The DEI 504D Double Guard Stinger Shock Sensor can be added to the stock BMW alarm for about $10

The stock alarm only alerts to an external problem if the tilt sensor is activated as if someone is jacking up the car. If someone were to hit your car while parked, the alarm would not trigger.

The DEI shock sensor adds an adjustable sensitivity sensor that will trigger the alarm when the car receives a "thump". It connects with just three wires: +Pos - Neg and the trigger.
There are 4 wires. The blue and green are the triggers and provides a "warn" trigger (light thump) and an "alarm" trigger (heavier thump).
The stock alram does not support a "warn" trigger so we will tie the blue and green together.


Attachment 116943


I installed the sensor along with the stock motion sensor in the headliner. Remove the trim panel that looks like a "vent" - that is the motion sensor. Just pull down an edge and work it loose.
Attachment 116941

This shows the cable after I disconnected the panel
Attachment 116942

The wire diagram. We will use 1, 8, and 7
Attachment 116940

You need to tap into the power, ground and the blue trigger wire. The alarm is triggered when pin 7 is grounded - which is what the shock sensor provides. The blue wire goes to ground when a shock is detected.
I chose to scrape away the insulation and solder in the leads.
Attachment 116937

Completed sensor lead attached
Attachment 116938

I applied doublestick tape and attached the sensor to the roof panel. Hopefully this tape holds when it gets good and hot this summer. Place the sensor so that you can get to the adjustment screw.
Attachment 116939


Alarm Demo:
http://www.youtube.com/watch?v=yyWTmm75rD0


Negative side effects to work out:
- If I lock the doors with the FOB when a door is still open - like with a passenger, the sensor activates the alarm when the door is closed.
- If the car is locked and alarm set, I can open the trunk. When I slam the truck closed, the sensor will activate the alarm.

So the stock alarm is smart enough to handle these situations but the alarm is active enough to allow this grounding trigger from the sensor to still activate the alarm. I will adjust my behavior to work around the limitation while I think on what to do about it.

EDIT:
** My first idea to check out: Pin 5 is supposed to be the lead that runs the LED on the mirror. I will check to see what voltage is on that pin before and after the alarm is set. It may turn out that the LED lead has power only after all the doors are closed and the alrm is active.

Excellent ! :twoup:

Some comments:

• indeed too bad our cars don't support the "warn" option
• I wouldn't set it to too sensitive - I've seen car alarms go off in parking garages just from the sound/shock wave of doors closing from nearby cars.
• The LED on mirror idea might work - doesn't it have power to provide warning signals? eg. fast blink if you lock and a door is still open...

Could only find one ebayer who would ship to Holland - is this same thing ? - looks slightly different: http://cgi.ebay.com/504D-Double-Guard-Stinger-Shock-Sensor-DEI-NEW-/330520702840?pt=LH_DefaultDomain_0&hash=item4cf491af78

That is the same one. It does look a little different - they probably have different manufacturers over the years.

Good tip on the sensitivity. I have never lived with one of these on a car so getting it adjusted will be interesting. I also wonder about heavy rain on the roof.

Good add-on; might be perfect to alert to door dingers. Wonder if it'd be mod-able to trigger a camera ! Do you know if the wiring is the same for Comfort Access?

I've found this and others with 504D Viper Name brand by going thru MrRebates [link in my signature].

Mine is Comfort Access. I don't think it is different for non CA.

Very Cool ! :thumbsup:

I checked out line 5 which is supposed to be for the LED lamp on the mirror. I didn't get a voltage off of it while the LED blinked. My guess is it does not power the LED directly but more likely sends a data signal to the mirror electronics and it determines the flash rate.

Thanks NoQuarter. Glad to see you tried it after I suggested the idea a few weeks ago I will do this in the spring. What car is honking in the video is it the E60 or another car??

That horn is the stock alarm - it surprised me too. If you set off the alarm from the motion sensor you don't get the horn but with shock sensor the horn went off as well. I'm thinking that if the hood or trunk lid were forced open to set off the alarm the horn would sound also. :confused:

By tying the blue and green wires together, you are effectively using only the warning portion of the shock sensor. There's really no need to tie them together, you could just use the wire that supports the first or second stage shock level then cut the other wire.

Another thing to try would be to mount the sensor to a wiring harness rather than the roof sheet metal. The shock sensors are quite sensitive, they can detect vibration quite easily. The wiring harnesses in the roof will more than likely run through other portions of the car besides the roof. This will allow the sensor to detect vibration easier from other portions of the car.

Sweet!! this is the one ive been looking for!.. i saw this done on an e46 and couldnt remember what that sensor was called lol.. (brand) but thanks for the DIY!!! :twoup:

Why are you not using wire taps instead of splicing them manually?

In general I just try to avoid wire taps in all cases. In this case, those wires are pretty small and getting a tap that will pinch those wires correctly was more difficult than making a proper, permanent connection. Something else to keep in mind, a lot of these retrofit projects require connecting into the CAN BUS wires which is the same as making a connection into a computer network cable. I don't want a half-a$S connection hidden away in some difficult location that causes intermittent problems.

Just a quick update on this....

So part of the problem with this install is that the sensor is always powered and if the driver door is closed first (with the alarm having already been armed by locking the car), other doors closing will trigger the alarm.

I looked at pin 5 again and I made a mistake the first time.Pin 5 grounds the LED to make it flash but the signal is intermittant (same as the flash rate).

I think an improvement like this would work: Create a latch type circuit that accepts the low voltage intermittant signal from pin 5 and us it to power the shock sensor. The latch would need to operate on a timer delay because the LED starts to flash even before the doors are closed (I think).

I tested this DIY and works!

But ..... if the shock sensor is triggered the alarm will go off 30 seconds, then other 30 seconds
and then it will stop but also inhibiting the sensors so if you kick the car again or break into the car, the alarm will not be triggered.


I apologize for my english. Thank you very much

I wonder if this is a regional difference in the alarm settings and how the wireing was done? When I tested mine I tested multiple times and the alarm went off each time.

I was just wondering... this has anything problems with the fiber optics... and also i understand that a alarm can be added by BMW as well... did you have anything added from them.. or is this just in addition to using your key fob?

This has no issues with the fiber optics in any way so no worries there. This was with my existing factory alarm.

:wow:looks like a soon to be project for me!!

O.E.M. add on alarm
 

Great article / post . I just bought a 528i (e60) and for some reason the jealous? neighbors kids get a rush from $#%ing with my car. They got the temp tag and ripped off the metal preownd tag. No notice no nothing from my stack BMW alarm . Little did I know. This post is definitely a try -it-on weekender. Thanks .

OP, thanks for posting, how is it performing when in rain as the sensor location is on roof.