Laser Height Detection System

[iowasnowbird]

I'm the DN (designated naGivator) and that is my job. I know we have to have 13'6" to clear so I'm always vigilant. No problems so far.

[Stripe34]

Originally Posted by Hit_the_Rhod

My system is to find a truck that is 6" taller than my coach and only drive where he drives first! When I see the top of the truck peel back, I know it's time to find another truck, AND another route!

LOL love this!

As far as campgrounds and low wires go, you could rig a removable pole on your toad and have it driven ahead once you get off the superslab. $30/hr and all the *diet* Dr Pepper I can drink :-)

[idoxlr8]

We run a laser for ride height measurement on our race car, works very well. It's also setup to help avoid excessive wheel stands. They are at least $1k for the laser, then you'll need something to display the measurement in the coach. As others have mentioned, you'd need to have this on the front and drive under slowly to get a measurement. Not too practical really, you could get out and look just as easily.

[georgelesley]

It sound really inconvenient and have to date never used it and hope never will, but I still carry a laser measure to stick under any obstacle I have doubt about. I have heard truckers carry a stick and I have thought about a folding tent pole and found one on eBay long enough but have not bought it and probably never will. Experience and the truckers road atlas have been great teachers.

[AtomicRT]

I'm thinking of flying a drone set to fly a 1/4-mile ahead of my rig and at the height of my trailer (this technology already exists and is inexpensive). If it crashes into a bridge, I have a 1/4-mile to stop. Battery life may be limiting.

[knightstorm]

Put one of these on the vehicle in front of you.

http://giraffeg4.com/

[KSagal]

Originally Posted by knightstorm

Put one of these on the vehicle in front of you.

Collision Alert & Overhead Protection System by GiraffeG4

That would work for a tractor trailer, where the trailer is taller than the tractor. It would work for a 5th wheel where the trailer is taller than the tow vehicle.

It would not work as well on a class A like mine. (the top of my cab at the top of the windshield is lower than the top of AC units, but still, a tough measure at that point.)

I suppose you could mount it on a bracket over the top of your windshield, like on a sun shade that I have seen on trucks, but that is only bringing it a few inches forward, and is still likely behind your front bumper.

If you need to stop and creep under the overpass slow enough for this to be of value, I would think the sized tent pole might work just as well.



Another issue that does concern me sometimes especially when the clearance is very tight, is either the slope of the arched bridge, or even if the road dips below the bridge so that the vehicle is not parallel with the bridge.

I have seen where there is a slight down slope so the front of the vehicle fits, but as the front wheels start to climb out the incline of the far side, and the back of the vehicle is still under the span, the relative height of the vehicle raises compared to a singular post or measure point.

Mostly, so far, I give myself lots of room. Eventually, the technology of either the measuring devices, or the GPS databases will get even better than the holes in the current technology.

[Stripe34]

Originally Posted by knightstorm

Put one of these on the vehicle in front of you.

Collision Alert & Overhead Protection System by GiraffeG4

Huh, so it exists and is on sale for $199.95.
Protect Your RV from Overhead Damage

But for a class A you'd have to send the toad ahead to measure, I guess.

If we ever move to a 5er I might consider something like that.

Good find.

[vincee]

I would think a system to alert on heights would be in comparison in usefulness to depth finders on boats. There are charts and navigation aides for the waterways you are boating in but boy you can't beat a good depth finder to know how deep the water is where you are boating. Think fisherman too on how they depend on them.

[azpete]

quote "looks like an expensive fix for a problem that doesnt exist"
that means every rv'er has to have one. there are many thing on the market already
that serve no useful purpose, but as seen on tv sells millions of dollars of them every day. but wait, you may be able to get two, just pay separate shipping and handling.
realistically, it could be made to work, but at what cost, and what accuracy?

[Hgrace56]

Doesn't have to pull under the bridge kind if defeat the while purpose?
I mean what then? Back out?
My Rand McNally Tab 8 hasn't steered me to any low overpass.
In fact there are local streets that give me low tree warnings.
And users can comment or add to the database.

[VanDiemen23]

To make a height warning system practical it has to have sufficient range to give a warning with sufficient time to stop. Figure it has to work at 40mph and below. Roads with speeds posted above 40 most of the overhead issues are taken care of. Maybe a range of 200-300ft to cover reaction time, recognition of the obstacle, and braking. The kinds of motion sensors found in your cell phone are in a lot of electronics nowadays and can be used for motion compensation (mocomp as we call it is used in almost every dynamic sensing application) so the coach moving and bouncing isn't that big of a problem.

There will be a lot of false alarms, primarily because of branches and in the case of bridges, the common dip prior to the bridge on back roads. That's not all bad, although it might drive you nuts on back roads with a canopy. It would definitely need adjustable warning heights and alarms.

Radar will work for structure but would be less reliable on foliage and likely unworkable to find wires - depends on wavelength and if you could make circular polarization work for this application.

LIDAR is still a bit expensive but will come down in price significantly as self driving vehicles mature. MonteHP's idea is exactly how a LIDAR works.

Laser ride height sensors used on race cars are designed for very short distances and operate as a simplistic near-point LIDAR. Increasing the range creates an aiming problem, which requires a scanning mirror approach to create first a line, and then scanning the line across another angle, creating a search volume. Again, that's what a full-blown LIDAR does. Once you have what's called a "point cloud" of individual range measurements you have to turn that into a 3D model of the environment and then make the warning decisions off of that. This is usually done at 10-60 times/sec. This requires a significant amount of processing power and speed. The longer the range, the more stuff you find and have to process.

The Giraffe thing is ultrasonic and essentially only works if you recognize the obstacle, stop, and crawl, and it helps if the emitter is directly under the lowest spot. It seems to me to be pretty useless.

Self-driving trucks will rely on this plus a gps map of all known obstacles, sort of like how radar detectors "find" red light cameras. At that point you'll be able to buy a stand-alone device.

[KSagal]

I believe this thread is overlooking the logging into the GPS database.

Most roads are already logged into the database, and I believe in relatively short time, clearances (At least official clearances) will be added to the database, if there is a demand.

Then, sensing for structures will not need to be done on the fly. This will work for all bridges and other types of overpasses.

As far as branches and wires, that is a different story. The GPS databases will not ever be current enough for these.

[1doodadd]

Stripe34, You got a Blue Heeler??