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This circuit features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or a hidden switch; but it can also be wired to set itself automatically when you turn-off the ignition. By adding external relays you can immobilize the bike, flash the lights etc.... [read more]

This is a simple use of the PIC 16F84 about a diode tester.... [read more]

This circuit operates two LED strips in pulsing mode, i.e. one LED strip goes from off state, lights up gradually, then dims gradually, etc. while the other LED strip do the contrary.... [read more]

This circuit is intended to signal through a flashing LED, the exceeding of a fixed threshold in room noise, chosen from three fixed levels, namely 50, 70 & 85 dB. Two Op-amps provide the necessary circuit gain for sounds picked-up by a miniature electret microphone to drive a LED. With SW1 in the first position the circuit is off. Second, third and fourth positions power the circuit and set the input sensitivity threshold to 85, 70 & 50 dB respectively.... [read more]

The main requirement was to power the circuit by means of a common, PP3 (transistor radio) alkaline battery. So, implementing a low current drawing circuit was absolutely necessary, though preserving a High Quality performance.... [read more]

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 the LED with an entry Buzzer. These enhancements mean that the new version will have a much wider application.... [read more]