Sound: Activated Electronic Switch

Adjust the sensitivity of this circuit to control a Relay that can turn on whatever is connected to the contacts of the relay. Very practical circuit for a variety of projects. Turn on a light when your dog barks, or set of a siren when an intruder makes

This mini-VOX - voice operated relay - is based on a circuit published in Silicon Chip, 9/1994, p31.

Both a touch and a contact switch are built on one PC board so that the builder can see how each works. A battery can power the contact switch but you'll need an AC power supply for the touch switch to work well. The circuit switches a relay with a 3 Amp

Three relay-based electronic switching circuits that switch according to light levels.

Easy to build Gun Sound Effects generator kits, also inludes several different sounds and tunes.

Sound turns on the transmitter, which operates in the FM radio band. A neat way to catch a thief in another room or garage. The volume of sound needed to trigger the circuit is adjustable. The two stage transmitter has good range and the circuit powers do

Easy to build sound effect generator kits, inludes several different sounds and tunes.

Easy to build sound effect generator kits, inludes several different sounds and tunes.

Easy to build sound effect generator kits, inludes several different sounds and tunes.

Extremely useful electronic circuit capable of producing a variety of cool sound effects.

This super cool circuit behaves as a clapper-switch. You clap and the circuit turns on. Clap and it turns off. Great as a light clap switch.

This circuit is an alarm for the home, car and a lot more. It employs a magnet and reed switch to trigger the circuit. An intergral piezo sounder produces the alarm sound (100dB). There is also a relay capable fo handling up to 10 amps that will switch wh

Simple schematic for a doorbell electronic circuit that produces a ding-dong sound when your visitors presses the door-bell button. Based on IC 8021-2.

This page links to two electronic circuits. Once circuit produces emergency siren noises (police, fire, ambulance), and the other is a chime type sound effect.

An electronic circuit that uses a 556 (Dual timer) IC to produce a two-tone train horn sound effect. Equivalent circuit using two 555 timers (single timers) is given.

Power on/off almost anything with this infrared controlled electronic switch. Some spell it Infared!

This is the Brodcast Warehouse All-in-One PCB 1 Watt FM Transmitter. This item has a built in limiter / compressor & stereo encoder!

A stronger, Mecha-Medusa is a walking robot that operates with the aid of a sound sensor. Clap hands or snap fingers to command this robot to start walking on four legs. Stops automatically after a preset time. Ideal for the hobbyist or budding scientist.

The circuit uses a matched pair of 40 Khz transducer elements to detect movement up to 22 feet away. You may add a relay (not included) to switch higher voltage loads. The unit switches a LED for movement indication. Sensitivity is setable via control. Cr

Dick Cappel's page illustrates an extremely basic small FM transmitter that rebroadcasts sounds using a 1.5 Volt battery. very simple circuit.

This circuit will play a tune when light strikes a light dependent resistor, such as when a music box lid is opened.