Engineering Projects

• Water-level Indicator

Simple, two-wire, remote monitoring unit
Three-LED level display, 9V battery powered

• Water-level Alert

Beeper or flashing LED alert
1.5V battery powered portable unit

• Temperature-controlled 12V dc Fan

Suitable for computer cooling fans
LED motor speed indicator

• 120 and 240Vac LED Voltage Indicator

Useful for power lines control
Simple, transformerless circuitry

• IR Remote-Control Checker

Suitable for any Infra-red emitting device
3V battery supply

• Water Pump Relay Control
  Water reservoir automatic level control
  Simple circuitry - 12V supply

• 230Vac Lamp Toggle Switch
  

Compact, transformerless circuitry
No relays employed

• Fridge door Alarm (2nd Version)

Alternative version of the popular circuit
3V battery supply - Still operating at 1.3V

• Emergency Light & Alarm
  
  Powered by two AA NI-CD batteries
  Four switchable options
  

• Clap Relay
  Clap sensitive on-off Relay
  3V Battery operated, small portable unit
  

• Bidirectional Photoelectric System
  Detects and counts inputs and outputs
  Suited to control Lamps, Household Appliances etc.
  

• Courtesy Light
  15 seconds delayed switch-off
  A good idea for bedroom lamp
  

• Door Alarm
  Hangs up on the door-handle
  Beeps when someone touches the door-handle from outside
  

• Bedside Lamp Timer
  30 minutes operation
  Blinking LED signals 6 last minutes before turn-off
  

• Timed Beeper
  Beeps 7.5 seconds after a preset time
  Adjustable time settings: 15 s. 30 s. 1 min. 2 min. & others
  

• Temperature-controlled Fan
  Gradually increases speed as temperature increases
  Widely adjustable temperature rang
  

• Self-powered Door-bell Watcher
  Detects if the door-bell has rung in your absence
  Also suitable for different electric appliances
  

• Dark-activated 230V Lamp
  Compact circuitry using small-size parts only
  Can be wired in parallel to existing switches
  

• Energy Leak Detector
  High sensitivity, portable temperature comparator
  Detects draughts around doors, windows, etc.
  

• Broken Charger-connection Alert
  Detects if a device is not properly connected to its supply
  Suitable for battery chargers, portable appliance supplies etc.
  

• Ultra-simple Voltage Probe
  Detects 1.8 to 220 Volts DC or AC
  Minimum parts counting
  

• Digital Remote Thermometer
  Remote sensor sends data via mains supply
  Temperature range: 00.0 to 99.9 °C
  

• Self-powered Fast Battery-Tester
  Tests 1.5 to 15 Volt cells
  Two-LED display, no power supply required
  

• Room Noise Detector
  One LED monitors three levels: 50, 70 & 85 dB
  Useful to detect too noisy environments
  
  
• Battery-powered Night Lamp
  Ultra-low current drawing
  1.5V battery supply
  

• Infra-red Level Detector
  Useful for liquids level detection and proximity devices
  Up to 50 cm. range, optional relay operation
  

• Nocturnal Animals Whisker
  A low-rate flashing lamp drives away undesired visitors
  Automatic on-off operation
  

• Live-line Detector
  Detects the presence of a live mains conductor
  Minimum parts counting
  

• Heating System Thermostat
  Controlled by indoor and outdoor temperature
  Simple, high reliability design
  

• Mains Remote-Alert
  Beeper and/or LED remotely-operated via mains supply line
  Simple circuitry, easy to build unit
  
  
• Cellular Phone calling Detector
  Flashes a LED when detecting an incoming call
  Powered by one 1.5V cell
  

• AC Current Monitor
  Senses high current-flow into power cables
  No wire-cutting, three versions available
  

• Smart Trailing Socket
  Mains sockets switched automatically by a Control Socket
  Up to 1000W switched power
  

• Fridge door Alarm
  Beeps if you leave open the door over 20 seconds
  3V battery operation, simple circuitry
  

• Plant Watering Watcher
  A flashing LED signals the necessity to water a plant
  Very low current consumption - 3V powered circuit