make an alarm system

[myp71]

Hello,
Is there any way to build a circuit that will alert me when my parking brake is set on my truck and when the engine is running I have the alarm I want to use but it is only single cell (1.5)volts off a old alarm clock so it needs to drop down the volts.Also the alarm would need to time out to 3-4 seconds then reset when either the brake goes off or the key is turned off.
P.s. if anyone can think of a better way to perform these actions then please let me know i'm open to any and all help<p>
thanks in advance
myp71
Ryan

[gadgeteer]

Aha! Someone's been driving with the parking brake on! Back when I was in high school, I was in the MARCHING BAND; one trip, a gas-station-attendant came running out to one of the school busses shouting, "HEY! Do you know you have FLAMES coming from under the BUS???" Driver had left the brake on...<p>(That wasn't NEARLY as funny as the trip where one bus pulled up back at school, one musician said: "Uhhh, 'scuse me, do you know your TIRES are grinding against the CURB?" Driver said, "Yeah, we... kinda don't have any brakes...")<p>THere's really no way of avoiding ADDING a switch on your emergency brake. I vote for scrapping the alarm clock, and tying the emergency brake switch into your "ignition-RUN" position, with an "AND" gate. There are several ways to do this without actually using an "AND-gate" --- you can make the EM-BRAKE switch CLOSE when the brake is OFF, and then ground the supply to that switch; take the SWITCHED lead, and tie it to the base of an NPN transistor. Base of that transistor also goes to "IGNITION-RUN" position (through an appropriate resistor --- sayyyy, 10k to 15k ohms). Emitter of the NPN goes to ground (we assume negative), collector goes to an inexpensive 12 volt beeper. When you turn on the ignition (to the RUN position), the transistor gets switched on; releasing the brake will GROUND the transistor base, switching it off. Providing you with:<p>BRAKE-ON + IGNITION-ON => BEEP!<p>(by configuring the EM-BRAKE switch to close when the brake is OFF, you have the luxury of knowing the em-brake is FULLY off...)

[myp71]

Really like the stories I almost choked on my dinner.Anyway thanks very much for your help I will see what I can blow up or at least make smoke come out of! <p>
Thanks again
Myp71
Ryan