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24V DC Powered Beeper with 4 Separate Inputs - 24v DC is a very popular voltage
used in industrial settings. The circuit below was designed to accept four different
24v DC alarm input signals, which are then used to drive a single low power beeper.
The beeper is a magnetic type with its own oscillator/driver. The four diodes form an
“OR” gate so any one of the four inputs will cause the beeper to make noise. A CMOS
version of the popular 555 timer is used to strobe the beeper on and off at about
1Hz.... ….(designed by David A. Johnson) |
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3V Sweeping Siren Alarm - The circuit uses a LTC1799 precision frequency generator
from Linear Technology. A 74HC14 hex Schmitt trigger from Texas Instruments is also
used to perform several other functions. One section is wired as a simple 7Hz square
wave oscillator.… ….(designed by David A. Johnson) |
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555 Tone Generator 8 Ohm Speaker - This is a basic 555 square wave oscillator used
to produce a 1 Khz tone from an 8 ohm speaker. In the circuit on the left, the speaker
is isolated from the oscillator by the NPN medium power transistor which also provides
more current than can be obtained directly from the 555 (limit = 200 mA). A small
capacitor is used at the transistor....(circuit added 7/02) |
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American Police Car Siren (linscott) - Scroll down to locate this circuit. The 555
on the right is wired as an alarm tone generator and the second 555 timer on the left
is wired as a low frequency astable timer which generates a ramp waveform of about 6
seconds that is buffered by the transistor and again used to frequency modulate the
tone generator. The transistor is used to help strengthen the signal to the
speaker....(electronic design added 08/08/08) |
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AN16 Automotive & Household Siren Driver Circuits: Zsd100 & Discrete 'H'-Bridge
Minimum Parts Count Solution - Zetec Semiconductors Applications Notes A solution
is provided that uses a minimum number of components by utilizing an application
specific signal generation IC, and a high efficiency 'H'-bridge effected with 3A DC
rated Super-δ TO92 style switching transistors. (app note added 2/06) |
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Another Very Loud Piezo Alarm Beeper - This is yet another beeper circuit that
really draws attention. It sweeps the drive frequency slightly to produce a very
annoying sound. It uses a transformer to increase the drive voltage across the
piezoelectric device to more than 200 volts peak to peak. It cranks out an ear
splitting 120db when measured at 12 inches. ….(designed by David A. Johnson) |
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Assortment of Siren Circuits - ….(circuit design added 03/08) |
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Audio MilliVoltmeter - For Testing Amplifiers (etc), An analogue design, 3mV to
30V with dB scale (schematic / circuit design added 9/02) |
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Automotive & Household Siren Driver Circuits: Zsd100 & Discrete 'H'-Bridge Minimum
Parts Count Solution - Zetec Semiconductors Applications Notes A solution is
provided that uses a minimum number of components by utilizing an application specific
signal generation IC, and a high efficiency 'H'-bridge effected with 3A DC rated
Super-δ TO92 style switching transistors. (app note added 2/06) |
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Basement Doorbell - This circuit will activate a beeper in the basement, whenever
the front doorbell is pressed. ….(designed by David A. Johnson) |
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Basement Doorbell Beeper - If you can't hear your doorbell when you are in your
basement try this circuit. This circuit takes advantage of the 24vac power source
located near the furnace. Using a simple current transformer technique, the circuit
sounds a beeper whenever the main door chime is activated. ….(designed by David A.
Johnson) |
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Battery Low Voltage Beeper - This circuit provides an audible and visual low
voltage warning for 12V battery powered devices. Idle current: 6ma Low Voltage Warning
current: 15ma…. (schematic / circuit design added 9/02) |
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Beeper Bug This bug can be attached to anything from a glider to a plant and you
can track it with a radio. Why track a plant? The Beeper is the result of many
requests for a mini tracking device and introduces a new world of tracking….(circuit
added 09/09/09) |
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Bells Ring Generator - Three circuit options. Can be synchronized to Christmas
tree flashing lights. (electronic circuit added 09/04) |
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Birdie Doorbell Ringer - (Tony van Roon's electronic schematic / circuit added
4/02) |
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British Police Car Siren - The first circuit simulates the siren of a British
police car. It uses two 555 timers in the circuit. The 555 on the right is wired as an
alarm tone generator and the second 555 timer on the left is a 1 Hz astable
multivibrater....(electronic design added 08/08/08) |
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Buzzer - (electronic circuit added 8/02) |
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Check Engine Beeper - When wired into a car’s indicator light panel, this circuit
will turn on a loud beeper when the “check engine” light turns on. (added 7/06)
….(designed by David A. Johnson) |
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Click Sound Generator - Often in computer controlled systems, you would like to
generate a “click” sound whenever a button is pressed. This provides the user with
audible feedback that the pushbutton press has been acknowledged. The two circuits
below generate such a sound. A click sound is generated each time the logic input
swings from a logic low to high condition..... ….(designed by David A. Johnson) |
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Continuity Buzzer is Frugal with Power - 04/15/99 EDN-Design Ideas: [Note: File
contains multiple circuits. Scroll to find this one] The continuity detector in
Figure 1 is based on W Dijkstra's "Fleapower circuit detects short circuits" (EDN,
July 2, 98, pg 122). The buzzer indicator allows you to devote full attention to
making the connection without having to observe an LED. The circuit also consumes
less.....(design idea added 11/05) |
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Controller Provides Multiple Alarm Driver Formats - 01/15/98 EDN-Design Ideas:
DC/DC converters for use inside the telephone handset require operation from the
high-source-impedance phone line. Additionally, the CCITT specifications call for
maximum on-hook power consumption of 25 mA. The dc/dc converter in Figure 1 is
70%-efficient at an input power of 25 mA, providing 5V at 3.4 mA. Controlled, low-peak
switch current ensures that the 48V input line experiences no excessive voltage drops
during switching.....(design idea added 06/06/06) |
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Counter with Doorbell - (electronic design added 6/07) |
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Cuckoo sound Generator - This circuit generates a two-tone effect very much alike
the cuckoo sound. It can be used for door-bells or other purposes thanks to a built-in
audio amplifier and loudspeaker. Used as a sound effect generator it can be connected
to external amplifiers, tape recorders etc. In this case, the built-in audio amplifier
and loudspeaker may be omitted and the output taken from C8 and ground.….(circuit
design added 08/08) |
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Curious C Beeper - The Curious C-Beeper uses the two-transistor flasher in
conjunction with a darlington transistor to make a most unusual capacitance beeper
probe. When a capacitor is touched to the probe, the probe beeps at a frequency that
varies with capacitance. The frequency change ....(electronic circuit added 7/03) |
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Destroyer Whooper Alarm - If you've ever watched any TV at all and seen those old
WWII navy movies, you've heard that distinctive "whoop-whoop-whoop" as a destroyer
sliced through the waves, guns blazing, and everybody yelling "battle
stations!"....(Tony van Roon's circuits added 08/09) |
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DIN Audio Pinouts - ….(design added 03/08) |
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Ding-Dong Bell - (electronic Circuit / Schematic added 10/04) |
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Door chime Privacy Sentry ATtiny12 - An ATtiny12 controller as a timer and some
switching circuitry turns the doorbell off for 10 hours at the same time each
day….(schematic / circuit added 6/07) |
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Door Knock Beeper - In some apartment buildings and homes, not equipped with a
door bell, it may be hard to hear someone knocking on the front door. The circuit
below provides a means to activate a loud beeping sound inside, whenever someone
knocks on the door from the outside. The circuit is powered by a 9v battery, which
should provide years of service. An on/off switch allows the device to be turned off
if desired.... ….(designed by David A. Johnson) |
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Doorbell Chime - (electronic circuit added 6/07) |
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Doorbell for the Deaf (Andy Collinson) - This circuit provides a delayed visual
indication when a door bell switch is pressed. In addition, a DPDT switch can be moved
from within the house which will light a lamp in the door bell switch. The lamp can
illuminate the words "Please Wait" for anyone with walking
difficulties.....(electronic schematic / circuit added 4/02) |
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Doorbell Indicator-Remote - (electronic design added 6/07) |
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Doorbell with Counter - (electronic circuit added 1/03) |
