Circuit of fire alarm detection

The rooms are vulnerable to fire as a storage material, flammable, requires a system to prevent the occurrence of a fire. For example, using a fire alarm detection, so for example occur if a flame that can quickly and others that are easily fire did not cause a fire is greater.

Here is a simple alarm circuit is based on the LDR and the lamp of a pair of smoke alarm sensors fire.The sensor works produced fire.The circuit produces an alarm when a fire smoke.

 

Fire alarm detector Components :

• The speaker can be 8Ω tweeter.

• POT R4 can be used to adjust the sensitivity of the alarm.

• POT R3 can be used to vary the volume of the alarm.

• Any general purpose NPN transistor (BC548, BC148, 2N222) can be used for Q1.

• The circuit can be powered by a 9V battery or 9V DC power supply.

• On the contrary, it is bright LED bulb 1K resistor in series on it.

Where there is smoke from the bulb will drop directly LDR.The LDR resistance is low and hence the voltage across its terminals (less than 0.6 V). The transistor is blocked and no happens.When there is enough smoke to obscure the light falls on the LDR, LDR resistance increases and the fact that the voltage across the transistor passes it.Now ON.This feeds IC1 and the output 5V.This power tone generator IC UM66 (IC2) to play music for music will be amplified by IC3 (AD 2002) to drive the speaker.

The diode D1 and D2 in combination drops to 1.4 V for the nominal voltage (3.5 V) to the UM66. UM 66 can not support more than 4V.

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USB Audio Interface based DAC PCM2902

This is the circuit quality preamplifier with built-in USB DAC for my Leachamp power amplifier. Scheme is PCM2902 datasheet. Circuit includes DAC and ADC, SPDIF input and output of HID and with 3 buttons + MUTE, VOL-and VOL.

For playback of high quality needed for external low-drop voltage stabilizer for the DAC. LP2951CM DAC is used, which was readily available in local stores. Output voltage is fixed at about 3.7 V with two resistors. Circuit board is designed with regard to the placement of good land, and the separation of digital and analog ground. These earth are connected in a single point in a USB connector.

The PCM2902 data sheet is recommended to connect a low pass filter the DAC output to filter high frequencies above audioband produced by the conversion of oversampling. Digital integrated circuits that includes LPF filter frequency above 100 kHz. In the Notes application filter on the pages of the manufacturer recommends first-order LPF (simple RC) or 2 nd order with amplifiers operating as a preamp that works well. I simple RC LPF with the recommended values ​​R and C 1k 4N7. It is best to use the scroll-type ceramic capacitor in place. I did not hear the difference in sound between the connection filter or not, but with respect to other components in an audio chain is best used. For maximum cutoff frequency that can change the capacitor value of 3n3

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Power Supply Failure Alarm

Most of the circuit power supply failure alarm circuits require additional or external power supply. However, this circuit requires no additional power supply. The circuit uses a voltage of 5 volts to 15 volts. To adjust the voltage of this circuit, first connect the power source (5 to 15V) and change the position of potentiometer VR1 until the buzzer buzzer On to Off position.

If the power supply fails, resistor R2 will bias the transistor and the base will turn on the buzzer. Here is a picture series of power supply failure alarm :

 Power Supply Failure Alarm  Circuit

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20W Surround audio amplifier with SI 1020G

Have you been use the IC above? if those who have not, IC above is used or applied to the audio power amplifier. IC processing is quite good for use on amplifier home, or room. IC used is SI1020G who have not very high output with only 20W 8 ohm impedance speakers. Supply voltage ranging from 12 volt to 23 volts.

Below schematic audio amplifier with IC SI1020G

Part List

R1 = 100K

R2 = 1R

C1 = 2u2F

C2 = 100uF
C3 = 47uF

C4 = 10uF
C5 = 2200uF
C6 = 47uF

C7 = 100uF 

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Hot Water Level Indicator

Notes:
Save fuel bills and the economy of the planet with this circuit. SW1 is a normally open press button switch which allows you to view the level of hot water in a hot water tank. When pressed the voltage difference at the junction of the thermistor and preset is compared to the fixed voltage on the op-amps non-inverting input. Depending on the heat of the water in the tank, the thermistors resistance will toggle the op-amp output to swing to almost full voltage supply and light the appropriate LED.

Construction:
Masking tape was used to stick the bead thermistors to the tank. Wires were soldered and insulated at the thermistors ends. A plastic box was used to house the circuit. Battery life will probably be 4 to 5 years depending on how often you use the push switch, SW1.

Sensor Placement:
Thermistors NTC1-4 should be spread evenly over the height of the tank. I placed NTC1 roughly 4 inches from the top of my tank and the others were spaced evenly across the height of the hot water tank. As hot water rises the lowest sensor indicates the fullest height of hot water and should be about 8 to 10 inches from the bottom of the tank.

Calibration:
With a full tank of hot water adjust P1-4 so that all LEDs are lit. As hot water rises, the sensor at the bottom of the tank will be the maximum level of hot water. "Hot" can be translated as 50C to 80C the presets P1-4 allow adjustment of this range.

Parts:

I have used a quad version of the LM324 but any quad opamp can be used or even four single op-amps.
R2-R5 I used 330ohm resistors, but value is not critical. Lower values give brighter LED output.
NTC1-4 The thermistors maximum resistance must roughly equal the resistance of the fixed resistor and preset. As negative temparature coefficient (NTC) thermistors are used, then their resistance decreases for increases in temperature. I used a thermistor from the Maplin Catalogue. Cold resistance was around 300K, hot resistance 15k. Alternative thermistors may be used with different resistance ranges, but the presets P1 to P4 must also be changed as well.

R7-10 series resistance, only required if your thermistors resistance is several ohms at the hottest temperature.
P1 - P4 Chosen to match the resistance of the thermistor when cold.
R1 & R6. These resistors are equal and bias the op-amp inverting input to half the supply voltage. I used 100k.

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Automatic Water Pump Controller

Automatic water pump controller is a series of functions to control the water pump otamatis in a reservoir or water storage. As the water level sensor made with a metal plate mounted on the reservoir or water tank, with a sensor in the short to create the top level and a detection sensor for detecting long again made the lower level and ground lines connected to the bottom of reservoirs or reservoir. The series of automatic water pump controller is designed with 2 inputs NOR by 4 pieces and relay that is activated by the transistor. Automatic water pump circuit requires +12 VDC voltage source and can be used to control the water pump is connected to AC power jalringan. Here is the complete series of pictures.

Series Automatic Water Pump Controller

Sign Component Automatic Water Pump Controller
R1 = 15K
R2 = 15K
R3 = 10K
R4 = 1K
D1 = LED
D2 = 1N4148
Q1 = BC337
IC1 = 4001
SW = SPDT Switches
Relay RL1 = 12V

The working principle series of automatic water pump controller above is. At the time the water level is below both sensors, the output IC1C (pin 10) will be LOW, Kemudin when the water began to touch the lower level sensor, the output IC1C (pin10) remains LOW until the water touches the sensor level above, then the output IC1C (pin 10) going HIGH and active relay through Q1 and turn on the water pump to meguras reservoir. At the muli down and water level sensors for water untouched MKA IC1C output (pin 10) remains HIGH until the new water untouched semuasensor IC1C output (pin 10) LOW and water pump died. The series of automatic water pump controller is equipped with SW1 which serves to reverse the logic of drains (the output of IC1C) and the concept of water supplied (output dri IC1D). When SW1 is connected to IC1D the water pump will turn on when the water does not touch all the sensors and will die when all the sensors tesentuh water. Automatic water pump controller can be used to fill or drain the water according to which mode is selected via SW1.

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Parts Needed for Motion Detector Circuit

This is a circuit which can detect any motion or movement. Its most common use is to detect a person moving through an area where the motion detector can sense.

For example, the motion detector may be placed near a door, so that if any person passes through this doorway, the motion detector will be triggered.

The main electronic component we will use that allows us to pick up this detection is the PIR motion sensor. The PIR motion sensor is a sensor which detects movement through picking up infrared waves. Being that a person emits infrared waves, the detector is able to detect these waves and react, according to the how the circuit is designed to react. The sensor can also pick up the movement of inanimate objects as well, such a rolling ball, because as those objects move, friction acts on them, generating heat. This heat emits infrared radiation, which the PIR sensors may be able to detect if great enough.

In our basic circuit, when the motion detector circuit picks up movement, a red LED will flicker on. 

Parts Needed for Motion Detector Circuit

• PIR motion sensor
• LED
• 470Ω Resistor
• 6V of DC power

The PIR motion sensor is, again, a sensor which can detect movement through picking up infrared radiation. Being that people naturally give off radiation, because of our generated body heat, the motion can easily detect people walking and moving through a vicinity within the sensors range.

The motion sensor has a sensitivity range up to 20 feet (6 meters) and a 110° x 70° detection range, making it a wide lens detection sensor. This means it can measure 110° vertically (from top to bottom) and 70° horizontally (from left to right). The best way to check its sensitivity is when the circuit is built, try moving around through all of its angles. See at which angles it can detect your movement and at which angles it is not able to detect your movement, meaning your out of its angle scope. A lot of it is trial and error and experimenting. Once you know where it can and cannot detect, you can place it in an optimal place where it can detect in areas where you want it to.

The PIR motion sensor is a 3-pin device

Pin 1 is the pin which receives the positive DC voltage. The PIR motion sensor needs between 5V-9VDC of power for operation. In our case, we will use about 6V of power. This can be obtained from switching a DC power supply to 6V or using 4 AA batteries connected in series. We will then feed this voltage into pin 1 of the PIR module.

Pin 3 is the negative DC voltage or ground pin of the device. We connect the negative terminal of the power source to this pin, for a return path.

Pin 2 is the Output pin of the PIR module. This is where the output of the PIR will leave from. When motion is detected by the PIR, its output will go high to 3V. When no motion is detected, its output low and it gives off practically no voltage. When high you can see then how it can power a load, such as an LED to light. This way we can know when it has detected motion or not.

In our circuit, we will connect a 470Ω resistor in series with an LED to the output pin of the PIR sensor. When motion is detected, the output of the PIR sensor will swing high and power and light the LED.

Circuit Diagram

Here you can see anywhere from 5V-9V is fed into the power pins.

Connected to the output pin is an LED. We place a 470Ω resistor in series to limit current so that the LED doesnt receive excess current.

In this circuit, when motion is detected, the output voltage swings high and powers the LED. After about 1 second or 2, the output swings back low and the LED turns off until motion is detected again. Without any motion, the LED just stays off.

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