FREE
circuits!
Recently added diagrams and projects
August 4, 2010
Attach this circuit to the door of an unattended shop - or reception area - and the sound of the buzzer will tell you when you have a customer. Add a siren - and it... [more]
August 4, 2010
This circuit will let you know when something that should be kept closed - has in fact been left open. Attach it to a Fire-Door. It will allow you to pass through the door as... [more]
August 3, 2010
This is a basic single-zone burglar alarm circuit. Its features include automatic Exit and Entry delays - and an optional Siren Cut-Off timer. It has an extremely small standby current. This makes it ideal for... [more]
August 3, 2010
This is an enhanced version of the simple Garage/Shed Alarm. The Entry and Exit delays have been increased to about 30-seconds - and I've added a timed Siren cut-off and automatic Reset. I've also replaced... [more]
August 3, 2010
This is a single zone alarm - with independently adjustable Exit, Entry and Siren Cut-Off timers. When the alarm is activated its Siren will sound once - for up to 20-minutes. Then it will switch... [more]
August 3, 2010
This Keypad is suitable for the Modular Burglar Alarm. However, it has other applications. Pressing a single key will energize the relay. Entering the Four-Digit code of your choice will de-energize it. [more]
August 3, 2010
This Keypad is suitable for the Modular Burglar Alarm. However, it has other applications. Entering the First Four Digits of your chosen Five-Digit code - will energize the relay. Entering the Full Five-Digit code -... [more]
August 3, 2010
If you use a lamp with a motion sensor for outdoor lighting, the original electrical switch is actually no longer necessary. If you replace the switch with the circuit described here, an acoustical signal will... [more]
circuit from:http://www.extremecircuits.net/2010/05/bell-alarm.html
August 3, 2010
Protect your valuable laptop against theft using this miniature alarm generator. Fixed in-side the laptop case, it will sound a loud alarm when someone tries to take the laptop. This highly sensitive circuit uses a... [more]
circuit from:http://www.extremecircuits.net/2010/05/laptop-protector.html
August 3, 2010
This circuit, enclosed in a small plastic box, can be placed into a bag or handbag. A small magnet is placed close to the reed switch and connected to the hand or the clothes of... [more]
circuit from:http://www.extremecircuits.net/2009/07/mini-alarm.html
All posts