Control GCSE ICT

Input / Output, Processing Inputs Devices Processing Output Devices Sensors – temperature , heat, sound, Humidity, acidity, moisture, light, movement, pressure etc Comparing data – between pre-defined set limits e.g. upper and lower limits Actuator – motor that could control a barrier Lights – e.g. warning lights Buzzers – audible output e.g. an alarm Robotic Arm – move a device to a different place Heaters, Water pumps, Speakers, LCDs etc

Control Feedback Loop Feedback Input Process Output Control Program Analogue to digital conversion Data such as pressure, light and temperature is analogue data. Computers can only work with digital data. An interface box or analogue to digital converter (ADC) is needed to convert the analogue data from the sensors into digital data the computer can process. Feedback - Where input from sensors is used to change output in a control program, then the output is fed back to modify the input.

Input / Output, Processing - Greenhouse Inputs & Feedback Processing Outputs Temperature Sensor – measures air temperature Feedback – turn on heater, open windows Air humidity sensor – measures air humidity Feedback – spray mist into the air too low, open windows too high Soil Moisture sensor – measures soil moisture Feedback – add water is too dry Light Sensor – measures light in greenhouse Feedback – close shades if light level too high, turn on artificial light if length of day too short Compare temperature of greenhouse of upper and lower limits and select appropriate controls Compare humidity of greenhouse of upper and lower limits and select appropriate controls Compare the soil moisture of greenhouse of upper and lower limits and select appropriate controls Compare the light levels in the greenhouse of upper and lower limits and select appropriate controls Heaters – to heat the air LCD – Control Panel Displays time, Current Temperature, Humidity, Light readings, set limits Lights to provide artificial light Motors/Actuators to open and close windows Water Pumps to spray water mist into the air

Control System Applications Central Heating Systems Burglar Alarms Automatic doors Traffic Control Systems Car Parking Systems Robotics