In environments like factories, power plants and transformers in electricity substations, controlling temperature to a safe value is important. Supervisory and control systems are...

LED-based moving-message displays are becoming popular for transmitting information to large groups of people quickly. These can be used indoors or outdoors. We can...

Access control forms a vital link in a security chain. Here we describe a secure digital access system using iButton that allows only authorised...

Here is a microcontroller based wireless equipment controller that can switch on or switch off up to four devices at a desired time interval...

Here we show how you can control a toy car through your PC’s serial port using a pair of ASK transmitter and receiver modules....

Closed-circuit television (CCTV) uses video cameras to transmit signals to specific monitors. It differs from broadcast television in that the signal is not openly...

Communication from or to a computer has become almost essential in our day-to-day lives. Though we can execute many programs within a computer itself,...

Counting the revolutions per minute (RPM) of motors—determining the motor speed— is essential in the field of industrial automation. It is useful especially for...

Light-emitting diodes (LEDs) produce a radically different type of lighting than what we are used to. Already in use in many architectural and commercial...

Many central air-conditioning systems (ACs) have the option for cooling and heating both. These have a fan for blowing hot or cold air drawn...