Software is required for a house burglar alarm system.
House Burglar Alarm Specification
A house has 4 rooms each of which have a PIR motion sensor. Each room has a security light. There is also a PIR sensor outside the front door, which becomes active when it is dark outside. There is a security light outside the front door. The security lights are switched on, and an audible alarm sounds under certain conditions.
If the outside PIR is triggered (i.e. it is dark, and motion is detected), an outside security light is switched on for 20 seconds. Any room sensor activated will trigger the light for (only) that room for 10 seconds.
Any two room sensors activated within 10 seconds will set off the audible alarm continuously. If after the outside sensor is triggered, a room sensor is triggered within 20 seconds, the audible alarm will sound continuously.
The only way to stop the audible alarm is to input a correct PIN. If the correct PIN is input, the alarm system is de-activated, and becomes dormant (ready for further burglar detections). If an incorrect PIN is entered, a ‘first warning’ is given on an LCD panel.
If a further incorrect code is entered, the alarm remains on, the outside light flashes, and a message is sent to the police station. Entering the correct code at any time that the audible alarm is on will de-activate the alarm.
Tasks. For the specification given:
1. Produce a State Event Action table (SEA)
2. Produce a State Transition Diagram (STD)
3. Produce a Structure Chart (SC)
4. Produce a Basic Program Structure (BPS)
5. {Produce a Flow Chart (FC)