Versatile Audio-Visual Alarm

 

Versatile Audio-Visual Alarm

Requirement 

• Produce audio-visual effects as per your requirement 
• Sound produced by these circuits may not be always pleasant to hear

NE555 TIMER 

• The 555 timer IC is an integrated circuit used in a variety of timer, delay, pulse generation, and oscillator applications. 

1. Ground 

2. Trigger 

3. Output 

4. Reset 

5. Control Voltage 

6. Thresold 

7. Discharge

8. Vcc

• Piezo Buzzer 

Piezo buzzers are simple devices that can generate basic beeps and tones. They work by using a piezo crystal, a special material that changes shape when voltage is applied to it. Like a tiny speaker cone, it can generate a pressure wave which the human ear picks up as sound.

• Resistors R1 and R2 and capacitor C1 determine the frequency of the LED’s blinking 

• The frequency is selected usually within the range of 0.1Hz to 20Hz 

• It is suggested to keep the total output current drawn from NE555 below 100mA.

• Group1 is built around resistors R4 and R6 along with LED1 through LED6. 

• Group2 is built around resistors R7 and R8 along with LED7 through LED12. 

• Difference between the Group1 and Group2 is the use of resistor R5 and capacitor C2. These two components give light-decay effect to the LED’s and a pleasant low-pitch sound to piezo buzzer in Group2 
• Resistors R4, R6, R7 and R8 are selected according to the number and type of the LED’s used. If the values of these resistors are too low, the output of the timer will be overloaded and the LED’s in the upper and the lower branches will get activated simultaneously. 

Simulation in tinkercade

For 1st Few Time Green LED’S Are ON

For Remaining Time Red LED’s Are ON

So Basically By Changing The Value Of Resistors And Capacitors We can Get Different Type Of Sound 

credit goes to Dhruvin Rajpura