Thread: Seat belt warning system for rear seats - for safety precautions - how can i do this?

after you said young ones, i completley understood

i have always wondered if some cars use a optical sensor, or a momentary switch inside the buckle latch-- 'i think' that most of them use a switch inside the latch... so if they did, and i were to setup a system like this for myself:

as long as the seatbelts bolt to the metal, and you do not need to modify the belt latch(modifying the latch, or it attachment method in any way could possibly hurt the integrity of it--which would be just as bad as not using the belt...), or any of its parts to make it work, i would use some similar mouting belt latches from the drivers seat of some junkyard cars, and would wire the switches to the switched power from behind the radio, and hook each latch up to a LED on the front panel, so that anytime the car is on, and the seatbelts are not connected, the light will be on.

Originally Posted by soundman98

after you said young ones, i completley understood

i have always wondered if some cars use a optical sensor, or a momentary switch inside the buckle latch-- 'i think' that most of them use a switch inside the latch... so if they did, and i were to setup a system like this for myself:

as long as the seatbelts bolt to the metal, and you do not need to modify the belt latch(modifying the latch, or it attachment method in any way could possibly hurt the integrity of it--which would be just as bad as not using the belt...), or any of its parts to make it work, i would use some similar mouting belt latches from the drivers seat of some junkyard cars, and would wire the switches to the switched power from behind the radio, and hook each latch up to a LED on the front panel, so that anytime the car is on, and the seatbelts are not connected, the light will be on.

Thanks!
Of course i dont wanna put safety in risk when making these. So i dont wanna interfere with the seat belt/latch, just wondering if its possible to do this on the lower part of the lower belt since its there that the seat belt will go.

i know all cars are different, and i have seen seatbelt latch styles vary with where they are located in the car, so i can't be 100% confident that you will be able to make it work in your, or any car, but if your belt latches are all the same all around the car, and if your belts easily bolt to the floor, and if your latch uses a switch instead of a optical sensor, it should work.

thats a lot of 'if's'...

Originally Posted by soundman98

i know all cars are different, and i have seen seatbelt latch styles vary with where they are located in the car, so i can't be 100% confident that you will be able to make it work in your, or any car, but if your belt latches are all the same all around the car, and if your belts easily bolt to the floor, and if your latch uses a switch instead of a optical sensor, it should work.

thats a lot of 'if's'...

the front seat belts are different from rear seat blets and so are the lower belts.

Optical sensors as a mouse has got ??? I mean like the ones we have in our pc mouses???

FYI - I was amused when I saw how Volvo did their "people in seat" sensing way back last millennium.... A simple spring switch (contacts) that pulled apart under the seat (maybe technically referred to as an R-Grav switch - ie, As the R's hit the seat, gravity pulls it further down....?? LOL)

To think that I was working with people that were using radiation detectors to detect people! (about 300 counts per minute as I recall.)

if the front belt attachments are different than the rears, then i don't know if it would be possible in your car-- you could try it, but any way that i can try to explain it is going to sound like i am recommending you hack up the latch, which could lead to it failing in a crash.

i am thinking of a optical proximity type sensor like this-- http://parts.digikey.com/1/parts/946...a0902-011.html.

i really don't know if any seat belts really use them, but i wouldn't doubt it...

I think there have been various systems including continuity, Hall, interruption (photo, reed & Hall), microswitch...

Normally I'd also go for a photo-interruptor, but dirt would be a issue.
I'd suspect they use a magnetic system for reliability - maybe a reed, possibly a Hall.


I'd probably set up a cross-belt continuity system that if broken whilst the engine is on or vehicle moving, enables an oscillator connected to a Tesla coil across the belt. Whilst often producing an audible alert when activated, it is also a good deterrent - er, um... preventative system - users soon learn when NOT to unbelt themselves (it's my job to do the belting!).

It seems there are a lot of options and of course i dont wanna put safety in risk so i will go for an option that doesnt interfere with safety concerns so i guess your ideas may have some choice to live! I was thinking in fact in some kind of sensor that would be activated upon belt being used or something near that !

Or the simple approach, solder a wire to the buckle, duct tape the wire up the belt so it goes into to car. Solder a wire to the latch. when the metal buckle hits the latch, it completes a circuit shutting off or turning on an LED up front.