Hello I am new to these forums, and am in the stages of designing a circuit for my school gcse electronics project. I am trying to make a safe alarm which is triggered by a passive infra-red sensor, or possibly a micro switch. But I would like this alarm to be fully automated for the owner, and so once they have calibrated when working hours are finished (eg 5pm) and when they start (eg 7am) the alarm will be activated. This alarm when triggered will then spray a fine mist of smart water on the user and the items stole aswell as a siren and flashing lights (astable).
So far I have discovered that a 555 timer will not be accurate enough as it will be loosing upto 15 minutes or more day. So, so far I have have investigated using a 4060 counter, and a 4040 ripple counter in conjunction with a quartz crystal. So I was just wondering if anyone could shed some light on the subject of how to make the timer circuit which can then be used in conjunction with an AND gate. Once of the inputs being the users key card to activate the alarm, the second being during the designated time period.
Anyway thanks for the help guys.... hope I you guys can because I am having problems. Also i would like to avoid using a PIC chip unless it is absolutely necissary.
So far I have discovered that a 555 timer will not be accurate enough as it will be loosing upto 15 minutes or more day. So, so far I have have investigated using a 4060 counter, and a 4040 ripple counter in conjunction with a quartz crystal. So I was just wondering if anyone could shed some light on the subject of how to make the timer circuit which can then be used in conjunction with an AND gate. Once of the inputs being the users key card to activate the alarm, the second being during the designated time period.
Anyway thanks for the help guys.... hope I you guys can because I am having problems. Also i would like to avoid using a PIC chip unless it is absolutely necissary.