinds of insects have their tendency to hear ultrasonic sound(which cause them irritation), this project is very useful to swept away those insects like mosquito cockroach etc.

PIC 18 Explorer Board LCD Example Code With SPI Library

Learn to use the LCD display on your pic 18 explorer board with the spi library. The spi library will be used to easily display characters on the LCD. You will also learn how io expanders work.

cellphone operated land rover

I know the general rule of world that reading makes man ready, writing makes man everyday but practice makes man perfect. Only theoretical knowledge is not enough for an E. C (Electronics and...

RC5 Protocol Decoding with 8051

Infrared light is electromagnetic radiation with longer wavelengths than those of visible light. Infrared light is used in industrial, scientific, and medical applications. Most of the remote...

Digital Clock Using Microcontroller 89C52/89S52

Are you a beginner in micro controller projects and are you stuck where to start from if yes, then this is one of the simplest mini projects that you can start from. This mini project will give you...

Password(code) Based Digital Locking System Using Microcontroller 89C52/89S52

entering of the password, the application as in this case "led" will glow. In this Digital locking system project you will learn more about interfacing keypad and 16x2 LCD to your micro controller...

Shifter(Bit Shifter) in Computers and its

EL Lamp Driver Using HV832MG

An EL lamp is a solid state, low power, uniform area light source. Because of its thin pro ¬le (as thin as 0. 3 mm) and the fact that it can be built into almost any size and shape, EL lamps are...

New Circuits

Zero consumption Anti-theft High power Code Switch for E-Bike Batteries

This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
Ultrasonic distance finder circuit

The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Simple Metal detector circuit with CD4030

Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Fully automatic watering circuit for flower pots

Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
Simple deep searching metal detector circuit

The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
Sub-Harmonic Bass Converter for Electric Guitars

The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
Echo Depth Sounding Sonar for Boats

In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
100W HiFi Audio Amplifier Circuit

This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
Plant-Pot Water Level Indicator Circuit

A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....