A simple single-tone siren for notifying important events. A variety of simple circuits on the NE555 Description of the operation of the alarm on the NE555

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Chip NE555(analogue of KR1006VI1) - a universal timer, designed to generate single and repeating pulses with stable time characteristics. It is not expensive and is widely used in various amateur radio circuits. It can be used to assemble various generators, modulators, converters, time relays, threshold devices and other electronic equipment components...

The microcircuit operates with a supply voltage from 5 V to 15 V. With a supply voltage of 5 V, the voltage levels at the outputs are compatible with TTL levels.

Dimensions for different types of housings

CASE - DIMENSIONS
PDIP (8) - 9.81 mm × 6.35 mm
SOP - (8) - 6.20 mm× 5.30 mm
TSSOP (8) – 3.00 mm× 4.40 mm
SOIC (8) – 4.90 mm× 3.91 mm

NE555 block diagram

Electrical characteristics

PARAMETER	TEST CONDITIONS		SE555			NA555 NE555 SA555			UNITS MEAS.
PARAMETER	TEST CONDITIONS		MIN	TYP	MAX	MIN	TYP	MAX	UNITS MEAS.
Voltage level at THRES pin	V CC = 15 V		9.4	10	10.6	8.8	10	11.2	IN
Voltage level at THRES pin	V CC = 5 V		2.7	3.3	4	2.4	3.3	4.2	IN
Current (1) through THRES pin				30	250		30	250	nA
TRIG pin voltage level	V CC = 15 V		4.8	5	5.2	4.5	5	5.6	IN
	V CC = 15 V	T A = –55°C to 125°C	3		6
	V CC = 5 V		1.45	1.67	1.9	1.1	1.67	2.2
	V CC = 5 V	T A = –55°C to 125°C			1.9
Current through TRIG pin	at 0 V on TRIG			0.5	0.9		0.5	2	µA
Voltage level at the RESET pin			0.3	0.7	1	0.3	0.7	1	IN
Voltage level at the RESET pin	T A = –55°C to 125°C				1.1				IN
Current through RESET pin	with V CC on RESET			0.1	0.4		0.1	0.4	mA
Current through RESET pin	at 0 V on RESET			–0.4	–1		–0.4	–1.5	mA
Switching current on DISCH in closed state				20	100		20	100	nA
Switching voltage on DISCH in open state	V CC = 5 V, I O = 8 mA						0.15	0.4	IN
Voltage on CONT	V CC = 15 V		9.6	10	10.4	9	10	11	IN
	V CC = 15 V	T A = –55°C to 125°C	9.6		10.4
	V CC = 5 V		2.9	3.3	3.8	2.6	3.3	4
	V CC = 5 V	T A = –55°C to 125°C	2.9		3.8
Low output voltage	V CC = 15 V, I OL = 10 mA			0.1	0.15		0.1	0.25	IN
	V CC = 15 V, I OL = 10 mA	T A = –55°C to 125°C			0.2
	V CC = 15 V, I OL = 50 mA			0.4	0.5		0.4	0.75
	V CC = 15 V, I OL = 50 mA	T A = –55°C to 125°C			1
	V CC = 15 V, I OL = 100 mA			2	2.2		2	2.5
	V CC = 15 V, I OL = 100 mA	T A = –55°C to 125°C			2.7
	V CC = 15 V, I OL = 200 mA			2.5			2.5
	V CC = 5 V, I OL = 3.5 mA	T A = –55°C to 125°C			0.35
	V CC = 5 V, I OL = 5 mA			0.1	0.2		0.1	0.35
	V CC = 5 V, I OL = 5 mA	T A = –55°C to 125°C			0.8
	V CC = 5 V, I OL = 8 mA			0.15	0.25		0.15	0.4
High output voltage level	V CC = 15 V, I OH = –100 mA		13	13.3		12.75	13.3		IN
	V CC = 15 V, I OH = –100 mA	T A = –55°C to 125°C	12
	V CC = 15 V, I OH = –200 mA			12.5			12.5
	V CC = 5 V, I OH = –100 mA		3	3.3		2.75	3.3
	V CC = 5 V, I OH = –100 mA	T A = –55°C to 125°C	2
Current consumption		V CC = 15 V		10	12		10	15	mA
		V CC = 5 V		3	5		3	6
	Output low, no load	V CC = 15 V		9	10		9	13
	Output low, no load	V CC = 5 V		2	4		2	5

(1) This parameter affects the maximum values of timing resistors R A and R B in the circuit Fig. 12. For example, when V CC = 5 V R = R A + R B ≉ 3.4 MOhm, and for V CC = 15 V the maximum value is 10 mOhm.

Performance characteristics

PARAMETER		TEST CONDITIONS (2)	SE555			NA555 NE555 SA555			UNITS MEAS.
PARAMETER		TEST CONDITIONS (2)	MIN.	TYPE.	MAX.	MIN.	TYPE.	MAX.	UNITS MEAS.
Initial error time intervals (3)		T A = 25°C		0.5	1.5 (1)		1	3	%
Initial error time intervals (3)				1.5			2.25		%
Temperature coefficient of time interval	Each timer, monostable (4)	T A = MIN to MAX		30	100 (1)		50		ppm/ °C
Temperature coefficient of time interval	Each timer, astable (5)			90			150		ppm/ °C
Changing the time interval depending on the supply voltage	Each timer, monostable (4)	T A = 25°C		0.05	0.2 (1)		0.1	0.5	%/V
Changing the time interval depending on the supply voltage	Each timer, astable (5)			0.15			0.3		%/V
Output pulse rise time		C L = 15 pF, T A = 25°C		100	200 (1)		100	300	ns
Output pulse decay time		C L = 15 pF, T A = 25°C		100	200 (1)		100	300	ns

(1) Conforms to MIL-PRF-38535 and has not been field tested.

(2) For conditions specified as Min. and Max. , use the appropriate value specified in the recommended operating conditions.

(3) The error of the time interval is defined as the difference between measured meaning and average value random sample from each process.

(4) Values are for a monostable circuit with the following component values R A = 2 kΩ to 100 kΩ, C = 0.1 μF.

(5) Values are for an astable circuit with the following component values R A = 1 kOhm to 100 kOhm, C = 0.1 µF.

Metal detector on one chip

Coil diameter 70-90 mm, 250-290 turns of wire in varnish insulation (PEL, PEV...), with a diameter of 0.2-0.4 mm.

Instead of a speaker, you can use headphones or a piezo emitter.

Video of this metal detector in action

Voltage converter from 12V to 24V

Toy animation

Together with counter 4017 and 555, you can make a “running fire” to animate some kind of toy or souvenir. When the power is turned on, the 555 generator starts running for just a few minutes, then turns off. At the same time, the current consumption drops - the batteries will last for a long time. The time is set with a 500 kOhm variable resistor.

Light controlled generator

Dark detector with LM555. This scheme will generate sound when light hits the Cds photo sensor.

This circuit generates alarm when The light from the sun, fire or lamp hits the LDR sensor. And the 555 has a multivibrator with a generation frequency of about 1 kHz when detecting light. When exposed to light, the sensor closes the circuit and the 555 generates oscillations around 1 kHz via open transistor BC158.

Musical keyboard

A very simple musical instrument (keyboard) for playing music can be made using a 555 chip. You can build an unusual musical instrument in the photo above. Graphite is used as a keyboard and a sheet of paper with notes is represented as holes in the paper.

The same circuit, but with ordinary resistors and buttons.

Timer for 10 minutes

The timer is started by button S1 after 10 minutes. LED1 and LED2 blink alternately. The time is set by a 550 kOhm resistor and a 150 µF capacitor.

Car alarm simulator

The LED flashes as if the car has an alarm. Install the LED in a visible place. The thief will see that the car is under alarm and will avoid it :)

A simple police siren simulator

The circuit is assembled on a breadboard.

Using two NE555s you can make a simple police siren generator. It is recommended that you make the following timer parameters: R1=68 kOhm (timer No. 1) is set to slow generation mode and the timer with R4=10 kOhm (timer No. 2) is set to fast generation mode. MYou can change the timer characteristics. The output frequency is changed by a chain of resistors R1, R2 and C1 for timer components No. 1 and R4, R5 and C3 for timer No. 2.

A similar circuit below with a transistor at the output:

Liquid Level Sound Generator

You can

Installation of collectors on the roof is usually carried out by specialists, but this work can be done on your own by purchasing a set of necessary equipment.

How to extend the “life” of a light bulb? How to repair an incandescent lamp? How to increase the service life of a flashlight?

The answer to these questions is to replace the conventional incandescent lamp with an LED. With one replacement we will immediately “kill two birds with one stone” - our new light bulb will shine and last longer. LEDs have a longer service life and lower current consumption.

Description.

This circuit is a police siren sound simulator based on NE55 Timer IC.The circuit uses two NE555 timer ICs and each of them is connected as a multivibrator. The circuit can be powered from different voltages (from 6 to 15V DC), and with the use of an additional power amplifier, you can get quite loud sound.

IC1 is connected as a low-frequency astable multivibrator with a frequency of about 20 Hz @ 50% (50% square wave) and IC2 has a higher frequency of about 600Hz. The signal from the output of the first multivibrator is connected to the voltage control input (pin5) on IC2.That is, the signal IC2 modulates the signal IC1 creating a siren effect.In simple words, the output frequency of IC2 is controlled by the output of IC1.

Notes.

* The author used 12V DC to power the circuit.
*Instead of using two NE55 timer ICs, you can also use one NE556 timer.
* NE556 is 2 NE555 ICs in one package.
*See the details of NE555 NE556 and have a clear understanding of them.
* Speaker (speaker) can be 64ohm, 500mW to 1W.

Source - http://www.circuitstoday.com/category/555-timer-ic

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The sound siren is used in different places and for a wide variety of purposes to notify about something. It can be adapted to some kind of security system, built into a toy, used as a doorbell, or something else. By assembling this simple one-color siren, we will get a loud and unpleasant sound, just in order to quickly respond to a notification.

A simple siren circuit diagram with a small number of details awaits you in the figure above. Conventionally, the circuit diagram can be divided into two parts: multivibrator - low-frequency amplifier. A multivibrator generates a signal of a certain frequency, and the amplifier, in turn, amplifies it. The result is a loud sound with vibrations of about 2000 Hz.

Our multivibrator generates pulses by quickly opening/closing BC547 transistors. The frequency is mainly related to the capacitance values of the capacitors and partly from the base resistors and the transistors themselves. In the circuit, the standard capacitance C1 and C2 = 10 nF and 22 nF; by varying these values, the tone of the electric siren is also adjusted. You can receive it from the collector of any of the transistors (VT1/VT2). In this device, the signal goes through a resistor further to the ULF stage. The amplifier is based on two very common bipolar transistors BC547 and BD137.

Here are some computational parameters of the multivibrator. The frequency is approximately 959.442 Hz (the multimeter shows 1-1.1 kHz on the collector of the made generator), duty cycle S = 1.45, period T = 0.000104. This information may differ depending on the transistors used, other deviations in the characteristics of radio components... Almost everything affects the sound frequency. The current taken from the circuit's power source can reach up to 0.5 Ampere at 12 Volts.

Circuit and board in Proteus (file ISIS And ARES ): (downloads: 212)
Three-dimensional board in 3DS : (downloads: 127)

The NPN structure transistor from the low-frequency amplifier will heat up when the siren is activated, so we put it on a heat sink; I use a powerful and large C5803.

Now about replacing some parts. Here you can replace a lot of things, for example, we take almost any transistors in the gene (npn) KT315, BC548 and KT3102 - they will all work perfectly. The analogue of BC327 in this circuit will be BC558/BC557/KT3107. BD139 is generally replaced with the same power or more. The capacitance of the capacitors will change the frequency, there is also a lot of choice, experimenting to select the preferred sound. The resistors may change a little, but remember that in the first part of the circuit the resistance of R1 and R4 should be less than R2, R4.

We reproduce the sound of the siren on any speaker that is available, R of the coil is 8-25 Ohms. I tried with a wide variety of both from a radio receiver and from a home landline telephone. Also try testing a piezoelectric element as a sound emitter; be sure to attach a resonator to it (you can use a housing).
Very quiet siren? No problem! We take a ready-made ULF, for example, some kind of tdashka (the digital audio). Their variety is amazing, from small chips in DIP-8 at 1 Watt, to large ones with a power of more than 100 Watts. I would advise taking something average, TDA2003 (up to 10W) or TDA2030 (up to 18 Watt). Don’t forget to look at what kind of power is needed for this or that sound “amplifier”.

Appearance of a mounted mounted siren:

Power supply from 6 to 12 Volts (with a larger one it also works fine). Output power up to five watts. When using rechargeable batteries/batteries, we get an autonomous siren that can operate without mains voltage. If we provide power from 220V, then we take a ready-made power supply or remake the phone charger by replacing the zener diode with the required voltage.

Siren demonstration, video: