adding a proximity sensor to a shock sens

I want to add a proximity sensor to the same shock sensor input because all this alarm has is one sensor input. I was wondering if this would be the correct way to do this or does each sensor need diodes on the two alarm inputs? I have a few 1N5819 diodes I can use if this will work. I may have to extend the wires a bit, but other than that I just want to make sure to isolate each sensor so they work properly and I can set each correctly without affecting each other.

I forgot to mention the colors on the proximity sensor. From the included manual(Sheet)these are:
Green = Pre-warn
Blue = Alarm (Hard) Trigger
Black = Ground when armed
Red = Constant +12v

You can do that, just diode isolate but run power and ground for the proximity sensor separate. Make sure to fuse the power feed, 3A is more than enough.

Thanks! I didn't think about that. Having the power and ground separate will help since I may need to extend the wires a bit. The proximity sensor has nice long wires, but I don't think they will be long enough to reach where I want to put it, so I will only need to extend the trigger wires I think. I'm still working with all this on my desk to try and get it all set up outside for the most part. It's just easier to solder on the desk than under the dash.

catback wrote:

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You can do that, just diode isolate but run power and ground for the proximity sensor separate. Make sure to fuse the power feed, 3A is more than enough.

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Also, would it be better to diode both sensors or does it really not make any difference? I'm just thinking about this and the main thing is to prevent or at least keep most false alarms to a minimum. I guess I could do both to keep each one from affecting the other. Not sure since I have never done this.

4 diodes one on each pre-warn and trigger

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Thanks, I thought I may go that route to completely isolate each one.

howie ll wrote:

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4 diodes one on each pre-warn and trigger

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I finally got this installed, but plugged the sensor to my radio 12 volt so I don't have the fuse yet. Which brings me to this question, what's the reason you don't want to plug to the same power and ground as the shock sensor coming from the alarm? I'm just curious because as it is now, the sensor is always getting power from the battery. I'm not sure if the power from the alarm to the sensor is always on or only when the alarm is armed. I'm sure it may not be much but I just want to make sure I don't put any other unnecessary drains on the battery. Well that's my thinking anyway.

As for the sensor, it takes a bit of tuning it to get it where it will not give you false alarms, but so far it seems to work. I did end up using diodes on both triggers for the shock and the proximity sensor.

The internal power supply on the alarm isn't powerful enough to handle the load current of the two sensors. They will be more stable that way, just as some cars have multiple ACC IGN and start at the ignition switch.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Thanks Howie, that makes sense. I finally got in touch with them and they said it would be fine to put them together, but it's working fine as is, so I won't mess with that. I just need to add the fuse.

howie ll wrote:

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The internal power supply on the alarm isn't powerful enough to handle the load current of the two sensors. They will be more stable that way, just as some cars have multiple ACC IGN and start at the ignition switch.

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