Security Idea
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Joined: Apr 2003
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From: Camano Island, WA, USA
Security Idea
Ok, I need some help on this idea i have.
the idea is to gut a cigarett lighter of it's heating element and wire it up so you can't start the car unless you push in the cigarett lighter in.
this would go along with my car's alarm. also i'd also wire up a switch to switch between using it to start the car, and powering accessories.
would i wire it up in line with the starter wire? anybody know what color it is?
the idea is to gut a cigarett lighter of it's heating element and wire it up so you can't start the car unless you push in the cigarett lighter in.
this would go along with my car's alarm. also i'd also wire up a switch to switch between using it to start the car, and powering accessories.
would i wire it up in line with the starter wire? anybody know what color it is?
Junior Member
Joined: May 2003
Posts: 882
Likes: 1
From: Kennesaw, GA
check the audio/video/ security forum. they have a write-up on this. there is a special relay that is momentary. you can wire it to any switch the pulses a positive 12 volt charge when you press it. don't quote me though, do a search in that forum. its a great idea though. good luck
edit:
here you go, here are some links, i searched for you
https://honda-tech.com/zerothread?id=720731
https://honda-tech.com/zerothread?id=384077
https://honda-tech.com/zerothread?id=436525
Modified by brads94accord at 4:43 AM 3/3/2004
edit:
here you go, here are some links, i searched for you
https://honda-tech.com/zerothread?id=720731
https://honda-tech.com/zerothread?id=384077
https://honda-tech.com/zerothread?id=436525
Modified by brads94accord at 4:43 AM 3/3/2004
Thread Starter
Joined: Apr 2003
Posts: 885
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From: Camano Island, WA, USA
Re: (brads94accord)
oh, i already did the push button starter
this is kinda different, this is momentary in the fact that you need the cigarett lighter in to start the car. but it's only in so you can turn the key to start the car. if you don't push it in, you can turn the key all you want, but it wont start.
this is kinda different, this is momentary in the fact that you need the cigarett lighter in to start the car. but it's only in so you can turn the key to start the car. if you don't push it in, you can turn the key all you want, but it wont start.
Joined: Mar 2004
Posts: 81
Likes: 0
From: Great White North, canada
Re: Security Idea (DIYaccord)
What you need is some kind of current relay to sense the current flow in the lighter. As long as the current flows in the lighter you can start your car. Simply add the contacts of this relay in series with your momentary key ignition start contact.
I have a 99 Accord and have reviewed the wiring schematic for it. The "lighter" in my car is actually a 10A accessory outlet as my car didn't come with an ashtray.
Your car starts when you activate the "starter cut relay" by turning the key whilst depressing the clutch (clutch interlock switch in a standard) or ensuring that you are in Park or Nuetral ( gear position switch in an automatic). This means the relay receives it's power from 2 switches in series. They ignition key switch and a "safety" interlock switch.
Probably the easiest thing to do is locate the interlock switch. I have a standard and I can see the interlock switch behind the clutch pedal arm without having to remove anything. If you have an automatic then you will have to locate the gear postion switch. Both switches are 2 wire devices so you simply have to break the GND wire (usually blk in Hondas) and connect the 2 new leads to your new relay - which is somehow activated by the lighter.
There is one major problem with this arrangement however.
The "starter cut relay" has the 2 contacts (the key and interlocks switches) that operate it on either side of it electrically. The key feeds +12v to the relay while the interlock switch completes the cct for the relay coil to GND (or -12V). Tie your wiring into the system by opening the lead between the interlock switch and GND. Do not tie your wiring into the system between the interlock switch and the relay! If the wiring you install in future "gnds out" in anyway you could have safety problems (starter can engage in gear-automatic or standard) not to mention that your "anti-theft" switch may no longer work. Gnding out will bypass the interlock if you place your wiring between the relay and interlock switch. However, gnding out will not bypass the interlock switch if you place your wiring between the interlock switch and gnd. The manufacturer's know this and design their switches to minimise gnding problems (all made of plastic) and they are generally of the "positive guided type" so that welded conatcts will be "forced open" upon release of activating force. An open broken switch is not a problem, your car simply won't start.
The safest way is to break the +12v lead from the key switch to the relay. Locate the wiring at the relay. The (+12V) lead wire will be BLK/WHT at the relay and the (-12V) lead at the relay will be BLU/WHT. This relay is located in the "driver's underdash fuse relay box".
The lighter must work as it did originally in order for your "anti-theft" system to work "undetected" and your lighter to work normally. Inserting anything in series to sense the current flow in the lighter may affect and reduce the current flow in the lighter. This could mean the lighter won't work (doesn't get hot enough to light a cigarette) or the lighter may work but takes a long time to heat up, or the lighter may not release because the bimettallic element in the lighter never gets hot enough to force the lighter out - in which case it could melt into your dash . I would want the lighter to work as it did before so that no problems occur and no one figures out your anti-theft system. Do you trust your friends enough to tell them about your anti-theft system? Are you sure they won't tell anyone?
So now how do we sense the current while allowing the lighter to still work? The easiest thing is probably a "DC current sensing" relay with a very low coil resistance - in the order of ohms - connected in series with the lighter. For example, if the lighter draws 10A@12V the lighter has a resistance of R=12/10=1.2ohms. The lighter is essentially "voltage operated" and any reduction in voltage caused by the series connected relay and lighter may hinder the operation of the lighter. So the relay coil resistance must be very low in comparison to the lighter resitance. If I was to guess I would think the relay coil resistance would have to be less than 10% of the lighter resistance or about 0.12ohms in order for the lighter to still function properly. Such a low value may be very hard if not impossible to find in any commercially available relay.
The sensing device must then be an electronic type device not just a straight relay type device. A relay device being a device having 4 leads- 2 leads for power (12V) and 2 leads for "dry" relay contacts. An electronic device being a device having 6 leads - 2 leads for power (12V), 2 leads for "dry" contacts, and 2 leads to connect in series with the load to sense the load.
The electronic device offers a low resistance when connected in series with the lighter and does not affect the lighter operation.
The electronic device is probably expensive if you do locate it.
You have got me interested in this project. I think I will source or make some device that will perform this function. I will post my results in future.
Good luck.
I have a 99 Accord and have reviewed the wiring schematic for it. The "lighter" in my car is actually a 10A accessory outlet as my car didn't come with an ashtray.
Your car starts when you activate the "starter cut relay" by turning the key whilst depressing the clutch (clutch interlock switch in a standard) or ensuring that you are in Park or Nuetral ( gear position switch in an automatic). This means the relay receives it's power from 2 switches in series. They ignition key switch and a "safety" interlock switch.
Probably the easiest thing to do is locate the interlock switch. I have a standard and I can see the interlock switch behind the clutch pedal arm without having to remove anything. If you have an automatic then you will have to locate the gear postion switch. Both switches are 2 wire devices so you simply have to break the GND wire (usually blk in Hondas) and connect the 2 new leads to your new relay - which is somehow activated by the lighter.
There is one major problem with this arrangement however.
The "starter cut relay" has the 2 contacts (the key and interlocks switches) that operate it on either side of it electrically. The key feeds +12v to the relay while the interlock switch completes the cct for the relay coil to GND (or -12V). Tie your wiring into the system by opening the lead between the interlock switch and GND. Do not tie your wiring into the system between the interlock switch and the relay! If the wiring you install in future "gnds out" in anyway you could have safety problems (starter can engage in gear-automatic or standard) not to mention that your "anti-theft" switch may no longer work. Gnding out will bypass the interlock if you place your wiring between the relay and interlock switch. However, gnding out will not bypass the interlock switch if you place your wiring between the interlock switch and gnd. The manufacturer's know this and design their switches to minimise gnding problems (all made of plastic) and they are generally of the "positive guided type" so that welded conatcts will be "forced open" upon release of activating force. An open broken switch is not a problem, your car simply won't start.
The safest way is to break the +12v lead from the key switch to the relay. Locate the wiring at the relay. The (+12V) lead wire will be BLK/WHT at the relay and the (-12V) lead at the relay will be BLU/WHT. This relay is located in the "driver's underdash fuse relay box".
The lighter must work as it did originally in order for your "anti-theft" system to work "undetected" and your lighter to work normally. Inserting anything in series to sense the current flow in the lighter may affect and reduce the current flow in the lighter. This could mean the lighter won't work (doesn't get hot enough to light a cigarette) or the lighter may work but takes a long time to heat up, or the lighter may not release because the bimettallic element in the lighter never gets hot enough to force the lighter out - in which case it could melt into your dash . I would want the lighter to work as it did before so that no problems occur and no one figures out your anti-theft system. Do you trust your friends enough to tell them about your anti-theft system? Are you sure they won't tell anyone?
So now how do we sense the current while allowing the lighter to still work? The easiest thing is probably a "DC current sensing" relay with a very low coil resistance - in the order of ohms - connected in series with the lighter. For example, if the lighter draws 10A@12V the lighter has a resistance of R=12/10=1.2ohms. The lighter is essentially "voltage operated" and any reduction in voltage caused by the series connected relay and lighter may hinder the operation of the lighter. So the relay coil resistance must be very low in comparison to the lighter resitance. If I was to guess I would think the relay coil resistance would have to be less than 10% of the lighter resistance or about 0.12ohms in order for the lighter to still function properly. Such a low value may be very hard if not impossible to find in any commercially available relay.
The sensing device must then be an electronic type device not just a straight relay type device. A relay device being a device having 4 leads- 2 leads for power (12V) and 2 leads for "dry" relay contacts. An electronic device being a device having 6 leads - 2 leads for power (12V), 2 leads for "dry" contacts, and 2 leads to connect in series with the load to sense the load.
The electronic device offers a low resistance when connected in series with the lighter and does not affect the lighter operation.
The electronic device is probably expensive if you do locate it.
You have got me interested in this project. I think I will source or make some device that will perform this function. I will post my results in future.
Good luck.
Thread Starter
Joined: Apr 2003
Posts: 885
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From: Camano Island, WA, USA
Re: Security Idea (skiier)
WOW, thanks, i think
so, how exactly does yours work? you push the lighter in, it sences the draw of current, and then sets off the relay to allow you to start your car?
so, how exactly does yours work? you push the lighter in, it sences the draw of current, and then sets off the relay to allow you to start your car?
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From: Great White North, canada
Re: Security Idea (DIYaccord)
I'm trying to figure that out right now. But it seems that all the solutions are expensive.
If you are technically inclined at all then check out this link:
http://www.api-usa.com/current...e.pdf
I am looking for a cheaper solution however. The expensive relay in the link will be totally reliable however and would probably work forever but I am sure there is a more specific cheaper relay available. I will keep looking.
If you are technically inclined at all then check out this link:
http://www.api-usa.com/current...e.pdf
I am looking for a cheaper solution however. The expensive relay in the link will be totally reliable however and would probably work forever but I am sure there is a more specific cheaper relay available. I will keep looking.
Thread Starter
Joined: Apr 2003
Posts: 885
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From: Camano Island, WA, USA
Re: Security Idea (skiier)
well, i think a cheaper way (the way i had in mind) was just to have a switch you would have to momentarily have to press in order to start the car (eg, the cigarett lighter or such)
i just wanna know what i could hook up the switch to that that would be momentary.
i just wanna know what i could hook up the switch to that that would be momentary.
Joined: Mar 2004
Posts: 81
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From: Great White North, canada
Re: Security Idea (skiier)
I think I have a cheap solution. At the link;
http://www.oceancontrols.com.au/relays/relays.htm
you will find a "Dual 12VDC Relay" card for $19 US.
The card operates on 12VDC. Wire the 12V power needed to operate this unit into a cct that is always live when your key is the ignition.
Use the normally open contacts of the relay output of this unit to interlock the Ignition key switch.
The unit operates on either of 2 inputs which are both referenced to GND (-12VDC). One input is a "high" input and will operate the relay if a voltage of +2.4 - 12V is applied to this input. The other input is a "low" input and will operate the relay from a range of 0 to +0.8VDC.
I have the unit to make it work. I just need a way of sensing "voltage" reliably from the current being drawn by the lighter.
Be back soon with a solution I hope.
http://www.oceancontrols.com.au/relays/relays.htm
you will find a "Dual 12VDC Relay" card for $19 US.
The card operates on 12VDC. Wire the 12V power needed to operate this unit into a cct that is always live when your key is the ignition.
Use the normally open contacts of the relay output of this unit to interlock the Ignition key switch.
The unit operates on either of 2 inputs which are both referenced to GND (-12VDC). One input is a "high" input and will operate the relay if a voltage of +2.4 - 12V is applied to this input. The other input is a "low" input and will operate the relay from a range of 0 to +0.8VDC.
I have the unit to make it work. I just need a way of sensing "voltage" reliably from the current being drawn by the lighter.
Be back soon with a solution I hope.
Joined: Mar 2004
Posts: 81
Likes: 0
From: Great White North, canada
Re: Security Idea (skiier)
Better, easier idea.
Install a power transistor in series with the lighter. Install the lighter in the emitter and tie the collector directly to +12VDC. The base of the transistor is connected to +12VDC thru a resistance ( a low voltage relay coil). This resistance also limits the base current.
A transistor uses a small current (base current) to produce a large current (collector current). The emitter current is that which feeds the lighter and is the sum of the base and collector currents. Normally you set up a transistor so that a certain value of base current PRODUCES a certain value of collector current. But in this case we are working backwards by using the lighter resistance and the assumed voltage at the lighter to calculate the emitter current (and collector current) so that we can find the required or "produced value" of base current. Once we know the base current we calculate the volatge drop across the resistance in the base cct to find the base resistance. This base resistance we need to know to find the proper relay that will work with this transistor.
To make a long story short. I figured out how to do this with a transistor and a relay. I just need to find the components. Keep you updated.
Install a power transistor in series with the lighter. Install the lighter in the emitter and tie the collector directly to +12VDC. The base of the transistor is connected to +12VDC thru a resistance ( a low voltage relay coil). This resistance also limits the base current.
A transistor uses a small current (base current) to produce a large current (collector current). The emitter current is that which feeds the lighter and is the sum of the base and collector currents. Normally you set up a transistor so that a certain value of base current PRODUCES a certain value of collector current. But in this case we are working backwards by using the lighter resistance and the assumed voltage at the lighter to calculate the emitter current (and collector current) so that we can find the required or "produced value" of base current. Once we know the base current we calculate the volatge drop across the resistance in the base cct to find the base resistance. This base resistance we need to know to find the proper relay that will work with this transistor.
To make a long story short. I figured out how to do this with a transistor and a relay. I just need to find the components. Keep you updated.
Member
Joined: Nov 2003
Posts: 7,240
Likes: 1
From: Michigan State University, USA
Re: Security Idea (skiier)
i know u said u didnt wanna have this be fuel related....but.....apparently u can run a switch on the line from either the ecu to the fuel pump, or the power supply to the fuel pump......im not sure exactly how it works, but its like a $10 radio shack DIY that my buddy is doing on his FC.....just thought id throw that out there after this link was brought back from the dead.....
Joined: Mar 2004
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From: Great White North, canada
Re: Security Idea (DIYaccord)
Sorry DIYaccord. There is no easy way to just "hook-up" a momentary switch. You must measure some voltage change to sense that the lighter is on/off. The lighter is a self-contained unit. The lighter simply expands when heated and pops out to shut off. The power points to the lighter body never change state. You can't measure a voltage "change" anywhere.
If you want to use the lighter as normal then you must sense current flow only.
There is no other way of doing it.
If you want to use the lighter as normal then you must sense current flow only.
There is no other way of doing it.
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From: nyc, USA
Re: Security Idea (fluxion)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fluxion »</TD></TR><TR><TD CLASS="quote">suggestion for autos, disable the shiftlock release so you need the key to get it out of park.</TD></TR></TABLE>
lol good trick but in a way annoying, youll need a spare key with ya everywhere u go to get it to release :\ i wouldnt mind doing it though, how u disable it?
lol good trick but in a way annoying, youll need a spare key with ya everywhere u go to get it to release :\ i wouldnt mind doing it though, how u disable it?
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