Notifier for diff locker off

[Niva867]

Hi. Back when I was 12 - 15 years old I was interested in elecronics. Then my interests shifted towards software programming.

Right now I have a 4x4 with mechanical transmission, locker, and hi-low selector.

http://www.google.ru/search?um=1&hl...urce=og&sa=N&tab=wi&ei=-y9KT_rHKsjptQaClamUBQ

During offroading extremes, locker has a tendency to turn off. Not once I found myself in mud with locker off. Problem is usually I don't keep my attention on locker, and end up spending a lot of effort getting myself out of bad situations.

I need a circuit board which will notify me via sound and blinking led when locker is turned off. There is a 12V light bulb in the car, which is on when locker is engaged, and off when it is disengaged. It be nice to have a sound notification when this light bulb is turned off, plus a blinking led up in driver's face.

Can you help?

 

[Harald Kapp]

To get sound, you can simply connect a 12 V buzzer (e.g. here: http://www.buzzersdirect.com/) across the indicator lamp. Add a simple switch in series with the buzzer so it won't annoy you while the locker is intentionally off.

For the alarm light you could use a blinking LED (e.g. here http://ledz.com/?p=leds.blinking) with a suitable series resistor (approx. (12 V - 2.5 V)/20 mA) = 475 Ohm.
Put this circuit parallel to the buzzer.

Regards, Harald

 

[duke37]

Harald,

I think he needs it the other way round, i.e. the circuits should activate when the light is out.

I think a changeover relay with the coil connected across the bulb would do, using the back contact.

Duke

 

[Niva867]

Yea, need the sound to come when the light is off. It be nice if the sound turns off automatically, beeps a couple times, and then off to sleep. Please draw a diagram. Thank you!

 

[Harald Kapp]

Duke, you'r right, I didn't get that in the first place.

A changeover relay or a normally closed relay would do part one of the job.
For the second part, turning the alarm off after a few seconds, a timer would be needed. A timer as is used for the interior lights of the car could be used for that.

Harald