How to build Fading Red Eyes

Two Light Emitting Diodes slowly light up and fade away due to the circuitry, giving it a feel of blinking red eyes in darkness.
It is the perfect way to set up your own horror show in Halloween. It can also be installed in series for the Christmas tree or during Diwali or a decorative power indicator for the daily appliance.

A 3 volt linear wave is generated at Pin 1 via LM 1458 IC and followed by a transistor which buffers the emission. A 47 K resistance coupled with a 22uF capacitor is joined at Pin2 to limit the frequency to 0.5Hz. The rate can be varied using a 100K pot(potentiometer) replacing the 47K resistor.

Two operational amplifiers govern the circuit. The transitional voltage is produced by the first op-amp which slowly modulates voltage between 3 to 6 volts. The second op-amp supplies alternating voltage of 2 and 7 volts to charge the capacitor and discharge it via constant current.

Two 47K resistors establish a fixed voltage when joined across Pin 3 & 6 to keep the reference voltage constant. One op-amp works as an inverted amplifier connecting a capacitor across Output Pin 1 and Pin 2 which inverts the output. One of the op-amp compares the voltage to regulate the output in Pin 7. The reference voltage needs to be lower than the input at one point and needs to be higher with the reference at the higher end. A 100K resistance provides a positive feedback and controls the switching point via a capacitor that changes the direction of current. The op-amp also changes its directional output. The triangular waveform at Pin 1 is achieved which moves up or down keeping input constant at 4.5 Volts.

The Point when the LEDs go off can be adjusted by altering the resistance value across Pin 3 and grounding Pin 6. Using a 9 Volt Battery will ensure long operational hours.

Please note that LEDs have a narrow viewing angle of 30 degrees and appears brightest if viewed directly from the front or it might loose the desired effect of the eerie feeling it can generate.

Circuit diagram

The circuit here shows a double pair of LEDs that operate intermittently such that while a pair illuminates, the other pair fades out.

Comments

Build a 3000W Stereo Power Amplifier Circuit Diagram

How to Build a 3000W Stereo Power Amplifier Circuit Diagram? Lets start first we define 3000wstereo power amplifier circuit diagram this circuit has a power output of up to 1500W RMS power amplifier circuit is often used to power sound systems spelunker for outdor. In the final image can be seen a series of power amplifiers using 10 sets of power transistors for the ending. This power amplifier circuit using a transistor amplifier from the front, signal splitter, driver and power amplifier. Current consumption required is quite large power amplifier that is 15-20 A 1500W power amplifier circuits for this. Supply voltage needed by the power of this amplifier is the optimal working order symmetrical 130VDC (130VDC-130VDC ground). 1500W amplifier circuit below is a picture series of mono, stereo if you want to make it necessary to make two copies of the circuit. For more details can be viewed directly image the following 1500W power amplifier circuit. The series of High Power Amplifier 15...

Build a Key Operated Gate Locking System Circuit

This simple key-operated gate locking system allows only those persons who know the preset code to open the gate. The code is to be entered from the keypad within the preset time to operate the motor fitted in the gate. If anyone trying to open the gate presses a wrong key in the keypad, the system is disabled and, at the same time, sounds an alarm to alert you of an unauthorized entry. Figs 1 and 2 show the block and circuit diagrams of the key-operated code locking system, respectively. Connect points A, B, C, D, E, F and ground of the circuit to the respective points of the keypad. Keys S7, S16, S14 and S3 are used here for code entry, and the remaining keys are used for disabling the system. It is very important to press the keys in that order to form the code. To start the motor of the gate, press switches S7, S16, S14 and S3 sequentially. If the keys are pressed in a different order from the preset order, the system will lock automatically and the motor will not start. Fig. 1: Bl...

3 Channels Audio Splitter Amplifier Circuit Diagram using TL084

This is the schematic diagram of 3 channels audio splitter amplifier circuit which built using op-amp IC TL084. The 3 channels amplifier output distribution applies a single TL084. 3 Channels Audio Splitter Amplifier Circuit Diagram The very first step is to capacitive coupling having a p. 1.0 ~ electrolytic capacitor. The entries are railways Vee Y2 or 4.5 V. This enables working with an individual 9V power source. A voltage gain of 10 (1 M?/100 Kohm) is obtained in the first stage, as well as the other three floors are connected as a unity gain voltage followers. Every single output stage drives independently through an amplifier output 50 pF capacitor towards the resistance of 5.1 k ohm load. The response range is flat from 10 Hz to 30 kHz.

TREE

Search This Blog