Sound Activated LEDs can turn the LED ON or OFF when any of the sound signals are received by the circuit microphone. This is a basic Sensitive Sound Activated LED Flasher.
The circuit is very sensitive and can get sounds from numerous meters away. The electret microphone makes the circuit flash or blinks four LEDs when any stable sound signal receives. The affectability of the circuit can be balanced with the 1M variable resistor.
The circuit is fabricated by using a 2N4401 transistor. 2N4401 is a general-purpose NPN transistor subsequently it’s the emitter and collector will be reverse biased when the base pin is placed at the ground. And will be forward bias when its base pin receives the voltage signal. 2N4401 has increased esteem the value of 500; this value decides the intensification limit of the transistor.
Hardware Components
The following components are required to make Sound Activated LED Circuit
| S.no | Components | Value | Qty |
|---|---|---|---|
| 1. | Transistor | 2N4401 | 2 |
| 2. | Variable resistor | 1M | 1 |
| 3. | Resistor | 10K, 1M, 1K, 470R | 2, 1, 1, 4 |
| 4. | Capacitor | 1µF 50V | 1 |
| 5. | LEDs | – | 4 |
| 6. | Electret microphone | – | 1 |
| 7. | DC Supply | 5V – 12V | 1 |
2N4401 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N4401
Sound Activated LED Circuit
Working Explanation
The circuit is worked around two 2N4401 NPN transistors. The working voltage of the circuit is 5V to 12V DC. In the event that you are willing to work the circuit underneath 9V, at that point change every one of the 470 ohms LEDs current constraining resistors to 220 ohms.
The circuit is utilizing four 5mm LEDs. The number of LEDs can likewise expand whenever wanted. On the off chance that you need to build the LEDs, interface them the same as we have associates in the circuit. The most extreme number of LEDs ought not to be expanded from 25, in light of the fact that each LED will require 20mA and the transistor cannot deal with more than 500mA. On the off chance that you need to expand the number of LEDs up to 25, at that point utilize a higher yield transistor-like BD139 as Q2. A BD139 transistor can drive up to 50 LEDs with no problem at all.
Applications and Uses
- This Sound sensitive LED flasher is likewise valuable for hearing-impaired people. By using this circuit, doorbell or telephone ring sound creates light signs, and accordingly, hearing-weakened individuals can again play out this specific activity.
- This circuit can also be used as a sound indicator.
