I am by no means an amateur when it comes to the Fiero Electrical System, and I have done numerous security, remote start, and keyless entry systems on Fieros AND other cars.

The dilemma I have is entirely in the "How to" on a circuit I am thinking up.

Push button start. I know how it works, I know how to retrofit it into a vehicle, and I know how to wire one into a Fiero and retain the stock key function with the push button addition...

My Dilemma lies in the desire to lose the column key entirely. Putting all security concerns aside in this case, I want to draw up a basic plan of attack for the system I have in mind.

There are three options in the future for this.

Option 1: Retain the key functionality. Do this by utilizing either a Motorcycle based On/Off key barrel that will allow two directions of movement from the at-rest position or a GM Dash mount key system from a 2000+ Olds/Chevy/whatever. Disabling the steering column lock has already been figured out in my mind.

Insert key at rest. Turn key to right to turn on electrical systems such as Fuel Pump and basics. Then use push button to start the vehicle and engage all other electrical systems. To shut system off, turn key backwards to shut off all electrical systems. Then remove key.

Option 2: Use three position momentary contact switch. At rest is in middle. Identical to key from Option 1 except that switch ALWAYS returns to at-rest position when released. Turn switch to right. This engages a latched relay or circuit which would turn power on to fuel pump and basic systems. Power stays engaged even when switch returns to at-rest. Push button to start vehicle and power all remaining systems.
To shut off, turn switch to left. This would release the latched relay shutting all power off to all systems. Switch returns to at-rest.

Option 3: (Desired option) Push button which simultaneously starts vehicle and powers all circuits. To shut off, push button again which shuts power off to all circuits.
Needless to say, this last option would be more complicated wiring wise, as you would have to design and install a starter disengagement switch that would not allow the button to engage the starter again while there is power to the circuitry. That seems simple enough, as you would have to simply wire in a relay that OPENS the circuit while voltage is applied to the relay. This would have to be delayed of course, because by pressing the button you would disengage the starter circuit before starting the vehicle.


Options 1 and 2 would be the simplest. You run the primary power from the Ignition harness through a high amperage relay. You use the switch to engage the relay to turn the circuits on. Powering the accessory and Ignition 1 and Ignition 2 circuits is easy from this setup.

Option 1 would utilize a standard automotive relay for high amperage. This relay would stay engaged as long as the key was on. This would then provide power to all circuits, including the push button for starting the car. Shut the key off, the relay shuts off, and the power to the vehicle shuts off. Simple enough.

Option 2 would utilize a latched relay mechanism. Turn switch to the right. Relay engages and powers circuits. Release switch which returns to at-rest. Latched relay maintains power to all circuits, including the push button starter. Turn switch to left, latched relay then flips to other pole, which has no connection. This would remove all power from the circuits.

Option 3 would utilize a latched type relay as well (In my mind anyway). Power is provided to the relay input at all times. Pressing the start button latches the relay which provides power to all circuits. The starter also engages as long as the button is held down. Releasing the button does not remove power from the circuit but it does disengage the starter solenoid. Subsequent presses of the button while the vehicle is running will result in loss of power to the circuit by disengaging the latched relay. The starter will NOT re-engage on the second button press.

Am I making any sense?

Option 3 is what I want. I am working on an RFID type system to recognize me without a key, so the security is not in question here.

Any input on this? Help with designing the circuit?

I was about to mention the RFID option when I read the last part of your post. This would be identical to the system in the new Nissans. Just keep the RFID tag in your pocket (or purse) and push the button to start the car. Push it again to turn off the engine. You can also incorporate this into the electric door locks to unlock the doors if you push a button on the door handle.

I would buy a system like that and throw away the ignitioin key.

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I have been entertaining similar thoughts on a starter button.

On the circuit for option 3:
I have somewhere in my piles of stuff, what may be the perfect relay for this task. A momentary switch feeds current to a coil that moves the relay to it’s the opposite throw previously held. Each application of momentary power reverses the throw of the relay and it is held there mechanically until the next momentary pulse is received. In turn, its throws act on a double pole double throw switch. I have not seen it in a few years and don’t remember shat the voltage range of the activating coil is.
If one were to use a momentary double pole switch to activate it and the starter, one would be wise to include a circuit to disengage the power to the relay coil after it throws because feeding it continuous power while you crank the starter would shorten that coil’s life considerably.
Baring such a relay, all of this seems doable using a bunch of reed type relays available from Radio Shack. I like these relays because they are completely sealed and have no moving parts other than the deflecting reed. I don’t have a grip for their longevity when energized continuously though. They are a no brainer when compared with designing a solid state circuit too.
If I understand correctly, option 3 would still require inserting the key to unlock the steering column right? I know nothing of the dash mount key systems of which you wrote. I guess you are thinking of just leaving the key in the column unless you are parking in an unfriendly environment. I don’t think I quite have it.
I have been thinking along the lines of Option 1 with the starter button located where the rear defogger button would be if I had one.
I don’t think accidental starter activation would be much of a concern with the switch there.
Upscale modern circuitry controls starter shut off and everything. I don’t think we want to go there.
I had a 1960 Austin Healey 3000 years ago with a starter button along side of the keyed ignition switch. I liked it because you’d switch on the ignition and listen for the fuel pump to stop before hitting the starter button. This saved unnecessarily cranking the starter while the fuel pressure was still coming up.

I am planning on doing away with the key entirely, and using a cable mechanism with a solenoid to unlock the column when the circuit is engaged.

A latching relay is what you are thinking of. It uses a cam/lever system to lock the relay in the position it is in. If push comes to shove though, you can use a latching relay to provide a low amperage lead to a bank of relays for the various circuits. That would actually not be that difficult to do. It adds some complication to the system, but would provide easy diagnosis and replacement as well as isolation of each circuit, the Accessory, Ignition 1 and Ignition 2 circuits.

I can draw up a schematic later tonight possibly.

I've been thinking about doing this for a while now but I was just going to use the simple JC Whitney $40 kit where you still have to turn the key to ON then push the button.



heres mine (not in the fiero) the systems safety fallback is you have to depress the brake to make the car start

quote Originally posted by Mr.PBody: I've been thinking about doing this for a while now but I was just going to use the simple JC Whitney $40 kit where you still have to turn the key to ON then push the button. heres mine (not in the fiero) the systems safety fallback is you have to depress the brake to make the car start

Yup. My system would be going into a Manual vehicle, and would maintain the "Press clutch" safety feature. An Auto vehicle would have the brake safety if I was installing in there.

I have been thinking about the keyless set-up as well. A friend of mine, that works for a Caddy dealership is bringing me, the wiring diagram to a XLR caddy. This system has the keyless system in it. You just walk up to the car, it unlocks the driver door and arms the ignition. You get in and push the start button. This system also detects when you are at the trunk and opens it for you. I have a salvage yard near me, that has six of these Caddys. As soon as I get the wiring diagrams, I will know what parts to pull from the XLR.

Don Z.

what about a 2 stage push button?
where
1st bit of depression of the button gets all the necessary electricals running..
2nd & furtherst bit of dperession starts the car and when pressure is unapplied the button reverts to the 1st depression setting

this would be very similar to when you start your car now and the power all shuts off as the car is being started and then once started the electricals all runs as the would any other time..

just my $0.02

Ryan

A $2 microcontroller (Atmel Tiny11 or Tiny15, 8 pin DIP), ULN2003 relay driver chip and some relays is all it would take... That and the programming for the chip. Then your push-button can be a simple "normal" one that handles no high-current. Add other optional inputs (larger microcontroller with more pins) to allow say your alarm remote to start the car. Not volunteering (yet) to build it, just an option. Maybe when I'm done with the time-absorbing projects I've already gotten myself into over my head..

quote Originally posted by CheshireGrin: what about a 2 stage push button? where 1st bit of depression of the button gets all the necessary electricals running.. 2nd & furtherst bit of dperession starts the car and when pressure is unapplied the button reverts to the 1st depression setting this would be very similar to when you start your car now and the power all shuts off as the car is being started and then once started the electricals all runs as the would any other time.. just my $0.02 Ryan

Thats exactly what my car does (well close to). Hop in put in the key and click the START button and the gauges come on and the a/c and heat will work. Put your foot on the brake and push START again and the engine fires up. My car is an auto btw.

Well, I got the schematics. This is the main one. As you can see the system is a stand alone unit.



This looks a bit better. 05 Caddy XLR PIP will only let me show it at a small size. If you want a copy, just let me know.

[This message has been edited by 3.8 SC (edited 11-13-2007).]

The interesting part is, I found a micro-controller based system tonight for under 200 dollars. It is still in development, but has reached beta and production for the "Stage 2" kit which requires the Key to unlock the column and provide voltage. The "Stage 3" is RFID based and just requires that you set your key down in a location such as a cup holder.

I would love to build one myself, but do not have the capabilities to do it.

I wouldn't think $200 is *horribly* bad if it came with the RFID setup, but how much does that add? I tried looking at the schematics above, but I was getting a headache turning my head sideways that long. PBody: what car is that in? That thing looks really good there. Is that wood, or "fwood"? I like the grain..

No its REAL, its an 07 BMW with the premium pack and special order wood. Who am I kidding its the 328i, yeah its the base model...


o/t but heres a few more links to it
http://i149.photobucket.com...0Series/DSCN0687.jpg
http://i149.photobucket.com...0Series/DSCN0680.jpg
http://i149.photobucket.com...0Series/DSCN0681.jpg
http://i149.photobucket.com...0Series/DSCN0688.jpg

[This message has been edited by Mr.PBody (edited 11-13-2007).]

Base model or not, that's pretty damn sweet. Blows the doors off my "base model" tC. Mmmmm, cheap plastic.....