Newest circuit diagrams

Volumetric Sensor Alarm

Detects small variations in air pressure. Can be battery powered (6/12V)

Mini Touch Alert

Connecting it to the door handle, it constitutes an effective as economic alert for your room, office, lab, or even drawer.

High Quality Intercom

A very high quality intercom, which may also be used for room monitoring.

One second Audible Clock

A beep or metronome-like click and/or a visible flash, will beat the one-second time.

Adjustable Constant Current Load

An adjustable power load is a piece of test equipment that often comes handy in the development of certain electronics projects. For example, when you are building a power supply, it will come a time when you need to "simulate" a load to see how well your design performs as the load varies. Adding power resistors to the output can sometimes do in a pinch, but often you will not have the right resistor value handy with the right power rating for the test. This is where an adjustable electronic load comes handy. In this article, I'll show how you can build one using common components available to the electronics hobbyist.

Battery Powered Burglar Alarm

This is a single zone alarm - with independently adjustable Exit, Entry and Siren Cut-Off timers. It will accommodate the usual types of normally-closed input devices - such as magnetic-reed contacts, foil tape and PIRs.

Expandable Multi-Zone Modular Burglar Alarm

The Basic Alarm Circuit has an automatic Exit/Entry Zone - an Instant Alarm Zone that will accept both normally-closed and normally-open triggering devices - and an "Always On" 24-hour Personal Attack/Tamper Zone. By using the Expansion Modules - you can add as many extra alarm zones as you require.

Infra-red Level Detector

Useful for liquids level detection and proximity devices Up to 50 cm. range, optional relay operation

Privacy Circuit

A privacy circuit allowing one telephone exclusive access to the line.

Sound of Light Circuit

The circuit uses a solar cell as the input transducer, blocks the DC produced by the cell, but amplifies the light received by the cell. Sunlight, moonlight, torchlight all produce sound which is amplified by this circuit.