alarm alarm alarm

[vic]

Hi fitted the alarm to my sumo. Everything is working perfectly. However i am wondering where i can fit the ultrasonic sensors. I am told that they should be fitted in a high place in the shape of a V i.e the beams of each sensor is supposed to hit the other.

Has anybody fitted these sensors and if yes, where did you fit them?

Your help would be appreciated.

Regards

Vic

[Grease Monkey]

Unless it's one designed specifically for a convertable you may have lots of issues with it setting itself off all the time.

How about under the bottom corners of the dash, centreing on the gearstick or thereabouts?

[nuf_said]

How about in the driver's footwell - set fore and aft, one behind the dash and one above the pedals. No-one will nick it from the passenger side.

Or, never let it out of your sight (sad I know).

Nuf said.

[Robin427]

How many cases have there been of stolen Cobras? Some chap from OriginB2 I was e-mailing today had a V12 Dax stolen some time back, but they're not the kind of cars you'd really steal to order and a bit conspicuous for joy riders? I suppose an alarm might help stop vandalism, but if someone wants to slash your car with a Stanley knife, a box of electronics isn't going to stop that. Just a thought...

With a battery cutoff switch, removeable steering wheel and perhaps an immobiliser, no-one is going to drive off in your car. If they are that organised to get it towed away, then an alarm probably wouldn't stop them either.

[jenny]

In the drivers footwell is probably the best place, otherwise it'll be going off all the time

I know that the cobs hardly ever get nicked, but we put the alarm on ours to stop kids climbing all over it... came back from shopping once to actually find someone sitting in it having their photo taken

[tonym]

I've used a microwave alarm rather than an ultrasonic purely because the alarm will sound every few minutes with ultrasonics no matter where you site it. With my microwave it produces two microwave "bubbles", if the first is broken then there is a high pitch siren if the second bubble is broken then the alarm goes off proper. It does keep people at a distance. hth

[Safetyspice]

Hi,

Would they work if you put them under the bonnet towards the top?

I am designing an alarm for mine at the mo, its only function is to cut the main circuit to the electric fuel pump and to make an emense noise when triggered. ( I am fitting 6 110 dB sound bombs in it!!) it will also be powered by a remote 12v battery hidden out of the way)

Regards
Garry

[FMAN]

Ultrasonic sensors require a closed environment otherwise the ultrasonic waves leak out and if reflected back in by something moving will trigger an alarm. If you have this under the bonnet anything blowing underneath the car/ in front could trigger the alarm. As tonym suggests a microwave sensor is the most suitable for cobras.

Regards

Neil

[vic]

Thank you for your posts. I'll have to look into the microwave option, however i doubt they are available for my alarm version. Microwave seems more reliable, besides you never know when you need to defrost something

At the moment i'm considering fitting them in the door in the bend at the top where the door carries on to the dash. Fitting them flush to the bodywork from the inside.

The only problem with this setup i can foresee is in case i need to take off the door. Apparently you cannot cut the wire and put it plugs as this equipment is very sensitive and it would cause it to malfunction.

Any thoughts on the above.

Vic

Fantastic weather today..... wish the cob was ready for cruising..

[oglyoodoo]

"The only problem with this setup i can foresee is in case i need to take off the door. Apparently you cannot cut the wire and put it plugs as this equipment is very sensitive and it would cause it to malfunction."

Vic

I would be very surprised if there would be a problem with a Plug and Socket on an alarm sensor. Having said that there are some very dubious connectors about particularly many automotive ones.

Most alarm sensors have some electronics built into them so the low level signals are amplified and processed directly at the sensor to give an Alarm on or off output signal. I suppose it would be possible to design an alarm with very low level signals on the wires but that would almost certainly make it very prone to spurious false alarms and would be pretty poor design practice.

If it were me I would set it up on the bench and measure the alarm output signal to make sure there is a change of a few volts when the alarm is triggered. If it does then I would be happy to fit a good connector preferably with gold plated pins on both halves. A good waterproof connector isn't cheap though. Maybe a small 9 way D Type connector wrapped up would be OK but then there may be problems getting such a large connector through the door. A small LEMO connector would be a very good choice but they are expensive. Do a google search or look through the vast range of connectors on the Farnell or RS Web sites web site..

www.farnell.co.uk
www.rswww.co.uk

HTH

Denis