_jklumpp_
Posted 07 May 2013 - 07:54 PM
I've just bought a piezo buzzer to connect with my oil warning light, but I'd prefer if it didn't go off every time I turned the ignition on.
Does anyone have any thoughts on a way to have it only come on if the engine is running, or maybe a timer so that it doesn't come on in say the first 30 seconds?
_hutch_
Posted 07 May 2013 - 08:25 PM
You could power the buzzer from the exciter circuit in your alternator so it wont operate until the alt starts to charge,you would also need to fit a blocking diode in it as well,of course this will also depend on how early the alt starts to charge as well
Phillip
_434LX_
Posted 07 May 2013 - 09:05 PM
Having the buzzer go off when you start is a good thing. Lets you know its working.
You can always put a push button switch in the buzzer circuit to "mute" it
_oldjohnno_
Posted 07 May 2013 - 09:08 PM
A tachometric relay would be a cheap and simple fix. An auto sparky or anyone who works with LPG engines or forklifts would be able to supply one.
.
Posted 07 May 2013 - 09:33 PM
Having the buzzer go off when you start is a good thing. Lets you know its working.
You can always put a push button switch in the buzzer circuit to "mute" it
i like that idea,now wheres a boffin to explain how to do it??
.
Posted 07 May 2013 - 09:57 PM
i guess you could just use a push button on/off to turn it off after putting the ignition on and hearing the buzz. not much use if you forget to turn it on again though after starting.
would there be some way to silence it after it goes off, without actually turning it of. kind of acknowledging the alarm?
_434LX_
Posted 07 May 2013 - 10:04 PM
A basic timing circuit using a 555 timer ic (google it) controlling a small normally closed relay.
Ignition on, alarm sounds. Hit the push button and the relay cuts the circuit for x amount of time. (aka - stop buzzing at me !)
By the time the relay cuts back in, you'll have oil pressure and peace and quiet.
If that really floats your boat, i'm sure I could knock something up for bugger all.
.
Posted 07 May 2013 - 10:17 PM
cheers Andrew, thats why we let the nerds hang around 
off to google black magic, smoke and mirrors and electrickery
CABIN ENGINE CONTROLS GALORE
Posted 07 May 2013 - 10:53 PM
Hi All,
Have a momentary 'OFF' push button ( rated to the power usage and is spring return ) switch in the power cable to the buzzer, and then press it down when the buzzer sounds ( which will Mute it ), when you take your hand away, the button automatically releases ( Spring return ) and the power to the Buzzer circuity returns to normal. Dave I
Edited by TORYPOWER, 07 May 2013 - 11:01 PM.
_Gunmetal LH_
Posted 07 May 2013 - 11:38 PM
A fade on circuit switching a transistor?
Basically a capacitor and resistor have to build up charge before turning on/switching a transistor which can be put inline with the buzzer power.
Would give you a delay for startup/ignition on, but work normally after the delay time so the buzzer goes off straight away when turned on after that.
Jaycar would be the place to get all the bits.
Fulcrum Fixture
Posted 08 May 2013 - 09:22 AM
Having the buzzer go off when you start is a good thing. Lets you know its working.
I like this idea.
If you don't like a buzzer you could always use an idiot light as per OEM.
_jklumpp_
Posted 12 May 2013 - 09:07 PM
Thanks Andrew, that sounds like the sort if thing I had in mind.A basic timing circuit using a 555 timer ic (google it) controlling a small normally closed relay.
Ignition on, alarm sounds. Hit the push button and the relay cuts the circuit for x amount of time. (aka - stop buzzing at me !)
By the time the relay cuts back in, you'll have oil pressure and peace and quiet.
If that really floats your boat, i'm sure I could knock something up for bugger all.
_434LX_
Posted 12 May 2013 - 11:51 PM
Should be a cheap experiment to have a crack at.
You could use prototype circuit board http://www.ebay.com....=item3ccb60a3d9
As a basic start you could try this layout :
C1 10uf 16V Electrolytic Capacitor
C2 0.01uf Ceramic Disc Capacitor
R1 1 Meg Pot (This allows time adjustment )
R2 10 K 1/4 Watt Resistor
D1,D2 1N914 Diodes
U1 555 Timer IC
Use a 9 volt relay like this -> http://www.ebay.com....=item2325f73c64
_434LX_
Posted 12 May 2013 - 11:55 PM
Oh, and the relay should be a normally closed type (9 volt coil trigger voltage).
You just want to break the buzzer circuit for x time when you push the button.
_434LX_
Posted 13 May 2013 - 12:02 AM
Now that I think about it, you could even save a bit of hassle with :
http://www.ebay.com....=item4172034ac5
or
http://www.ebay.com....=item460acc793e
hahaha 
_Gunmetal LH_
Posted 13 May 2013 - 07:24 PM
Would those delay every time though? You wouldn't want a 30sec delay of the buzzer if there's a problem.
_jklumpp_
Posted 13 May 2013 - 09:11 PM
Andrews comments made me remember an article I read in AutoSpeed a while a go, so I looked it up and found it http://www.autospeed...51/article.html
A quick look on Ebay found thishttp://www.ebay.com....=item33816e834d
The idea peter is that it's setup as a 'Normally Closed' circuit - so the buzzer will operate normally UNLESS you press the button on the timer, which will deactivate it for the preset period of time.
.
Posted 13 May 2013 - 09:37 PM
cheers for the link, just ordered one of those delay timer relay whatchits..
_jklumpp_
Posted 14 May 2013 - 08:46 AM
yeah, I put in an offer of $8, and it got accepted, so it's on it's way to my door for $10!
Yes, yes I do post alot!
Posted 15 May 2013 - 10:43 AM
_jklumpp_
Posted 15 May 2013 - 11:31 AM
no, you're not Chris... but they're a normally open circuit, that closes for a pre-set time - what we need is the reverse.... not to mention how big, bulky & ugly they are! :-D
.
Posted 23 May 2013 - 02:02 PM
.
Posted 23 May 2013 - 04:45 PM
still waiting for the buzzer thingy.... any electrical nerds, what do i do with the relay thingy?? does it have to go in some kind of casing?
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