deswong
Oct 29, 2008, 03:10 AM
This question doesn't directly relate to RC gear but I'm starting to scratch at the walls in frustration on this one...
I want to use the signal from my digital tilt sensor (car alarm) and split that off into the alarm and also into a third party monitoring box.
I have diode'd the output from the tilt sensor into my car alarm and the third party box, but because of the 0.6v drop across the diode it means that the pre-warn does not work (as the pre-warn doesn't put out the full 12v/5v/whatever voltage to trigger the alarm as a prewarn).
So it does work and recognise a full trigger, and everything works but the pre-warn.
I've been scratching my head over this for a while now, and I think one way to sort this out is to optically isolate the output - basic theory is to use the output from the tilt sensor into an opto-coupler IC, and if there is one that can take the one input and have two optical receivers (maybe wrong terminology) that then I would guess have to trigger a transistor to give the same voltage output as what is going in? Have I successfully confused everyone?
The car alarm installers just can't see what I am getting at - they have said that it is too hard and I know a lot more than they do about the interfacing of sensors - "We just install what we are trained to do - we don't know what you are talking about".
I have tried doing this without the diode but that results in false triggers as soon as the alarm is armed. so I need a way where the output from the sensor is also passed onto the alarm module, where the input=output but isolated.
I want to use the signal from my digital tilt sensor (car alarm) and split that off into the alarm and also into a third party monitoring box.
I have diode'd the output from the tilt sensor into my car alarm and the third party box, but because of the 0.6v drop across the diode it means that the pre-warn does not work (as the pre-warn doesn't put out the full 12v/5v/whatever voltage to trigger the alarm as a prewarn).
So it does work and recognise a full trigger, and everything works but the pre-warn.
I've been scratching my head over this for a while now, and I think one way to sort this out is to optically isolate the output - basic theory is to use the output from the tilt sensor into an opto-coupler IC, and if there is one that can take the one input and have two optical receivers (maybe wrong terminology) that then I would guess have to trigger a transistor to give the same voltage output as what is going in? Have I successfully confused everyone?
The car alarm installers just can't see what I am getting at - they have said that it is too hard and I know a lot more than they do about the interfacing of sensors - "We just install what we are trained to do - we don't know what you are talking about".
I have tried doing this without the diode but that results in false triggers as soon as the alarm is armed. so I need a way where the output from the sensor is also passed onto the alarm module, where the input=output but isolated.