Electromagnetic Parking Sensors Work!

[Ryggwelter]

Hi all,

Thought you might be interested, I've just finished fitting an aftermarket reversing sensor system - and it works really rather well.

I didn't like the idea of drilling holes in the bumper for ultrasonic transducers so I thought I'd try one of the electromagnetic ones.

Parking Dynamics (www.parkingdynamics.co.uk) appear to be the speciaists but I went for a cheap Chinese one off ebay. Full manufacturers' info here: http://www.tradeeasy.com/photo/selle...logo/U-301.pdf (Only cost £27)

Took a few hours to fit as an A4 is not the easiest of cars to get rear bumper off but got there in the end. There is a honeycomb backing to the bumper but there was enough of a gap to slide the antenna strip between. I was a bit worried that cars bulb failure system would be an issue but appears fine.

The sensor only works at close range compared to the ultrasonic ones but for my use its no problem that it doesn't beep until you're within a couple of feet of an obstacle. Tried it with wood, metal, plastic and a person and all were detected although the final continuous beeb doesn't activate until you're just a couple of inches away.

A great buy for £27 and no cutting involved. Would definitely recommend.
CAVEAT - SEE POST BELOW AFTER FURTHER TESTS

Cheers

[sportq]

Those actually look pretty decent. Did you install into a saloon, avant or cabrio?

I've got an avant and I'm trying to recall where the reversing light is on it, it's not in the tailgate is it? Maybe it's possible to tap into the reversing light power somewhere else in the rear otherwise it's going to be a pain routing the cable back out through the tailgate.

Great find though!

Pete

[randall977]

I fitted one and found it to be fairly useless. It is quite a job to get an A4 bumper off but I was keen to avoid holes. The problem I found was that a electromagnetic strip sensor only works when the car is moving, does not accurately pick up objects and tends to beep when there's nothing there. It technically works...but not very well. To begin with you think it's good then after a few days you realise why manufacturers don't use this cheaper and easier method. In the end I fitted OEM sensors which involved a new bumper etc but it works and looks great.

[Ryggwelter]

Those actually look pretty decent. Did you install into a saloon, avant or cabrio?

I've got an avant and I'm trying to recall where the reversing light is on it, it's not in the tailgate is it? Maybe it's possible to tap into the reversing light power somewhere else in the rear otherwise it's going to be a pain routing the cable back out through the tailgate.

Great find though!

Pete

Hi Pete,

I've got an Avant too - the reversing light is in the body, not the tailgate so the wiring is easy. I tapped in to the harness behind the rear speaker amp/sub box on the offside. The biggest pain is dismantling half of the interior to get to the bumper fixings - broke one of the clips in the process.
The adverts say most bumpers are only held on with 2 of 4 screws - I counted 20 on the Audi to remove the bumper and another 20 plus to get to those screws plus a dozen clips.

[Ryggwelter]

I fitted one and found it to be fairly useless. It is quite a job to get an A4 bumper off but I was keen to avoid holes. The problem I found was that a electromagnetic strip sensor only works when the car is moving, does not accurately pick up objects and tends to beep when there's nothing there. It technically works...but not very well. To begin with you think it's good then after a few days you realise why manufacturers don't use this cheaper and easier method. In the end I fitted OEM sensors which involved a new bumper etc but it works and looks great.

Its still early days for me and I've only tested the car in the garage but it detected all the objects I put behind it and I never hit the workbench - will have to see how well it performs in the real world.

You're absolutely right, it only detects changes so once the car stops moving, the beeps stop. I figure the system will be an improvement on my previous 'have a guess' parking method and I don't want to fit ultrasonics so it was worth a punt.

I will post again in a week or two when its had some proper testing - looks like its going to rain lots this weekend too so that will be interesting.

[Ryggwelter]

OK - its now been about 3 weeks and as promised here's an update..

The very next day the parking sensors stopped working - wouldn't detect me even when I walked upto and into the bumper. They would work though if I opened the tailgate, so they hadn't 'broken', just gone very insensitive.
Not sure why this was the case - I had tested them previously with the tailgate down. Maybe putting the rear speaker back in had upset them (can't remember if it was in during previous test) or maybe it was due to the car being wet from the rain?

Did a bit more research on the Parking Dynamics website and found lots of guides and tips including installing two antenna's to help increase the range and stop the sensors being interfered with by the car itself (tailgate?). So I installed a second antenna in the bumper about 4" below the original (risk now of detecting the road) and I re-sited the main unit further away from the speaker & tailgate and improved the grounding.

It has definitely improved the system - it now works in the rain but does sometime beep when there is nothing behind - detecting the road.

In conclusion, they are OK if used with caution - they are variable so don't fit them to the wife's car to stop her reversing into stuff - you'll just get told "It didn't beep" or "it beeps all the time". I can understand totally where randall977 is coming from, but I will be keeping my electromagnetic sensor rather than replacing or drilling the bumper (I don't like the appearance)

Finally, just to reiterate, the system I have is a cheap Chinese copy, not the original Parking Dynamics version. If anyone has experience of the PD system I'd be interested to know how you got on.

Hope the waffle has been of use

[Brian566]

Hi
I have just posted a question about the Parking Dynamic as I also do want the holes in the bumper

Just a bit concerned about the gap between the metal and the outer plastic on the 8P A3 sportback

They have 40% off so is a good price and seems impressive

[0AlphaOmeg]

Its still early days for me and I've only tested the car in the garage but it detected all the objects I put behind it and I never hit the workbench - will have to see how well it performs in the real world.

You're absolutely right, it only detects changes so once the car stops moving, the beeps stop. I figure the system will be an improvement on my previous 'have a guess' parking method and I don't want to fit ultrasonics so it was worth a punt.

I will post again in a week or two when its had some proper testing - looks like its going to rain lots this weekend too so that will be interesting.

Interesting to read your experience. I've just been looking at this type of sensor, clearly another case of, if it's too good to be true... Shame as it's quite cool

BTW, tips for setting a reverse distance in a garage etc.

• the old "suspend a sock with a tennis ball in it" to contact your rear window (need to be able to see it)
• fit a baton to the floor (don't puncture your floor membrane), works really well, works outside too (raised paving/features) and can be set to work with front or rear wheels (i.e. use it for front wheels when reversing over it - lines your car wheels up nicely too ). And you can alter your paving to create the "stop".
• fit your electromagnetic parking sensor to your bench and equip it with a lamp Stops you walking into the bench in the dark

What speed do you need to be travelling at to trigger it?

Regards

[M1tchy]

I fitted this type of parking sensor into my wife's Astra many years ago. They were fine in theory but no where near as good as radar based sensors. Their main fault is they would see rain as an object and trigger. This also included water on the cars paintwork etc.


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