Frost Alarm
The thermistor used has a resistance of 15k at 25 degrees and 45k at 0 degrees Celsius. A suitable bead type thermistor can be found in the Maplin catalogue. Th...
Frost Alarm
The thermistor used has a resistance of 15k at 25 degrees and 45k at 0 degrees Celsius. A suitable bead type thermistor can be found in the Maplin catalogue. Th...
Single Zone CMOS Alarm
This circuit features automatic Exit/Entry delays, timed Bell Cut-off and System Reset. It has provision for normally open and normally closed switches and will...
Single Zone CMOS Alarm
This circuit features automatic Exit/Entry delays, timed Bell Cut-off and System Reset. It has provision for normally open and normally closed switches and will...
Car Alarm and Immobilizer
The alarm is "set" by opening Sw1. It can be any small 1-amp single-pole change-over switch - but for added security you could use a key-switch. Once Sw1 is ope...
Car Alarm and Immobilizer
The alarm is "set" by opening Sw1. It can be any small 1-amp single-pole change-over switch - but for added security you could use a key-switch. Once Sw1 is ope...
Motorcycle Alarm
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...
Motorcycle Alarm
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...
5 Zone Alarm Circuit
Each zone uses a normally closed contact. These can be micro switches or standard alarm contacts (usually reed switches). Zone 1 is a timed zone which must be u...
5 Zone Alarm Circuit
Each zone uses a normally closed contact. These can be micro switches or standard alarm contacts (usually reed switches). Zone 1 is a timed zone which must be u...
Enhanced 4 Digit Alarm Keypad
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 termin...
Enhanced 4 Digit Alarm Keypad
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 termin...
Alarm Power Supply
This Power Supply is suitable for the Modular Burglar Alarm. However, it has other applications. It is designed to provide an output of 12-volts, with a current...
Alarm Power Supply
This Power Supply is suitable for the Modular Burglar Alarm. However, it has other applications. It is designed to provide an output of 12-volts, with a current...
Infrared gate 2
This is an infrared gate with two sensors planned to use in the wall in the way behind a door. It can be applied in a toilet to keep track of that someone is in...
Remote Doorbell Warning Switch
This circuit will light a lamp at a remote location when the doorbell switch is pressed. This circuit should only be used with the solenoid type doorbells, the ...
Alarm Power Supply
This Power Supply is suitable for the Modular Burglar Alarm. However, it has other applications. It is designed to provide an output of 12-volts, with a current...
Motorcycle Alarm Number 2
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 wi...