Circuit : Ron J Email : Description This is an enhanced 4 digit keypad which may be used with the Modular Alarm System. Notes The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 terminals will NOT do. The Alarm is set by pressing a...
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Circuit : Ron J Email : Description This is an enhanced 5 digit keypad which may be used with the Modular Alarm System Circuit Notes This switch will suit the Modular Burglar Alarm circuit. However, it also has other applications. The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals....
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Circuit : Ron J Email : Circuit Notes Any number of normally open switches may be used. Fit the mercury switches so that they close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its centre-stand. Use micro-switches to protect removable panels and the lids of panniers etc. While at least one switch remains closed,...
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Circuit : Andy Collinson Email : Description: A circuit that offers visual indication of fluid level in a vessel, with a switchable audible alarm. Example uses would be to monitor the level of water in a bath or cold storage tank. The Conductance of Fluids Conductance is the reciprocal of resistance. The conductance of fluids vary with temperature, volume and separation distance ofthe measurement...
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This circuit is intended for audio surveillance of an unattended area, examples being a back garden or open space. It can be used to listen for wildlife or just as an extra pair of ears. Notes Using a single cable such as speaker wire or doorbell cable, this circuit can be remotely positioned, for example, at the bottom of a garden or garage,...
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A multiple input combination loack using CMOS counter IC's. Flexibility and code change is allowed by changing output connections. Notes The circuit above above makes use of the CMOS 4017 decade counter IC. Each depression of a switch steps the output through 0 - 9. By coupling the output via an AND gate to the next IC, a predefined code has to be...
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The circuit below was developed to guard the fish pond. In this case to prevent that the pump sucks just air when the waterlevel get below the pump. When the waterfilters get saturated and dirty, the water level behind the filter gets to an unacceptable level. You can see this when the pump also produces airbubbles in the water. Because you are not...
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RF pad (doubles as serial-pad) combination-controlled, fully customizable radio frequency remote control 2 years operation from a 9V battery (8uA in standby) up to 16 keys in a 4 by 4 matrix, fully configurable key-bleep on every key three separate combinations, expandable full source code provided (GNU C vompiler for AVR) replaces remote controls based on MM53200, UM3750 and UM86409 433.92 MHz output...
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From a designer's perspective, there are no "good" or "bad" circuits. This article will show how to transform a "pirate" smart card (cheaply available almost everywhere nowadays , as consequence of digital TV piracy plague) into a legal and pacific electronic key application. Opposite to popular belief, most TV smartcards are not clones of the original and trusted ones. Instead, they often are minature versions of general purpose microcontrollers...
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Lie Detector The circuit diagram of the Lie Detector is shown above. It consists of three transistors (TR1 to TR3), a capacitor (C1), two lights or LEDs (L1 & L2), five resistors (R1 to R5), and a variable resistor (VR1). This circuit is based on the fact that a person's skin resistance changes when they sweat (sweating because they're lying). Dry skin has...
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Serial LCD Controller using Microchip PIC16F628
12V Battery Level Indicator For Car Batteries
Rain Alarm / Rain Detector
