Okai, to make a push button remote start, where when the button is pushed the car is being cranked is pretty easy. And when the car turns over you just release the button.

I can make a delayed circuit, so that when you push the button it keeps cranking the car for X amount of time. But this wont work because the car would need different cranking times depending on the situation. And it could easily over crank the car and youll be with a nice new extra large paper weight.

My question is, how do remote ignition systems know when the car has turned over so that it can stop cranking the car?

Remote engine start kits have a Start/Stop Controller (SSC)

The SSC monitors engine speed with a flywheel sensor that signals each gear ring tooth. If engine cranking speed is too low, or engine running speed is too low, the engine will shutdown.

If the engine doesn't start after the programmable cranking time, the SSC enters a retry mode. After an intermission period, the SSC will again try to start the engine.

maybe it has a sensor that senses when the engine is at a certain rpm :confused:

EDIT: **** that was a good guess :D

Good luck making a flywheel sensor urself :D

i wouldnt know where to start

Ok this may sound crazy but what if you bought a remote central locking kit, but instead of rigging up the power wire to your door locks, rig it up to the starter motor or cranker or whatever starts the damn car :P. No idea if that would work but something to play around with :).

nahhh its more complex than that, need the right circuits and sensors and closed loop management systems to get it working and in order.

dude go to sleep and stop posting sleepy, half baked ideas :P

nahhh its more complex than that, need the right circuits and sensors and closed loop management systems to get it working and in order.

dude go to sleep and stop posting sleepy, half baked ideas :P
But on older cars you could do that right? i thought you could steal a car just by connecting up the permanent 12v to the starter motor?

Yes thats right, but when u connect the 2 wires together you need to know exactly how long to keep them connected until the engine starts then disconnect them once it has. Or else the starter motor is gonna keep going and burn out.

Thats why youd need the sensors to tell the system to stop cranking the motor.

Hence the point of Ascension starting this whole thread :rant:

:P

Yeh true, but you could use the button to start the car, and it would only send power as long as the remote button was pressed, so as soon as you hear ur car start than you let go. Though i can see where this will get confusing if it'ss raining or something you may not hear your car start. Also how would lights and **** work if you didn't have the key in the ignition?

Your a nutter !!
you asked:

what if you bought a remote central locking kit

So i answered ur question assuming u wanted to use a remote to start ur engine.. :rant:


If u just want a button, all u need to do is disconnect the wires and add a push button..
Youd still need the car in Accessories for it to start tho..

If I were to design a circuit to do this I would do the following.

Have an RF switch controlling the standard start circuit via a 12 volt relay.
Upon pressing the remote switch the circuit would 'latch on' and remain
on until such time as a couple of situations have been sensed
Some thought would have to be put into this stage as I would personally
design some failsafe, and safety type stages.

On first thoughts it might be possible to add a frequency counter type circuit to
sense the rise in RPM and switch it off when I reaches the point where the engine
has fired on it own. (would have to work this one out).
It would also need to be prevented from operating from that point on until the engine
has stopped (unless you enjoy changing starter motors regularly :D ).

I can see some benefits to having a device of the nature, but I too have concerns. If this were operating by a standard simple button like a remote alarm, what is stopping it being accidentally set off (accidentally pressing, or maybe deliberate pressing by the nearest 2 year old.)

Designing something like this wouldn't be as simple as first thought, but it can be done.

I can see some benefits to having a device of the nature, but I too have concerns. If this were operating by a standard simple button like a remote alarm, what is stopping it being accidentally set off (accidentally pressing, or maybe deliberate pressing by the nearest 2 year old.)
Designing something like this wouldn't be as simple as first thought, but it can be done.
If your going to go with a remote central locking type remote, you could get a 3 button remote and wire it so that you need to hit a sequence of buttons before if will let you start the car.
I have seen the same thing done for a car alarm. so that as well as the normal car protection, if someone steals you keys they need to hit a combo of buttons before it will let them open the car

ok lol sorry.
What about hooking up a sensor to the rev cable and when it detects a signal it stops cranking (as there would no signal when the car aint on). Sure you might over crank .1 of a second but hey, dont we all do that with the key sometimes anyway?

You could always time the average time you turn the ignition before you let go and it runs. The switch could just run for that set time. (A second or two of the starter motor running extra is not going to hurt it).

You could very easily construct a circuit to do this.

I just think there are too many problems that overshadow the reason why you would want it.

You would definately want a way to prevent accidentally setting it off. Not doing this could prove a lethal combination. I sure as hell wouldnt want to stick my hand in the engine bay with something that was prone to accidentally tripping and setting the engine going.

Okai, well ive been talking to some other guys on another forum and i think i found the answer.

When the car cranks over, the alternator starts.

So how do you tell your circuit to stop cranking the car? when the bat voltage goes above say 13V

Easy, you hot wire your car making a push button start. Wire this up so that when you press a button, it closes the circuit hot wiring your car automatically. Now this would crank for ever destroying your car, but your circuit is hooked up to the bat, and when the car turns over, alternator kicks in, voltage goes up, circuit sense this rise in voltage and cuts the relay which is cranking the car. Im guesssing this should work... only one way to find out!

What about an optical sensor on the flywheel. You'd have it shining through the teeth, or drill appropriate holes in the flywheel (lighten it!) and when the frequency passes a trigger point, it terminates cranking

It's an idea, but I don't know if it's feasable. (I would use a 555 or something similar to count)

HA done this before, not to the magna but the ride On mower :badgrin: it was chalenging but the old car alarm i had had a boot release button which i used to trigger a relay to start it and once it started to generate voltage for charging it disconnected the relayvia a second relay :confused: but it worked except it didn't have a neutral switch so it would still start in gear :bowrofl: :bowrofl:

Just a couple of things,
Starter motors have an over run clutch which allows for when the car starts, the flywheel speed exceeds the cranking speed of the starter and the clutch slips preventing the starter from over revving.

What happens if it stays engaged with the engine running and you drive off , the windings on the rotor get forced out and chomped up due to centrifugal force . :shock: I have seen the results not pretty.