:yeahthat:
Technical How to make a OCS sensor
- Thread starter gsc1ugs
- Start date
Currently reading:
Technical How to make a OCS sensor
From what I've found on the internet this type of circuit works on some cars so maybe it is as simple as sending the correct resistances to the airbag computer?
Last edited:
I see your point, but i doubt it, the OCS mat doesn't just check to see if someones there it "classifies" them.
attached to the actual mat is a computer that i presume does the classification and in turn communicates this to the car.
the circuit with lots of resistors is just emulating the mat being in a certian state (ie occupied with an adult), beacause often a "point of faliure" is one of the many tracks on the OCS mat (i have an old one ill post pictures if you want)....this "state" allows the OCS computer to do its thing then relay this back to the car....
the reason why i doubt the simple circuit will work is because it is "dumb" i.e. doesn't communicate with the car just "presents a load" whereas i believe the OCS computer will communicate with the car.....after all, if it were THAT simple, the ones on ebay would be tiny, and very very cheap....
(BTW im at work so have no sound, so cant watch the video)
attached to the actual mat is a computer that i presume does the classification and in turn communicates this to the car.
the circuit with lots of resistors is just emulating the mat being in a certian state (ie occupied with an adult), beacause often a "point of faliure" is one of the many tracks on the OCS mat (i have an old one ill post pictures if you want)....this "state" allows the OCS computer to do its thing then relay this back to the car....
the reason why i doubt the simple circuit will work is because it is "dumb" i.e. doesn't communicate with the car just "presents a load" whereas i believe the OCS computer will communicate with the car.....after all, if it were THAT simple, the ones on ebay would be tiny, and very very cheap....
(BTW im at work so have no sound, so cant watch the video)
Last edited:
Even though the incessant airbag failure warning is annoying and even though the OCS is expensive, it's really compromising your passenger's safety to mess around with dumb resistors. The OCS monitors not just the weight/size of the passenger but where they're sat in the seat in order to compute and have the crash data all set ready to trigger the correct airbags and at the best times in the event of impending passenger death time
To tell it there's a heavy and full size adult in the middle of the seat when there isn't is playing not with your life but someone else's. A dumb OCS is literally a dumb ass idea
To tell it there's a heavy and full size adult in the middle of the seat when there isn't is playing not with your life but someone else's. A dumb OCS is literally a dumb ass idea
Last edited:
apparently it works https://www.fiatforum.com/stilo/268543-ocs-help.html
All seems very messy to me.
it does who the hells soldering is that?:yuck:
totally agree....
and yes thats some "experimental" soldering lol, id be sacked if i did that....
Can't see anyone on that thread, or anywhere else for that matter, who's crashed their car with a passenger in it to confirm it works.
what we need to do then is ask if anyone has done this mod and has the ability to check with FES if it registers as passenger present or not!
has anyone done this mod who has FES, if so could you hook it up and see if it reports the seat as occupied or not?
surely if the ECU sees it as occupied then it will deploy the passenger airbag, the question is does it report it as fully laden or not i was always under the impression that the OCS detected weight as well as presence as the passenger airbag was of a 'multistage' variety
has anyone done this mod who has FES, if so could you hook it up and see if it reports the seat as occupied or not?
surely if the ECU sees it as occupied then it will deploy the passenger airbag, the question is does it report it as fully laden or not i was always under the impression that the OCS detected weight as well as presence as the passenger airbag was of a 'multistage' variety
or that... didnt read before i posted... schoolboy error
I'm a bit confused(nothing new to be honest) ...
Is this correct?
The tracks on the mat detect a load and send a range of resistances to the chip attached to the mat. The chip then sends the correct signal to the OCS computer and no dash warning light is shown, airbags deploy accordingly.
Is this what is supposed to happen?
If this simple circuit were to some how emulate the tracks on the mat and supply the chip attached to the mat with the correct resistances for an adult(for example). The OCS computer would then think the seat was occupied by an adult and deploy?
Or have I got this completely wrong and this simple circuit is supposed to some how bypass the chip on the mat, then fool the OCS computer and allow the airbag to deploy?
apparently it works https://www.fiatforum.com/stilo/268543-ocs-help.html
Done by
https://www.fiatforum.com/members/mihaitza83
Check out post 44 of this thread.
https://www.fiatforum.com/stilo/150303-emulating-passenger-ocs-sensor-3.html
Last edited:
I'm a bit confused(nothing new to be honest) ...
Is this correct?
The tracks on the mat detect a load and send a range of resistances to the chip attached to the mat. The chip then sends the correct signal to the OCS computer and no dash warning light is shown, airbags deploy accordingly.
Is it is then is this what is supposed to happen?
If this simple circuit were to some how emulate the tracks on the mat and supply the chip attached to the mat with the correct resistances for an adult(for example). The OCS computer would then think the seat was occupied by an adult and deploy?
Or have I got this completely wrong and this simple circuit is supposed to some how bypass the chip on the mat, then fool the OCS computer and allow the airbag to deploy?
you are correct in the operation of the OCS, but the simple circuit is designed to COMPLETELY bypass the OCS mat and its computer, and connect directly to the cars loom....ie communicate with the airbag computer....now you see why i think there is no chance of it working! a diode and a resistor cant talk to each other let alone a computer
you are correct in the operation of the OCS, but the simple circuit is designed to COMPLETELY bypass the OCS mat and its computer, and connect directly to the cars loom....ie communicate with the airbag computer....now you see why i think there is no chance of it working! a diode and a resistor cant talk to each other let alone a computer
Thanks.
Agreed, its a load of sh*t ...
danhans115 says in post #31 of that thread "emulates the seat being empty" meaning the airbag would never fire whether it was occupied or not. Just to add to the confusion.
danhans115 says in post #31 of that thread "emulates the seat being empty" meaning the airbag would never fire whether it was occupied or not. Just to add to the confusion.
Thanks thats all I need ...
danhans115 in post 31 emulates an empty seat. Not sure why you'd want to do that, sounds dangerous to me.
mihaitza83 in post 32 emulates an occupied seat. This I can understand but after reading the link John supplied probabely just as dangerous.
I've read enough, my advice, buy and fit a new mat.
Play safe you guys.
Last edited:
is it an MOT fail?
There's a very good chance it will be in the near future ...
Perhaps all it does is keep the warning light switched off.
bad news about MOT fails
IF the resistor mod shows as unoccupied then thats bad news
but
IF the resistor mod shows as occupied then it will deploy the airbags at full whack then its not so bad
i understand that dual stage is a more advanced way of doing things and is ultimately 'safer' after reading how the ocs hangs with rest of the system but it kinda makes me think of days gone by where there was a 'dumb' airbag ecu that ran driver and passenger airbags it would deploy both regardless of weight or position in the seat to me this is infinately safer than it not going off at all.
At the risk of getting flamed im not disregarding what shadeyman has said but simply disagreeing. im personally not in a position to spend £240 on an OCS mat anytime soon so if i can ensure that my passenger airbag will deploy for £3 of resistors then im in.
ive also heard that if the ecu picks up an OCS fault then the passenger airbag goes into a 'safe mode' and assumes that the mat is fully loaded and will deploy at full capability anyway. if the resistor mod emulates a fully laden OCS mat then it will kill the dash warning but operate in this 'safe mode' so my passengers will be no better off in the event of an accident but at least i wont have the damn beeping and at least it will still go off!
IF the resistor mod shows as unoccupied then thats bad news
but
IF the resistor mod shows as occupied then it will deploy the airbags at full whack then its not so bad
i understand that dual stage is a more advanced way of doing things and is ultimately 'safer' after reading how the ocs hangs with rest of the system but it kinda makes me think of days gone by where there was a 'dumb' airbag ecu that ran driver and passenger airbags it would deploy both regardless of weight or position in the seat to me this is infinately safer than it not going off at all.
At the risk of getting flamed im not disregarding what shadeyman has said but simply disagreeing. im personally not in a position to spend £240 on an OCS mat anytime soon so if i can ensure that my passenger airbag will deploy for £3 of resistors then im in.
ive also heard that if the ecu picks up an OCS fault then the passenger airbag goes into a 'safe mode' and assumes that the mat is fully loaded and will deploy at full capability anyway. if the resistor mod emulates a fully laden OCS mat then it will kill the dash warning but operate in this 'safe mode' so my passengers will be no better off in the event of an accident but at least i wont have the damn beeping and at least it will still go off!
bad news about MOT fails
IF the resistor mod shows as unoccupied then thats bad news
but
IF the resistor mod shows as occupied then it will deploy the airbags at full whack then its not so bad
i understand that dual stage is a more advanced way of doing things and is ultimately 'safer' after reading how the ocs hangs with rest of the system but it kinda makes me think of days gone by where there was a 'dumb' airbag ecu that ran driver and passenger airbags it would deploy both regardless of weight or position in the seat to me this is infinately safer than it not going off at all.
At the risk of getting flamed im not disregarding what shadeyman has said but simply disagreeing. im personally not in a position to spend £240 on an OCS mat anytime soon so if i can ensure that my passenger airbag will deploy for £3 of resistors then im in.
ive also heard that if the ecu picks up an OCS fault then the passenger airbag goes into a 'safe mode' and assumes that the mat is fully loaded and will deploy at full capability anyway. if the resistor mod emulates a fully laden OCS mat then it will kill the dash warning but operate in this 'safe mode' so my passengers will be no better off in the event of an accident but at least i wont have the damn beeping and at least it will still go off!
I too have been told that the airbags drop into "safe mode" and will deploy even if the warning light is on.
So in the interests of your passengers health DO NOT add £3 of resistors to something thats doing its best to protect your friends and family ...
