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harry.m1byt

Caravan Levelling Aid Mk Ii

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Caravan Leveller Mk II
Here is my second attempt at making a caravan leveller – the MK II. The idea was to incorporate some changes to make the sensor easier to calibrate, so I built a completely separate pair of units – the bob weight sensor and the display. The circuit is identical to my earlier version. The only real difference is that this is a bit smaller, and instead of calibrating via the contact screws, which was a little awkward, this one is calibrated via adjusting the nuts supporting the baseplate, the PCB material.


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Old cassette tape case, used as the case for the display. It is permanently powered, ready to use, so a switch is included in the side of the display unit. Build method is my usual quick and dirty for a one off design – just solder the components and wires in place. Case contains 4x superbright white LED’s for the four directions, 1 superbright red LED as both a power on indicator and a reference point when working in absolute darkness setting up, a switch for turning it on and off and a diode to protect against the power being connected the wrong way around.



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Intention is to (like the Mk I) hang the display in the front window or just place it so it can be seen only whilst setting up. The damp patches are where I superglued the LED’s in place.



2_zps733d0f79.jpg

The new sensor uses a length of 20mm plastic electrical conduit, with a coupling with a threaded lug end and a threaded locking ring. The latter secures it to a sheet of double sided PCB, that PCB is then fixed to a second sheet of PCB, with 4x4mm brass screws and three 4mm brass nuts per screw (12 nuts in total), so the spacing between the boards can be micro adjusted at each side for calibration purposes. Total height of the 20mm conduit from face of PCB to the top is 6. 5”. Once the screws were tightened, I ground their heads down to reduce the amount they protruded.



Linking the display to the sensor unit, I used 4 pair (8 wires) flexible type network cable, but only 6 wires are needed. The network cable is fixed to the lower PCB only, with a couple of tiewraps, holding it clear of the underside of the end of the conduit and its locking ring. A 5amp two way connector is fixed to the lower left corner for connection of the 12v +ve and -ve, with a third tiewrap


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The upper PCB has its corner cut off, to enable access to the 12v input terminals. Here are both units ready for final connection.


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This is the brass bob-weight, turned up in the lathe. The RH end was drilled and tapped to accept a 4mm brass screw. The brass screw I drilled through the centre with a 1mm drill, to accept a suspension wire. I made a second similar screw, which screws into a tapped brass insert which was itself turned to fit neatly inside a 20mm plastic bush (the black object on the right). You can just see the brass insert poking out of the plastic bush.



The suspension of the bob-weight is crucial to its accurate operation. It has to be centred, both top and bottom and the suspension wire needs to be conductive, thin and very compliant, so as not to disturb the ‘hang’ of the bob-weight. Network cable is too rigid and will want resume its curl. I used a single core from the telephone wire, as used to link a phone to the socket at the wall. This type of wire has the copper strands mixed in with nylon, which makes it very strong, but very flexible. The downside is that it is very difficult to solder, but not impossible. That is stripped at either end, then passed through the 1mm holes in each screw head, then the ends soldered at the far end of the screw from the end (the threaded end). I set it up so the length of the suspension wire, hung the bob-weight with 2/3rds below the contacts, 1/3 above the contacts.


5_zps69b879df.jpg

Here are the details of the contacts. I initially tried pop rivets as contact points and found they were not as good as brass, then there was the difficulty of connecting to them (hence the unused hole in the coupling). Then I searched for some brass grub screws with a slightly domed contact end and found 4x in an old scrap 13amp socket so I repurposed them as contacts. To connect the grub screws to my four cables, I used the guts from 4x 15amp connectors (chocolate blocks).


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schematic.png
Wiring Diagram and components.
Circuit.png




How it works and how to use it


You mount the sensor part of the unit, where ever it will fit - under a bunk, in a top cupboard etc. , but it must be protected from other items which might knock it out of calibration and the base needs to be stuck down with double sided thick tape, but keep in mind it will need a 12v supply.



The umbilical cable linking the sensor unit to the display, must be long enough to allow the display to be hung or placed in a front window, where it can be easily seen. Mine is mounted in a top cupboard at the front of the van.


Calibration - Set the van up perfectly level with a spirit level, though it may then need some minor adjustment to ensure the drains work. The inaccessible 4mm fixing screw at the rear is intended to tightened up and not moved again, the other three screws and nuts allow you to make adjustments for calibration purposes.



The grub screws should have been previously set to just allow the bob-weight some slight movement between them - the bob-weight should be loose enough to allow it to rattle between the contacts when tapped very lightly.


The 4 contact wires should be connected so as to light the LED which matches the higher side. LIT = that side or end is too high.


The 4mm nuts are adjusted so that the pairs of LED's (L & R and F & Back) both flash on for an equal period of time. Once both pairs are flashing equally, the 4mm lock-nuts can be tightened down.


In use, you just simply drive onto a pitch and get it to show level for side to side, then unhitch. You then adjust the end to end level with the jockey wheel. The display is as easy to read in the absolute dark as in the daylight through your interior mirror. It is very precise, providing you get each pair showing the LED's lit for an equal amount of time. If it stops flashing, just give the side of the van a very gentle tap with a finger tip. It would seem to be accurate to around 1 degree, much more than is needed.

Edited by harry.m1byt

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This model, like the Mk1, would not suit me at all.

A snap on / off (level / not level) is really impractical for most caravanners who will very rarely be able to achieve absolute level conditions and so would probably have at least 1 led permanently displayed (very frustrating!).

 

It might be more acceptable to have each plane graduated using traffic light leds at each of the 4 compas points - but that is still likely to have some leds permanently lit.

 

The tried and trusted "bubble" type display allows acceptance of "as-near-as-you-can-get-it" without the frustration (irritation) of a red led continually displaying your failure.

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Pete, you must know our apprentice at work.

He is under the impression that if the bubble is between the lines then its level. He won't use his stanley level as the bubble is the same width as the lines and that takes too much effort.

 

Harry, we have had issues at work with network cable snapping at joints when its been in a mobile environment. Keep your eyes open for an alarm enginneer at work and ask for a offcut or two.

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This model, like the Mk1, would not suit me at all.

A snap on / off (level / not level) is really impractical for most caravanners who will very rarely be able to achieve absolute level conditions and so would probably have at least 1 led permanently displayed (very frustrating!).

 

It might be more acceptable to have each plane graduated using traffic light leds at each of the 4 compas points - but that is still likely to have some leds permanently lit.

 

The tried and trusted "bubble" type display allows acceptance of "as-near-as-you-can-get-it" without the frustration (irritation) of a red led continually displaying your failure.

 

I think you are misunderstanding how it works. The red LED only indicates that it has power and serves as a reference point so you know which other LED's are lit in the dark. It is lit while ever the unit has power.

 

It does show how far out of level the van is, but it needs some interpretation. If you start with the front very high, the FRONT LED will light up constantly, as you adjust it with the jockey wheel down, the bob-weight will begin to bounce on the contacts and FRONT plus REAR LED's will begin to flash, with the FRONT flash staying lit for the longest period. As it progressively gets nearer to level, the two LED's will flash more and more for an equal time. Once perfectly level they flash for a perfectly even period of time.

 

It is almost impossible to get it to turn both opposing LED's out at the same time, so the bob-weight hangs clear of both contacts, because it is so very sensitive, so your aiming point is to just get the two opposing LED's flashing for an equal period of time.

 

So just like a bubble level, you can use it to set the van up to varying degrees of level - but it is so easy to get it spot on using this, why not get it spot on?

 

You can buy two types of network cable, the stranded and solid cored. I suggested above using stranded. Stranded is the very flexible type used to link a PC to the network socket on the wall. 3 pair stranded alarm cable would probably be better, I just didn't have any to hand.

Edited by harry.m1byt

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Don't be put of by negative posts I think its great that we have members like yourself on this forum who are willing to share their ideas with us for nothing.

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A glass of water on the cooker top is much simpler. (or in the front window)

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A glass of water on the cooker top is much simpler. (or in the front window)

Nope red wine for me I can see it easier from a distance as long as the OH doesn't drink it first.

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Don't be put of by negative posts I think its great that we have members like yourself on this forum who are willing to share their ideas with us for nothing.

I agree, making stuff that is useful is a dying art, you and other inventors should be encouraged.

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A glass of water on the cooker top is much simpler. (or in the front window)

 

My leveller works in the dark, will not spill, it is much more accurate and much more convenient quicker to use.

 

Besides, a certain other party saw sufficient merit in such a leveller to go into commercial production with one.

Edited by harry.m1byt

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Don't be put of by negative posts I think its great that we have members like yourself on this forum who are willing to share their ideas with us for nothing.

 

Not so fast thomasoes!

My comments were not negative, they were constructive input and OP responded to clarify.

I am also a contributing member of this forum (if you check in the advice section I have contibuted a subject entitled installing underfloor heating). It recieved several comments and questions (some of which I suspect you may have considered negative - but I didn't) to which I responded with clarification - just has OP has done here with me.

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Great idea and I love the prototype. Very interesting and, to a certain degree, inspiring. Some thoughts for a potential MkIII:

  • Love the concept of an accurate electronic levelling aid. Whole concept appeals to me.
  • Love the use at night
  • Consider an electronic gauge rather than a binary on/off display. Something like the front light on KITT with maybe 12 LEDs, the 6 outermost indicating red, then amber and the two inner showing green for level – in a cross shape. See image.

tn_gallery_63455_1385_9720.jpg

  • Add two audible tones with a 50% mark/space, one high that reduces, one low that increases. When they [audibly] meet, you’re level.
  • These two allow for night time use and for when you want the gadget inside (e. g. the shower floor) but need to be outside to adjust
  • You would need to use strain sensors with a bob weight rather than a binary on/off

 

Or just use your smartphone. .. ;)

 

tn_gallery_63455_1385_357494.png

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Not so fast thomasoes!

My comments were not negative, they were constructive input and OP responded to clarify.

I am also a contributing member of this forum (if you check in the advice section I have contibuted a subject entitled installing underfloor heating). It recieved several comments and questions (some of which I suspect you may have considered negative - but I didn't) to which I responded with clarification - just has OP has done here with me.

 

I didn't read it as negative, just a misunderstanding of its principle of operation and a desire for it to supply more information.

 

Without considerable design and development work, I cannot extend its mode of operation and I'm sure its accuracy would suffer in the process. As my design is, providing you calibrate it accurately for your desired version of level and providing you understand the principle of it operation, you can reproduce that level to a high degree of accuracy and extremely quickly.

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Great idea and I love the prototype. Very interesting and, to a certain degree, inspiring. Some thoughts for a potential MkIII:

  • Love the concept of an accurate electronic levelling aid. Whole concept appeals to me.
  • Love the use at night
  • Consider an electronic gauge rather than a binary on/off display. Something like the front light on KITT with maybe 12 LEDs, the 6 outermost indicating red, then amber and the two inner showing green for level – in a cross shape. See image.

tn_gallery_63455_1385_9720.jpg

  • Add two audible tones with a 50% mark/space, one high that reduces, one low that increases. When they [audibly] meet, you’re level.
  • These two allow for night time use and for when you want the gadget inside (e. g. the shower floor) but need to be outside to adjust
  • You would need to use strain sensors with a bob weight rather than a binary on/off

 

Or just use your smartphone. .. ;)

 

tn_gallery_63455_1385_357494.png

 

As already said, adding more indication of the amount it is out of level would need considerable development work. Yes I can do that, but I would not even recover the cost of the development work. In addition, you guys would not be able to reproduce it on your your workbench at home.

 

What I have designed is something simple, cheap and easy for you guys to reproduce at home.

 

the only thing which seems to be causing confusion, is how the display works in practice in demonstrating how far out of level it is, but work it does. Constant steady light, that side is way too high. As it becomes more level the weight will begin to bounce between the two contacts and the lights flicker between the two. when both lights stay on for equal amounts of time as the bob bounces - it is at level.

 

An Ipod type level would be ideal, but you cannot see it outside the van in the dark. I would need to put on my reading glasses to even see it. I can see my flashing lights without needing the glasses, nor having to venture inside to check it. So the Ipod would need you to be constantly going from adjusting the level, to checking the Ipod. My device lets you do it all it one simple operation from outside and at the front. The only way I can think of to make your Ipod work in a similar way to my gadget, would be to add a camera watching the Ipod and a TV monitor visible through a window.

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Hi Harry,

I always thought your idea was simple, effective and cheap, I'm glad to see you have carried on with your to work despite some of the comments received. Just one point, I see no reason for the 4 x 100 ohm resistors and the 1n4001 diode, you could reduce the component count!

 

Others have suggested a more analogue display, frankly I don't see the point, just how level does the caravan need to be?

 

Well done that man!

 

J

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Maybe a smartphone holder with a sucker attachment so that it can be simply mounted by pushing it onto the side of the 'van. Then it can be used anywhere you are making the adjustments :) Very simple to manufacure and solves a problem for caravanners at a minimal cost (app + mount).

 

sml_gallery_63455_1385_18053.jpg

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Whilst I commend the op for all of his hard work on getting his thingumygadget to work, and, it's nice to see that people are prepared to go to great lengths to solve a problem.

 

Eyeballs do it for me, as long as the sink drains, that's as far as I need levelling :ph34r:

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Eyeballs do it for me, as long as the sink drains, that's as far as I need levelling :ph34r:

 

What if, God forbid, a pencil were to roll-off a work surface due to your cavalier attitude to levelling! You should be ashamed of yourself, blindsider. ..

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Hi Harry,

I always thought your idea was simple, effective and cheap, I'm glad to see you have carried on with your to work despite some of the comments received. Just one point, I see no reason for the 4 x 100 ohm resistors and the 1n4001 diode, you could reduce the component count!

 

Others have suggested a more analogue display, frankly I don't see the point, just how level does the caravan need to be?

 

Well done that man!

 

J

 

Thanks for the vote of confidence, as said it needs to be used, to appreciate just how simple it is and how well it performs.

 

The resistors in the supply lead, avoid the need for a fuse - I always use series resistor in such low current items, rather than fuses, to limit short circuit current. The diode prevents the LED's being blown in the event of it being connected with reversed polarity.

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Maybe a smartphone holder with a sucker attachment so that it can be simply mounted by pushing it onto the side of the 'van. Then it can be used anywhere you are making the adjustments :) Very simple to manufacure and solves a problem for caravanners at a minimal cost (app + mount).

 

sml_gallery_63455_1385_18053.jpg

 

That is better, but still not quite there. If you were to mount it outside, it would need a proper rigid bracket, with some means to calibrate it to your preferred level. You then have to boot up the Ipod to the level app and you have to obviously buy an Ipod.

 

Whereas, once I have expended my time making my own gadget, I just flick a switch, it works and is dedicated to the one single job of levelling the van.

Edited by harry.m1byt

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Whilst I commend the op for all of his hard work on getting his thingumygadget to work, and, it's nice to see that people are prepared to go to great lengths to solve a problem.

 

Eyeballs do it for me, as long as the sink drains, that's as far as I need levelling :ph34r:

 

Good grief, I would spend the night constantly falling out of bed ;)

 

I don't know what my own personal tolerance is for level, but it has to be fairly close, to be acceptable. I notice straight away when I have to walk uphill to the bathroom.

 

In the early days I would use one of those three cornered levels, set just inside the door, then pack it with cardboard to get it to show level when it was level and after then making the minor adjustments for drainage. I never found the three cornered one accurately able to reproduce a level, even one set.

 

It was the constant aggravation of levelling it then still having to make more fine adjustments, which prompted me to try to make something better.

 

One idea I briefly considered, was a small hook on the ceiling, a length of string and a plum-bob. Mark a target point on the floor and your ideal level will always be reproduced and very accurately. Trouble is, it would swing endlessly and would need some damping and someone inside to watch it. I wanted something I could use to set up quickly level on my own.

Edited by harry.m1byt

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I find the topic interesting, and am tempted to have a go at producing something similar for the fun of it . . (now there is a guiding light), but as blindsider says, eyeball is good enough for me, and if the sink drains, that is a bonus . . maybe some years spent at sea with the boat on its beam-ends have reduced my intolerance to varying angles . .

 

cheers

Edited by Mr Nobody

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I used to shoot Air Rifle Field Target and one of the things

I was asked to try was an electronic device for ensuring the

rifle was held square, i. e. not tilted L or R, it was very sensitive

and frankly annoying but the lot of it was, with a reedy buzzer and

a couple of l. e. d's, in a case the size of a AAA battery.

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Levelling a caravan is about to become an easy onr person process, no hassle, visible in the dark and in sunlight. A level indicator of some description will be standard in the future.

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Now all we need is for the manufacturers to make caravans where the shower & the sink drain when level.

 

Ok maybe that idea is a bit far fetched :lol:

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Nah. We need a little jack under the appropriate corner and a remote control in the 'van. Just to tip it from absolutely, unquestionable, totally level to a bit of an angle which shoots the water down the plug hole! ;)

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