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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
Basics-Sunthesizer - A Phase Locked Loop (PLL) consists of a Voltage Controlled Oscillator (VCO) , the output frequency of which is monitored and controlled. An error voltage steers the VCO and brings it back onto the correct frequency. The error voltage is generated by a Phase Sensitive Detector (PSD) which compares the VCO frequency with a reference frequency. __ Designed by Harry Lythall-SM0VPO
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
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
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
Egyption Talking Frog Box - This device 'listens' to a conversations and then interjects words and phrases at inappropriate times. __ Designed by Luhan Monat-Mesa Arizona
Electronic Canary Doorbell - This circuit is a modified "Hartley Oscillator" with a couple extra parts. T1, the LT700 (Tony van Roon's or equivalent, is a small center tapped (Tony van Roon's ct) audio transformer with an impedance of 1000 ohms at 1000 hertz. The secondary of this transformer has an impedance of 8 ohms. Usually noted as 1K:8 ct. I tried a couple other models like the red and green types (Tony van Roon's taken out of a $5 made-in-china am pocket radio) and they both work good. You may have to adjust the caps to get the sound __ Designed by Tony van Roon VA3AVR
Electronic Canary Sound Effects - 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
Electronic Chime - Scroll Down to find this circuit. This circuit simulates a chime similar to the sound many cars make when the keys are left in the ignition. The bottom two gates form a squarewave audio oscillator that drives the base of the 2N4401, turning it on and off at an audio rate. The top two gates produce a short low-going pulse about once per second that discharges the 10 uF capacitor through the diode. The voltage then jumps up and slowly decays __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Electronic Dog Whistle - Need electronic dog whistle? it is widely known that dogs can hear sounds with frequencies higher than the humans cant hear. Sound frequencies higher than 20 kHz can be hardly detected by humans but animals are very sensitive to it. Basing this fact, an electronic dog whistle can be constructed and used to call dogs back from __ Designed by D Mohankumar
Electronic glow-worm - Here is a circuit that simulates the chirping and glow of a glow-worm bug. __ Designed by Electronics Projects for You
Electronic Metronome - A metronome is used by musicians for practice in maintaining a consistent tempo, or rubato, around a fixed beat. This circuit produces a regular beat at the rate of 40 to...__ Electronics Projects for You
Electronic Metronome - A Universal Power supply based on the L200 regulator, which includes an outboard pass transistor to boost output currents up to 4 amps. __ Designed by Volker Jeschkeit
Emergency Siren Simulator - This siren circuit simulates police, fire or other emergency sirens that produce an up and down wail. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Frogger Sound/ROM-FROGSND Arcade game (PDF) - Schematic only, no circuit description included. __ Contact jrokweb @ san.rr.com
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