2 Tone Train Horn -  With this circuit you can electronically simulate the noise of a diesel-train horn.  The sound is triggered automatically as the train reaches a desired place on the track so you can produce the sound as the train approaches stations, level crossings, etc.  The circuit can be built simply by using one 556 or two 555 timers __ Designed by Tony van Roon  VA3AVR

3 Level Audio Power Indicator -  Battery-operated3 LED display that connect it to loudspeaker output __ Contact Flavio Dellepiane, fladello @ tin.it

3-state sound generator -  3-state sound generator with LM556 (dual LM555) __ 

Add speech encoding/decoding to your Design -  02/04/99 EDN Design Ideas:  (Scroll to find this one) Adding speech capabilities to a design can sometimes lead to complex algorithms and expensive DSPs or specialized audio chips.  However, with  completion of a simplified adaptive differential pulse-code-modulation (ADPCM]algorithm, you can now implement se audio capabilities in low-cost 8-bit µCs, which typically.      Page includes several designs.   Design by Rodger Richey, Microchip Technology Inc, Chandler, AZ

Ambulance Siren -  This siren circuit simulates police, fire or other emergency sirens that produce an up and down wail.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Automatic School Bell -  Consider that a school has a total of eight periods with a lunch break after the fourth period.  Each period is 45 minutes long, while the duration of the lunch break__ Electronics Projects for You

Bhajan & Mantra Chanting Amplifier -  People in india like to chant various mantras as they believe it brings good luck, peace of mind and helps in concentration.  Here we present the circuit of an electronic chanting device__ Electronics Projects for You

Big Ben Sound -  This circuit produces  famous Big Ben sound.  it produces  "ding dong" sound when switched ON.  Basically  circuit alternates between two frequencies which are adjustable.  This produces  "ding-dong" sound.  The first C (left) oscillates at about 1Hz.  The second IC 's tone is modulated by  changing voltage at  output of  first IC  __ Designed by Radioland.nt.au

Bird Sound Generator -  A few years back, Wilf Rigter posted this circuit for making bird-like sounds __ Designed by Wilf Rigter

Birdie Doorbell Ringer -  P1 is of experimental value.  Start with 220 Ohms or so and modify to suit your needs.  The transistor is a general purpose kind and is not critical, almost any PNP type will work.  L1 is a bell-transformer which is usually already present in the house.  if you wish, you could use a battery instead of the bell transformer.  Just hookup a 9-volt battery (or wall adapter) to points 'A' and 'B' (A=+) the diode (D1) is to protect the circuit from accidental polarity reversal and is optional, but required as a rectifier for use with the bell transformer __ Designed by Tony van Roon  VA3AVR

Call Sign Annunciator -  in the USA, R/C wireless video hobbyists are required to operate their video transmitters under the FCC Part 97 regulations (amateur radio).  The only exceptions are the Part 15 approved systems, but these low power alternatives are rarely used.  Other countries have similar requirements.  Playing by the rules will certainly prevent conflicts with government officials, since they can levy substantial penalties to offenders.  But more importantly, following the rules is the basis of good amateur radio manners.   __ Designed by RC-CAM T. Black

Canary Sound Effect -  An electronic version of a chirping canary.  May be used as an alarm, a sound effects generator or perhaps a replacement doorbell __ Designed by Andy Collison

Car Back-up Alarm -  The brake lights of  automobile trigger this circuit on and off.   This save  annoyance of  alarm when it is not needed.   This is an older circuit which was published in Popular Electronics Magazine, but still a good circuit today.   __ Designed by Tony van Roon  VA3AVR

Circuit Vocalizes Telephone Number -  02/03/94 EDN Design Ideas:  The circuit in Fig 1 is a simple method of vocalizing the digit number of a telephone keypad, which, for someone visually impaired, provide as heLPFul voice confirmation.  A 75T202 dual-tone multifrequency (DTMF]receiver decodes the DTMF signal when you depress the phone's keypad.  The TC8801N voice synthesizer Design by Shwang-Shi Bai,  Chun-Shan Institute of Science and Technology, Lung-Tan, Taiwan

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 . . . Circuit by Dave Johnson P.E.-January, 2009

Clock Tick-Tock Sound Generator & LED Pendulum -  Wooden-case, battery-operated wall clocks with pendulums are available in the market.  Some even have chimes.  What is missing is the tick-tock sound of old mechanical pendulum clocks.Fig.1 shows the circuit__ Electronics Projects for You

Colour Organ -  Three Lamp-Channels Output - Built-in Electret Microphone __ Contact Flavio Dellepiane, fladello @ tin.it

Crazy Cricket or Freaky Frog -  Love the sound of crickets and frogs (and who doesn't) ? Maybe you will revise your judgement after exposure to Crazy or Freaky - the (very) pesky cricket and equally annoying grenouille.__ SiliconChip

Cricket Chipper Sound Generator -  Here is the aluminum "angle bar" I used.  it's easy to cut and drill.  The size I picked out is 1/16" X 1/2" X 3/4" and the sides are just short of 7".  The notch cut on the angle bar is about 2" in from the front (the length of your servo from front to back mounts).  Your cross pieces can be any length, but I made mine the size of my IC PCB (standard IC PCB from Radio Shack).  __ Credit to Sparky

Cricket Chirping Generator -  Funny gadget for props and jokes.5, 12V Battery operation.   __ Contact Flavio Dellepiane, fladello @ tin.it

Cuckoo-song Generator -  This circuit generates a two-tone effect very much alike the cuckoo song.  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 across C8 and ground.   __ Contact Flavio Dellepiane, fladello @ tin.it

Digital Call Sign Annunciator -  in the USA, R/C wireless video hobbyists are required to operate their video transmitters under the FCC Part 97 regulations (amateur radio).  The only exceptions are the Part 15 approved systems, but these low power alternatives are rarely used.  Other countries have similar requirements.  Playing by the rules will certainly prevent conflicts with government officials, since they can levy substantial penalties to offenders.  But more importantly, following the rules is the basis of good amateur radio manners.   __ Designed by RC-CAM T. Black

Dual-Tone Horn -  This circuit generates two different frequencies and mixes these to produce a balanced ringing tone, which can be used in burglar alarms or call bells. The circuit uses a dual-timer IC LM556__ Electronics Projects for You

Sound Synthesizer Circuits:  #'s - D      E - R      S - Z