Morning/Sunrise alarm generates beep sounds and LED flashes according to the sunlight. The most fascinating aspect of this circuit is that the speed of the beeping signal and the blinking LED will slowly rise as the sun rises. The circuit generates beeps and LED flashes in a few seconds distances when LDR in the circuit absorbs low light. But the number of beeps and flashes can rise gradually as the sunlight on the LDR surface rises.
LDR ( Light Dependent Resistor ) is also known as a photoresistor, photocell, and photoconductor. This is one form of resistance, the resistance of which changes based on how much light falls on its surface. When LDR is in darkness, it may be used to switch a light on or switch a light off while it is in light.
Hardware Components
The following components are required to make Morning Alarm Circuit
| S.no | Components | Value | Qty |
|---|---|---|---|
| 1. | LDR | – | 1 |
| 2. | Resistors | 1K, 470 ohms | 1,1 |
| 3. | Capacitor | 100uF | 1 |
| 4. | IC | NE555 Timer | 1 |
| 5. | LED | – | 1 |
| 6. | Power Supply | 9V to 12V | 1 |
| 7. | Piezo buzzer | – | 1 |
| 8. | Potentiometer | 1K | 1 |
NE555 IC Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 555 Timer
Morning Alarm Circuit
Working Explanation
The circuit can run 9 volts to 12 volts DC. You can even use 6 volts to control the circuit. The value of the current limiting LED resistor falls from 470 ohms to 150 ohms for running the circuit with 6 volts. The buzzer volume is operated with a 1K variable resistor near the piezo buzzer. A piezo buzzer is a form of the electronic system used to produce a signal alarm or tone. The is designed around the famous timer IC NE555. The 555 can be used as an oscillator and as a flip flop element to have time delays.
Applications and Uses
This circuit is used in alarm clocks.
