Over height vehicle detection.

[bernardgreen]

Following another impact from an vehicle on my thatched roof I am planning counter measures.

As part of these counter measures I need to detect oversize vehicles approaching the junction involved.

A through beam sensor would be ideal. I have permission to fit a module on the house on the other side of the road but to get power to it would be a problem. A battery powered TX is a possibility but will require frequent battery changing.

A passive reflector on that house would work BUT some high vehicles will reflect enough IR to make the beam receiver believe it can still see the reflector on the house. So those vehicles will pass un-detected.

The distance measuring devices similar to those used by surveyors and estate agents would be ideal if there was way to read the distance into a micro-processor. If it reads 11.9 metres it is the house with no vehicle in the beam. If less than 8 metres then it is a vehicle.

Other than a £ 700 device with an analogue output of the measured distance I haven't been able to find one suitable.

 

[EightyTwo]

The batteries in a beam transmitter usually need changing twice a year. Why not do it when you change your clocks?

 

[Europlex]

Get your Council/Highways Dept to fit one of these, seen them work - and they do. - Top of the list.

Good luck.

http://www.furnitubes.com/bollards/bell-bollards

 

[Europlex]

P.S.

What are you going to do at silly-o-clock when a lorry breaks your beam?

My wife has visions of you running outside naked as the day you were born, that'll stop anything.

 

[bernardgreen]

Thanks Europlex.

I have sent the video URL to the council's Highway Asset Manager prior to a meeting with him in the first or second week of September. Installing bollards is probably the only 100 % effective means of protecting my cottage roof.

But nothing is simple. The footpath is very narrow and any bollard in the most effective position will force prams and wheel chairs off the foot path and into the road.

Also there is an 11kV cable under the foot path and this may prevent a deep enough foundation being installed. The cable is not very deep as was discovered during recent road works.

Eighty Two

I have found a couple of battery powered emitters with ( claimed ) 100 and 150 day battery life. But these only transmit a pulse every second and the receiver has to miss 3 pulses before it indicates detection. At 15 MPH a 20 foot long vehicle takes less than a second to pass the sensor so could be missed.

 

[bernardgreen]

My wife has visions of you running outside naked as the day you were born, that'll stop anything.

Sorry to disappoint the good lady but that is un-likely.

The first defence at night will be warning beacons activated by the broken beam, these will be a close to the over hang as possible with being a fire risk to the thatch. Second is video to capture any hit and runs.

PS how does the missus know I don't wear anything in bed.

 

[Europlex]

PS how does the missus know I don't wear anything in bed.

She has her spies, I seem to remember her saying this sort of thing about others"

Thinking about it, I must ask how she knows so much about so many men!

 

[SimonH2]

Does the impact happen over "the highway" or over your land ? I'm guessing your roof overhangs the pavement and it's large vehicles taking the corner too tight that are catching it ?

Can you hang something "suitably heavy and non-destructable" just clear of your roof so that the loud thud (and possibly bits of wagon falling past the windscreen) will alert the driver

 

[EightyTwo]

I can't remember the make of battery beam we used and I'm on holiday in Spain at the moment! I'll try and remember to find out when I get back. It looked a bit like a double Takex beam and took six C cells per side. We used them on a long driveway to a farm house, in combination with a radio door contact transmitter, to trigger a paging system.

 

[bernardgreen]

The impacts are the sides of long lorries that cannot make the turn to the right without the vehicle going over the pavement. If they are seen they are told to back off and turn left which is possbile without hitting any buildings.

The previous owner had fitted a spike intended to damage vehicles. Some of the fixings were pulled out of the wall after a hit. The vehicle was never identified. I cannot do that as it would be illegal, criminal damage. A solid steel fend off that pushed the lorry away from the roof would be acceptable as it would at worst dent the vehicle. But it would need to be "streamlined" so as not to jam on the vehicle. If it jammed and the vehicle pulled it off the wall there would be damage to the stone wall. This streamlining would make it quite large and a bit of an eyesore.

One option is a large old lamp which a picture proves was there in the distant past. The conservation officer could not object. Replicated out of plastic it would be visible in the day. Could not be lit as it would be too close to the thatch and be a fire risk if it was ever damaged.

 

[EightyTwo]

Could you not use LED strip lights? 12V and an amp or two are hardly likely to cause a fire, especially if you use fat wire and a thin fuse! There are miles of them on fleabay - all colours and lengths with waterproof covering. Some even change colour...

 

[bernardgreen]

The insurance company lay down some very strongly worded conditions. Nothing electrical other than pyro cables within one metre of the under side of the roof ( this is the dry and most easily ignited area ).

Vehicles with lit lamps at roof level are a fire hazard if the lamp shatters when it hits the roof and is embedded in the thatch.

 

[SimonH2]

Sound slike you need, in addition to whatever you manage to come up with for your OP, some CCTV to catch hit & run offenders.

 

[SimonH2]

Another thought ...
Can you setup a beam (with passive reflector) at an angle ? A shiny vehicle would be unlikely to reflect a significant amount of IR back towards the emitter if it's not perpendicular to it's side.

Or alternatively, could you add a reflective detector ? An emitter and receiver at angles so that a passing vehicle would be likely to reflect some of the energy back to the receiver. Without a vehicle present, the energy just naffs off across the road.

 

[SimonH2]

Or going old-school, but requiring "manual reset". How about a thin rope or wire across the road with a weak link. Vehicle pulls and breaks the link which can either activate a switch (like the safety rope systems used on machinery), or just trigger a manual flag or fireworks in front of the driver.