Seat belt as a kill switch: need suggestions

  • #1
So I'm planning on making the seat belt to work as a kill switch for an automobile using a Reed switch and a magnet. But I'm confused as to whether I should buy or make one. If I should buy it where should I go? Please give me your suggestions as I have to find the most efficient way and I have very little time. Thank you.
 

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  • #2
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Most newer cars already have seatbelt sensors built in. Could you hijack that signal??
My car even goes so far to have a weight sensor in the passenger seat to suppress the alarm when no one is sitting in it.

However from a safety standpoint a kill switch such of this might end up being more dangerous. What happens if the sensor fails when you're driving down the highway? Or if you've been out camping in the middle of nowhere and the sensor fails?
 
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  • #3
Most newer cars already have seatbelt sensors built in. Could you hijack that signal??
My car even goes so far to have a weight sensor in the passenger seat to suppress the alarm when no one is sitting in it.

However from a safety standpoint a kill switch such of this might end up being more dangerous. What happens if the sensor fails when you're driving down the highway? Or if you've been out camping in the middle of nowhere and the sensor fails?
Actually this vehicle is for a competition and it won't be hitting the road much other than the few days in which the competition will take place.
 
  • #4
phinds
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Actually this vehicle is for a competition and it won't be hitting the road much other than the few days in which the competition will take place.
So you're saying you don't care if it's really dangerous during those few days?
 
  • #5
donpacino
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So you're saying you don't care if it's really dangerous during those few days?
no, he is saying the solution doesn't need to work for 30000 hours before failure, just a few.
 
  • #6
donpacino
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you might be better off buying the sensor. I'm sure they have commercially available parts. go to sites like digikey or mouser
 
  • #7
phinds
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no, he is saying the solution doesn't need to work for 30000 hours before failure, just a few.
Sure, and I agree it's almost sure to be safe but "almost sure" isn't all that great when your life could be on the line.
 
  • #8
Sure, and I agree it's almost sure to be safe but "almost sure" isn't all that great when your life could be on the line.
Actually there is no threat to life,its an electric motor driven vehicle that would barely cross 25kmph
 
  • #9
sophiecentaur
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Sure, and I agree it's almost sure to be safe but "almost sure" isn't all that great when your life could be on the line.
That proposed modification could be contravening your contractual agreement with your insurers. You would be advised to ask them or you could find you were not covered, if you were to have an accident and the assessor were to poke around. In the case of this particular vehicle, I would think he may be very interested in any mods you had done.
 
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  • #10
donpacino
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there is a large difference between a design that will olny last a few days, and a design that is 'almost sure.'
 
  • #11
sophiecentaur
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there is a large difference between a design that will olny last a few days, and a design that is 'almost sure.'
If I were going to use a parachute just once - tomorrow - I would want to be pretty sure it was going to work and the 30,000 hour figure would be the one to give an indication of risk. Just as with radio nucleides, even one with a half life of 1,000,000 years could go off now. With a potentially lethal thing like a competition car, I would have a similar attitude. For a radio set or a gas cooker, I might be a bit less fussy. But this is bordering on a duty of care issue (for other competitors) and, as such, should be treated with a fair level of seriousness. You may find something in the competition rules to tell you what's acceptable or not.
I have a worry that this is outside the remit of PF.
 
  • #12
donpacino
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If I were going to use a parachute just once - tomorrow - I would want to be pretty sure it was going to work and the 30,000 hour figure would be the one to give an indication of risk. Just as with radio nucleides, even one with a half life of 1,000,000 years could go off now. With a potentially lethal thing like a competition car, I would have a similar attitude. For a radio set or a gas cooker, I might be a bit less fussy. But this is bordering on a duty of care issue (for other competitors) and, as such, should be treated with a fair level of seriousness. You may find something in the competition rules to tell you what's acceptable or not.
I have a worry that this is outside the remit of PF.

If you were going to use a parachute 30,000 times that would be one thing, as you need to worry about the durability of the cloth, effects of repeated use on the lines. If you plan on using it once, and you KNOW it will work a few times, then that is fine and safe, because you don't need to worry about the cycling effect.

when i said 30,000 hours i meant 30,000 hours of use, of plugging and unpluggng it. granted the number was pulled out of my butt
 
  • #13
D H
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However from a safety standpoint a kill switch such of this might end up being more dangerous. What happens if the sensor fails when you're driving down the highway? Or if you've been out camping in the middle of nowhere and the sensor fails?
Even worse than failing, what if the sensor works?

Passengers (particularly kids in the back seat) unbuckle themselves all the time. While that's worthy of a stiff reprimand, it should not be a death sentence. This kill switch is a potential death sentence. Suppose you're driving on a curvy mountain road (no guard rails) in Colorado with a thousand foot drop to one side toward that campsite in the middle of nowhere. Suppose that, just as you're about to round yet another curve, your passenger unbuckles the seat belt and the kill switch turns off the engine.

Actually this vehicle is for a competition and it won't be hitting the road much other than the few days in which the competition will take place.
This is a massively bad idea. What made you think this idea would help you win the competition?
 
  • #14
berkeman
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@TheNerdyGuy -- I think you have gotten good responses in this thread, and I hope you take them to heart.

BTW, there is a difference between a kill switch, and an interlock that doesn't let you start the vehicle if the seat belts aren't fastened for occupied seats. You might explore that option instead. Thread is closed.
 

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