laser motion detector starter

I first saw this on pimp my ride. basically its a laser motion detecter they wired in the pillar and to start the car all they had to do was wave your hand in front of it. i want to do something simular but i want it actually to have to be touched. what i have done so far (and i can provide schematic if necesary) is create a timer that is triggered by touch. I still want the key to be used but not be able to start the car. basically you touch a special trigger and it starts the timer which runs the starter. my problem is i cant figure out how to get it to stop when the car starts. i would have to utilize the rpm wire as feed back into the circuit to trigger the timer to stop trying to start once it has started. but thats where im stuck. if any one has any input i would greatly appreciate it.

here's my 2 cents. get yourself a remote starter. hack the rf input circuit and tie in a capacitive touch switch. the touch switch will replace the remote in theory.

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well that would defeat the purpose of doing this on my own and spending as little as possible on it.

eternal1 wrote:

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my problem is i cant figure out how to get it to stop when the car starts. .

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Not sure why you are using a Timer, unless you are Building your own R/S.
Most R/S's have aTimer built in

A few Remote Starts have a Trigger wire for Start & Stop which requires 250 - 500 ma Negative Input.  If you Touch Control will Start it, your Touch Control will Stop it.  Or have another touch for a Ground  to the Hood Pin Switch wire to Stop.

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MO

Don't Learn from Others Mistakes
You Might Be the One That Knows.

On pimp my ride, they used 791xv. They used an activitaion input wire for the remote start.
Waving his hand by provided the 2 pulse required to initiate the engine start.
read wat mo12v has to say. Hes right.

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Note: You Always Dont Get What You Pay For.

You'd have to be careful to make sure you design it so it doesn't trigger on its own.
Without something mechanical and being uncoded, it's going to be prone to false triggering, which is definitely undesirable in a remote start circuit. You'll have to put in all the usual RS safety interlocks for sure- might not be saving much over buying something, with the cost of the basic units being what they are.

well its not exactly going to be remote start. the way i would have it wired would be the key would have to be in the ignition and turned on for it to even work. im more or less just looking for something diffrent in the way the car is started. like what they did. mostly just for kicks.

Oh, that is a little different then---- you don't need it to automatically start the car and keep it running......... you just want a special, different way of cranking the starter to get the car to start, but only if you've already inserted the key and turned it on.

So it would be partially an anti-theft kill switch, and partially a cool trick........ but you have no desire for actual remote start, right?

They do sell pulse timers, so that you can set the timer to make an output for as long or as short as you want.

If you have a late-model, reliable, non-modified car and you can predict the cranking time, that would work out pretty well.....what kind of car is it?

If you have an older car, or a car that takes longer to start when it's cold as opposed to when it's warm, that's not going to work reliably.........

Here's another idea:

Install the touch sensor, and the pulse timer.......set the pulse timer to an extra-long setting like 1.5 or 2.0 seconds..........and also wire in a relay so that it can crank the car's starter ONLY when the brake lamps are on.

Instructions for you:

1. Enter car, turn ignition on, step on brake. (Car won't start at all without brake on---more anti-theft protection!)

2. Wave your hand across your special switch.

3. Starter will crank, and you would pull your foot off the brake as soon as the engine starts. If you forget and keep your foot on the brake, the starter will overcrank a little, but no so much it would hurt anything.

Also, this would help to prevent accidentally re-cranking the car after it is already running......you wouldn't want the starter to crank every time that sensor gets tripped.

ANOTHER IDEA:

I don't know how reliable a motion sensor would be, adjusted for close range like that.

But I've seen on Compustar units, they have a "knock sensor" to be installed on the windshield glass.......the idea is that if someone knocks on the glass, it'll page the car's owner (via the two-way remote) to return to the car.

Maybe you could find a used/cheap knock sensor somewhere, and modify it to suit your needs.

now thats a sweet idea i like that. i have a 2002 mitsu lancer and it is a standard so the only way it would crank is key in the ignition as well as the clutched pressed. but i like the brake idea the only problem with setting the time is its built into the circuit im building so it would be a matter of changing a few components to change the actual runtime. if someone can tell me how i can post the actual schematic of the circiut on here.

this is the basic design of the circuit. basically you trigger it and get a voltage output equal to the voltage input. in this case 12 volts. an explantion of the circuit can be found at https://www.kpsec.freeuk.com/555timer.htm
the one i have built is a monostable. a bit tuned down from theres but works.

Hey, that's a cool page. I put it in my favorite places, so I can look at it again later. I'm good with relays and switches and wires.....but I really need to expand my knowledge of the other stuff.

So it's a Mitsubishi Lancer, it's not very old, and I assume it's in good running order?

When installing remote starters in late-model Mitsubishis, I program my remote starter's cranking time for 0.8 seconds, which seems to work perfectly.

My co-workers leave the unit set at its default 1.0 seconds, resulting in a slight, but not objectionable, overcrank.

In both cases, customers have not come back with complaints, even in winter, so I assume that's a good cranking time for you to use too.

So anyway, I assume you know how to work that 555 timer........ are you able to set it for approximately .8 or 1 second of output? You could use that output to drive a relay, to trigger the car's starter wire........   does the 555 put out a negative or positive trigger? I can tell you how to wire up the relay if you want.

I assume your plan is to cut the car's factory starter wire in half, thus disabling the key from starting the car........... and then use your setup to drive the "engine side" of the wire you cut. Right?

Regardless of how you do this, I would strongly recommend a hidden toggle switch, to bridge the Mitsubishi's starter wire back together as factory whenever necessary. There are several reasons for this:

-If you return to the dealer for service, they won't be suspicious you've modified anything.

-Valet parking attendants, car wash people, family members, friends, etcetera, can drive the car without confusion.

-If any of your system fails (and it's experimental, so you should be prepared for occasional failure), you'll have a backup.

-If it's incredibly cold, or your car falls out of tune, you'll be able to crank the starter for as long as you need to, rather than being constrained by the output from the timer.

you are correct on all accounts. the timer puts out a positive voltage equivilent to the power source which in this case would be 12v+ the only limitation to time with this circuit is the resister and capacitor that you use on it. thats how the time is actually adjusted. the trigger can be source (just the touch of your finger on a bare wire will trigger it). its actually a really neat little circuit that can have many uses. and if you look at that webpage there are a few diffrent types of that circiut. the 555 timer can be found at any component shop and radio shack still sells them as well. anyways thanks for all your input and help im sure i will come up with something shortly and i will let you know when i do.

ok how about this. timer circuit powers a relay at say 10 volts, 12 volt rpm wire also feeds into the other side of relay. so circuit powers up and kicks relay on, when moter starts the 12 volt rpm wire goes hot and powers the relay into the other direction killing power to the starter. since the rpm wire will have the higher voltage it would over power the circuit power right? would that work or not?

Hmm, that's an interesting question; I don't know.

I am not sure how the Mitsubishi's engine computer and instrument cluster work......you may (or may not) be able to access the tachometer signal behind the instrument cluster. I know it's available on a late-model Eclipse, so probably on your car too.

For the typical remote starter install, we often use a spark coil or fuel injector as our tachometer signal....

Basically, the coil or injector will usually have two wires. One receives power with ignition. The other wire.......the car's engine computer applies a ground when it wants spark (or fuel)......the ground goes away when spark or fuel is not desired.

Obviously, as the engine rotates, the spark plugs and fuel injectors are constantly, rapidly, being turned on and off.

If you were to put a test light on one of these wires, with the engine running, you would see the light flashing rapidly.......and flashing faster as you rev the engine.

I know that many remote starter installation manuals refer to these wires as AC, but I think a better description is that it's simply a DC ground, being switched on and off rapidly.

(By the way, even if you do get the direct tach signal that goes to the instrument cluster, it behaves pretty much the same way.)

I don't know how you could use that signal to command your relay to stop cranking the starter.

What is your ultimate goal? Simple and fast and easy......or are you interested in taking the long route, and learning stuff for fun, and trying to make it slick and smooth as humanly possible?

The reason I ask is because, if you just crank the starter for a fixed .8 seconds, I feel confident it's going to successfully start the car probably 49 times out of 50, and things will be fine.

It'll just be that once in a while when you've left the car sitting for a week, or you've picked up some minor mechanical problem you haven't had time to fix yet, or you've traveled to somewhere that's super-cold and the car sat all night.........it'll only be times like those when you'd need to flip your hidden switch, and start the car the regular way with the key.

If it didn't work reliably at that time setting, my co-workers and I would have seen a great deal of customers returning with complaints, and we haven't.

The way I've installed the remote starters is in voltage-sensing mode.....there's no tachometer signal....it just cranks the car's starter for the predetermined .8 seconds. If that wouldn't start the car reliably, the customers would be back in a matter of days.

i basically just want to do this to be diffrent along with learning something new. everything will be in a test situation first off with it not even being in the car. on the bench with a powersupply. the car sits for a week at a time anyways since i have a work supplied truck. so it only gets used on the weekends. but even then it starts right away with no problems. so i will play with the circuit and get it to the .8 seconds (or as close as possible) and put it in test situation first. if it succeeds the way i want it to then i will install it in the car and cross fingers that it works. but it seems this project will be put on hold for right now till some things around here settle down. i will take into account all that you have told me and i will post back once i get this done. thanks for all your help its greatly appreciated.