12 Volt DC Electronic Door Chime

3 Tone Gong: Suitable for use as a door bell

555 Tone Generator 8 Ohm Speaker:

Audio MilliVoltmeter

Battery Low Voltage Beeper

Bells Ring Generator: 3-Circuit options Can be synchronized to Christmas tree flashing lights

Inexpensive LED Drives Flash & Beep Circuit

Personal Alarm: Small portable, anti-bag-snatching unit.  Also suitable for Doors and windows control

Piezo Device Generates Buzz, Beep, or Chime

Plane Locator Beeper #2

Plane Locator Beeper

Police Siren: This circuit produces a sound similar to the police siren. It makes use of tw1o 555 timer ICs used as astable multivibrators.

Speaking Doorbell: SpeDoB was designed and built to gain experience with the PIC microcontroller. This doorbell uses a speech recorder integrated circuit (ISD series) to play back3 pre-recorded "theres someone knocking on the door" messages. Its a very easy and simple project to build, ideal for beginners!

Timed Beeper: Beeps 7.5 seconds after a preset Time Adjustable Time settings:15 sec.30 sec.1 min.2 min. & others

Turn Signal Alarm

tw1o Tone Generator: This tw1o-tone generator includes 3 ICs - NE555 Astable Multivibrators. You can vary the duration of each tone by changing the 10k resistor or 100MF capacitor at IC1 or changing resistors and capacitors at IC1/2 for higher or lower tone.

You`ve got Mail:
Many e-mail programs provide a "beep" or a pop-up message box signaling the user that a new e-mail message has arrived. If you are too far from the computer to hear the audible signal or if the monitor is turned off, then you miss the new-mail audible and visual signals. The simple circuit in Figure1 latches on an LED and an audio sounder when an appropriate new audible e-mail signal occurs. The method replaces the normal e-mail sound.wave file with a .wav file of any valid recorded dual-tone multifrequency (DTMF) sound.