• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Wailing Alarm Siren

Extracts from this document...


Wailing Alarm Siren by Tony van Roon Parts List: R1,R5 = 4.7K C1,C4 = 100uF/25V, electrolytic R2 = 47K C2,C3 = 0.01uF (10nF), ceramic R3 = 10K T1 = 2N3702 (NTE159, TUP, etc.) R4 = 100K IC1,IC2 = LM/NE555, MC1455P, etc Rx = *Notes LS = Loudspeaker. *Notes Notes: This circuit provides a warbling sound to any alarm circuit. IC2 is wired as a low frequency astable with a cycle period of about 6 seconds. The slowly varying ramp waveform at C1 is fed to pnp emitter follower T1, and is then used to frequency modulate alarm generator IC1 via R6. IC1 has a natural center frequency of about 800Hz. Circuit action is such that the alarm output signal starts at a low frequency, rises for 3 seconds to a high frequency, then falls over 3 seconds to a low frequency again, and so on. *The Loudspeaker LS and the resistor marked "Rx" should be together 75 ohms. If you have a standard 8-ohm speaker then Rx is 67 ohms. ...read more.


This varying voltage modulates the frequency of the 2nd IC. This process repeats and what you hear is the sound remarkably similar to the police siren. Two presets VR1 and VR2 are provided to vary the siren period of repetition and the tone of the siren. By varying VR1 you can set how fast the siren changes from high freq. to low freq. VR2 sets the siren frequency. Adjust VR1 and VR2 to suit your taste. External Bellbox Siren/Strobe � Fully self-contained � Extremely loud 114dB piezo sounder � High intensity flashing blue strobe light � Selectable SAB mode or SCB mode � Built-in NiCad backup battery � Adjustable sounder cut-off timer � Flashing comfort LEDs � Robust polycarbonate construction � Protective inner skin � Dual tamper switch protected An attractively styled, external siren box with integral blue strobe light. Fully self-contained, the unit has an adjustable siren cut-off timer and is supplied with comprehensive instructions on connecting to all the most popular alarm panels, a mounting template and fixing screws and wall plugs. ...read more.


Tamper � 3 Part-set programs � Easy to programme An eight-zone fully programmable hardwired alarm kit for use in domestic or small commercial properties. The system features a remote keypad (RKP) that allows the main panel to be hidden away making for a much neater installation. The kit includes all the security components necessary, including step by step installation instructions. The system can be expanded to include up to four remote keypads and a wide range of additional detectors. `` Big Ben Sound This circuit produces the famous Big Ben sound. It produces the "ding dong" sound when switched ON. Basically the circuit alternates between two frequencies which are adjustable. This produces the "ding-dong" sound. The first IC(left) oscillates at about 1Hz. The second IC's tone is modulated by the changing voltage at the output of the first IC. The first IC determines how fast the changeover from one frequency to the other takes place and second IC determines the tone of the final output. By varying the VR1, the changeover rate can be adjusted. By varying VR2 the tone can be adjusted ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Systems and Control section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Systems and Control essays

  1. 555 Timer Practical.

    I will refer to my circuit diagram in order to do this. I will need to look at the different sizes for different components. I will use a mini-pillar drill to drill the holes on the PCB Board, making sure the PCB Board is secured, so that it cannot move before attempting to drill the holes.

  2. Investigate and construct a sensor.

    In addition, I would be recording this in a table, and this would show the voltage against decibels. I would also measure this with the decibel meter by simply placing this the same distance as the microphone away from the loudspeaker.

  1. Electronics Project - Remote Infrared Circuit.

    This circuit also has the addition of another infrared sensor in a potential divider acting as the reset mechanism. I intend to have my whole circuit operating off a power supply of 5 volts. The chip I used is 7474 which incorporates two D type flip-flops.

  2. Bicycle Alarm Project

    The anti-tamper is to be achieved by a micro-switch inside the box that is switched by the removal of the case lid and a foil wire around the alarm and bicycle frame to prevent the alarm being removed. 4.

  1. 'A small business wishes to sell a range of electronic games to help alleviate ...

    The encoder configuration must be the same on the transmitter and the receiver in order for the circuits to work correctly. A single Infra-red LED is preferred because it makes the transmitter more directional. An Explanation of the Circuit (Transmitter)

  2. An electronics firm wishes to introduce a range burglar alarms. This coursework contains the ...

    It must sense intruders entering through the rear door. It must sense intruders passing down the hallway. It must sense intruders entering through the front door. It must sense intruders climbing the stairs. It must sound an alarm that can be heard 50m away (108dB plus).

  1. Design and build an electrical toy for children aged 5 years and over.

    It was made under license in the UK by Waddington's. Darrow died in 1967. 1943 - After researching a suspension device Richard James developed the Slinky. It went on sale in 1945. 1948 - Criss Cross Words which was invented by Alfred Butt (originally Lexico)

  2. Calibrating a Potentiometer sensor.

    As the distance between the two points increases, the resistance increases; this is because the electricity has further to travel against the force of resistance. This is shown in the diagram below. Therefore overall resistance is greater. The shorter the distance the, the less the resistance, using the same reasoning.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work