These are two - easy to build - relay-based alarms. You can use them to protect your motorcycle - but they have many more applications. If you use relays with 6-volt coils - they'll protect... [more]
This circuit will supply up to about 20ma at 12 volts. It uses capacitive reactance instead of resistance - so it doesn't generate very much heat. The circuit was designed to provide a cheap, compact... [more]
This is a universal four-digit keypad-operated switch - with a difference. Instead of entering the security code one number at a time - the four keypad buttons must be pressed simultaneously. Split the code between... [more]