Start / Stop button.

[Dave Eastwood (Gadgetman) - Club Chairman]

very idea Mr Blue  like this, I guess smartkey and latching relay like this . I've not come across those before - its a dip/main beam relay - could have loads of uses..

I think £4.34 should do mine  ...    fleebay

 idea indeed, the security sides the one thing that's put me off having ago.

Not really bothered about the full control system approach, on an aeroscreened car I don't have enough to control   though interested in the technology, as the Motec and similar style systems are sort of the automotive euivalent of the stuff I deal with for a living.

[Blacknblue]

The RF ID relay is basically a starter relay with a coded key fob, if the fob is within range of the relay it functions as normal. Otherwise it does nothing.

They're sold for motorcycles really as an immobiliser, it's meant to replace the standard starter relay.

I'll knock up a basic diagram tomorrow if i get a chance.

[Blacknblue]

very idea Mr Blue  like this, I guess smartkey and latching relay like this . I've not come across those before - its a dip/main beam relay - could have loads of uses..

I think £4.34 should do mine  ...    fleebay

Yes that's the RFID one, I added the 2 second delay relay in to crank the starter

The £4.34 one off ebay is a standard relay, not latching, so it needs current all the time to maintain it. The latching one cycles from on to off each time it receives power. So first press of the switch it latches to on, second time it latches off.

[Mat Jackson]

Blacknblue, that sounds like a great solution!!

Have you just got the two relays in parallel?  If so what happens if the ignition is on and then you press the button for two seconds?  I presume the starter cranks but the engine will not fire as the ignition will be off?

I guess I am thinking of a way to ensure the ignition is on before the starter will crank - a double switch really would do this I think?  Use a double switch latch relay on the ignition circuit, one switch to the ignition and one in series with the two seond delay relay.  That way the switch would need to be depressed for 2 seconds, and the ignition would need to be on for it to start!

[Tango Squadon]

Really interested in building something like this myself.  Cannot find a delay relay (or perhaps understand what it is ).

Do I have to attached a simple timer circuit to the side of a normal relay or is it a special relay with some sort of delay armature motion on coil energisation?

[Martin Keene]

I don't get the fad of starter buttons. The misses has got one in her S2000 and it annoys the pants off me... Especially if you stall it, you automatically go for the key.

[Blacknblue]

Delay relay here

Latching relay here

As for stalling etc, don't use the key, only the start button so natural thing is to go for the button anyway.

But I do know what you mean, one of our cars is a Range Rover with the ignition key in the centre console, the number of times I go for the side of the column to find it's not there is annoying.

[Tango Squadon]

Please can you help me with how to wire up this relay.  Sorry, limited electronics skills!  

Here is a diagram of the delay relay.

Do I connect an earth to 31 and 12volts supply to 30.  This will output 12v on 87a and nothing on 87.

If I then apply 12v to 15, there is a 2 second delay and then 12v switches from 87a to 87 for as long as 15 is held at 12volts?

[Blacknblue]

Do I connect an earth to 31 and 12volts supply to 30.  This will output 12v on 87a and nothing on 87.

If I then apply 12v to 15, there is a 2 second delay and then 12v switches from 87a to 87 for as long as 15 is held at 12volts?

Yes that's how I've done it.

When you order the relay if it's from a Durite stockist they're usually done to special order as the time delay is set to whatever you decide. 2 secs seems fine to me and works ok

[DerekJ]

I like the ideas   but have one reservation regarding the start/stop button.

What happens if, once the engine has started, the button or wiring fails? How do you turn off the engine? This system is relying on a positive stop signal not a contact break.  I suppose the back stop would be the battery isolator but that's not ideal.

Cheers

DerekJ

[Blacknblue]

I guess if it really worried you that the button or wiring is likely to fail then add an emergency switch perhaps behind the dash out of the way. If it's in the output of the latching relay. That would simply disconnect the ignition until you resolved the fault.

Have to say most simple push to make switches are just that quite simple and in this mode not carrying much in the way of current so unlikely to fail, but yes you're right it is possible for the system to fail in the on mode.

[Mat Jackson]

How have you wired your steering lock in?  Or have you removed that.  Though about wiring it to the immobiliser, but if that failed whilst driving the lock could latch on...

[Tango Squadon]

OK, I need help again!  Here's a diagram of the latching relay circuit.  

Apply 12volts to 56 and 56b is at 12v.  When relay is latched then 12v switches to 56a.  I guess the relay has a mechanical latch. When the coil is momentarily energised the contacts operate and 'latch' in that position. To unlatch the contacts the coil is momentarily energised again.

So do I earth 'S' and apply 12v to 30 to latch.  Applying 12 to 30 again unlatches (ie switch back to 56b).  Have I got these the right way around  (i.e. should 30 be earthed, 'S' get the 12v)?  Looks like there's a diode in there to protect it (?).

Not sure if unit is faulty or it's me that's faulty.  Can anyone help?