555 timers

[kraverauk]

Hello, I am an electronics student at college and i am creating an alarm system for my car. I want the alarm to run for 10 minutes but i am unsure how to create a 555 timer circuit that makes the alarm run for 10 minutes? I have created a few test circuits using the 555 timer with a battery, two resistors, a capacitor and an LED to get the LED to run for a certain amount of time but i can only to get it to blink and not stay on for a set amount of time, can someone please give me advice ?

[KMoffett]

You could try this monostable 555 circuit: http://www.technologystudent.com/elec1/5554.htm. C1=470uF and R2=1MΩ will give you ~517 seconds. Use a CMOS 555.

Ken