- 1 Introduction
- 2 Basics of thermistor
Today’s our post on “How to make electronic fire alarm at home”. we tend to recently produce a project on “electronic fire alarm”. you’ll be able to realize video tutorial of this project on YouTube. This project is extremely easy and simple to form. once fire alarm circuit done then this device can sense the fire and buzzer sounds alarm.
This project contain this main components Power offer, Operational electronic equipment, Sensor. This circuit power by 9 volt powered. Operational electronic equipment amplify the signal and buzzer provide the alarm and thermister sense the heat/fire.
Fire Alarm Circuits and Smoke Sensors ar a region of the protection systems that facilitate in detective work or preventing harm. putting in hearth Alarm Systems and Smoke Sensors in business buildings like offices, moving picture theatres, looking malls and different public places is mandatory.
Basics of thermistor
In this project we uses 10K thermistor is associate electrical device that depends on the temperature. Resistors are wide used as associate current clipper. This may additionally utilized in temperature controller device.
Mainly 2 forms of thermistors are utilized in the industries.
NTC kind thermistor it’s resistance decreasing with increasing the temperature.
PTC kind thermistor it’s resistance increasing with increasing the temperature.
List of Parts
- 10K thermister – 1 No.
- 4.7K resistor – 1 No.
- 10K POT – 1 No.
- LM 358 – 1 No.
- 8 pin IC socket – 1 No.
- 5 Volt Buzzer – 1 No.
- Vero Board -1 No.
- Hook up wires
- LM7805 – 1 No. (Optional)
- 10 uF 25 Volt Capacitor – 1 No. (Optional)
- 10 uF 10 Volt Capacitor – 1 No. (Optional)
- 9 Volt battery 1 No.
- Battery clip – 1 No.
List of Tools
- Soldering iron
- Screwdriver set
- Hacksaw blade
- Wire stripper and Cutter
- Helping hand
Circuit Diagram/ Schematic Diagram
LM7805 Voltage Regulator
Circuit Diagram/Schematic Diagram
As per circuit diagram please design your PCB soldering design. Cut PCB as per your design using as shown in video. Draw the component and layout on PCB. Basically this circuit operates on 5 Volt, but in this video we are showing that we are use 9 volt battery. You can also run project on 5 volt power supply. While you are using 9 volt power supply use LM7805 voltage regulator as optional but you can use 9 volt power supply directly. for more details please visit our YouTube channel.
1. Cut Vero Board
We are using vero board in this project for custom PCB building. You can use any other type as you need or any other custom type. After cutting PCB we made an track on PCB as shown in video. Also mark for positive and negative terminal on the PCB.
2. Power Supply
This circuit is run on 5 volt DC power supply. You can also use an 9 volt power supply. In this tutorial we are using a 9 volt power supply. If you are using a 5 volt power supply then you have to use an 7805 voltage regulator. Schematic diagram shown above image.
3. Mount the 555 IC
We are using 555 timer IC in this project. To mount 555 IC we are using 8 pin IC socket for protection of IC form the heat. 555 IC will be mount in the center portion of circuit. Solder pin no.8 of 555 IC with positive track and pin no. 4 to the negative track.
4. Mounting 10K POT
In this project 10K POT used to set the sensitivity of the circuit. This pot has a three lag connection both end legs are fixed resistor and center pot is working as a variable pot. Solder both end of the POT between positive and negative terminal. Variable point of POT will be solder with pin no. 2 of 555 IC.
Make series connection of the 10K thermister and 4.7K resistor on PCB. Connect both end of series connection with positive and negative track. The centre terminal of the resistor and thermister with pin no. 3 of 555 IC.
Positive terminal of buzzer will be connected with pin no. 1 of 555 IC. Negative terminal of buzzer will be connected with negative track.
Testing and POT setting
We are replacing 10K POT with good quality POT as shown in video. The main function of port is to set sensitivity of circuit. First connect battery to the circuit and then set pot by using screw driver. During adjustment of POT at any one point the buzzer will be sounds that will be our set point. We have to slightly lower the POT value at which point buzzer sounds. Now as shown in video using lighter touch flame to the thermister and buzzer will sound.
Now our circuit is ready to use. In place of 5 volt buzzer you can also place a relay and On/Off multiple devices and alarms.
We hope you enjoyed this project, If you have any query on this tutorial comment in below section or you can contact us.
For more interesting video tutorials please visit our you tube channel : Weekend Fun