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Radio Wave Alarm
Description:
This simple circuit is sure to have the police beating a path to your door- however, it has the added advantage of alerting you to their presence even before their footsteps fall on the doormat. More >
Car Parking Light Switch
Description
This is a simple parking light switch. The idea is that you drive your car towards your garage. You shine your headlights at the sensor, which switches on an external light . If you don’t have a garage the sensor can be placed on a wall or post, and the external light will illuminate the area while you park and leave your vehicle. The circuit also has manual on and off controls. More >
Electronic Doorbell with Counter
Description
This circuit uses a synthesized sound chip from Holtek, the HT-2811. This reproduces the sound of a “ding-dong” chiming doorbell. Additionally, the circuit includes a CMOS 4026 counter display driver IC to count your visitors. More >
Electronic Door Release
Description
The IC is a quad 2 input “AND” gate, a CMOS 4081. These gates only produce a HIGH output, when BOTH the inputs are HIGH. When the key wired to ‘E’ is pressed, current through R1 and D1 switchs Q5 on.The relay energises; and Q5 is ‘latched on’ by R8. Thus, the Alarm is set by pressing a single key,say one of the two non-numeric symbols. More >
Dark Activated Switch
This circuit will activate a relay when light falls to a preset level. Light level can be adjusted with VR1 and the relay contacts may be used to operate an external light or buzzer. More >
Frost Alarm activated switch
A simple thermistor triggered switch with adjustable threshold. It triggers with cold temperatures so may be used as a frost alarm or cold temperature switch. More >
Relay Driver circuit
One of the serious problems in relay operated circuits is the relay clicking or chattering during the on/off of the relay driver transistor. This problem is severe if the input circuit is a light / temperature sensor. During the transition of light / temperature levels, the relay clicks which may cause sparking of contacts. By using a simple tip, this problem can be avoided. More >
Micro-GT servo motor driver
Hi guys, this is a project from Italy, sent by Marco Gottardo. It is about the Micro-GT servo motor driver (or controller) and it is described as the best robotics power and economic solution, perfect like 14 servomotor driver. Now lets go through this project. More >
Light sensor switch circuit
This light sensor switch circuit allows the automatic connection of a lamp when the light is low (at nightfall) and will maintain the lamp ON for a certain period of time. More >
Touch light dimmer circuit
With IC SLB0586A from Siemens you can build a simple touch light dimmer circuit that will allow you to adjust the lamp intensity. Together with a TIC206D triac, it enables smooth regulation of light intensity from a bulb of 10W – 400W. A coil of 100µH/5A is required to suppress switching noise. More >