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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... |
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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. |
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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. |
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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. |
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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. |
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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. |
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Assortment of Siren Circuits |
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Audio MilliVoltmeter - For Testing Amplifiers
(etc), An analogue design, 3mV to 30V with dB scale |
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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. |
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Basement Doorbell - This circuit will activate a
beeper in the basement, whenever the front doorbell
is pressed. |
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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. |
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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… |
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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… |
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Bells Ring Generator - Three circuit options.
Can be synchronized to Christmas tree flashing
lights. |
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Birdie Doorbell Ringer |
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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. |
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Buzzer |
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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. |
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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.. |
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Continuity Buzzer is Frugal with Power - 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. |
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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.. |
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Counter with Doorbell |
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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. |
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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. |
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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!" |
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DIN Audio Pinouts |
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Ding-Dong Bell |
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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 |
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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.. |
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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.. |
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Doorbell Indicator-Remote |
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Doorbell with Counter |
