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Getunderit

Working Lift Bridge Diorama

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I am new to modelling, but not new to being creative. My background, as a young lad, was diesel mechanic, welder, and avionics (RAAF). Past 20 years has been in counselling (no hand skills required). Then, out of the blue, I got roped into, by the local maritime museum, to convert an antiquated lift-span bridge console to operate a model bridge. Then I discovered that they had no model bridge and nobody to build one. Then I found out that the museum is totally run by volunteers. So I end up volunteering to build a model bridge which can be operated by the real bridge's original console (1964-1995), and have the bridge set in a diorama display of 2400 x 1200 mm (8 x 4 feet). Yes, I have to build the diorama too.

 

I have been doing this for several months now. I am still a long way from completion. My plan here is to post photos of progress by piecemeal.

 

Both the console and bridge lack available schematic diagrams and drawn plans. So the whole modelling aspect will have to be scratch-built. As a result, I had to extrapolate the bridge measurements from numerous photographs, reverse engineer the console, and figure out how to operate the bridge. The current bridge operator was not allowed to tell how to operate the bridge, but was able to tell me what each switch did. From this information it took me a while to figure out the operating sequence. It is not a simply matter of raising and lowering the lift-span. There is much to consider in terms of safety, and in controlling the foot, road, and vessel traffic even before raising the bridge.

 

Anyway, the first few months was spent in compiling the information needed. Then draw up plans (bridge) and schematic diagrams (electronics) for myself to follow. Actually I still have some unfinished problems to solve. The whole bridge fits nicely within the 8 foot width using a 1/72 scale.

 

Here is a photo of the actual bridge:

 

 JLxBTXh.jpg

 

The console as it arrived at the museum:

 

ZvGofFM.jpg

 

Proposed display layout:

 

wR8ixv8.png

Yes, there will be a model boat traversing under the raised bridge-span.

 

t2Midol.png

It is hoped that the museum display will be interactive by the visitors (mature or not). Meaning, that the display operations need to be, as far as possible, child-proof. The last thing the museum wants is someone purposefully lowering the bridge on the traversing boat :o. Or any other possible out-of-sequence operations. This has become a major headache for me.

 

Finally, as an introduction, the museum is a non-profit organisation, so it has limited funding. My task then is to build this display as cheap, yet in good quality, as possible. So please excuse my choices of materials to do the task. Both the museum curator and president as given my free rein to do this project, which is great, because I work best without a boss.

 

Though this project seemed daunting to me, I had also found it very satisfying to see it progress along.

Hope you will also enjoy watching this work in progress.

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Stating the obvious, but that's one huge diorama! I wish you all the very best with this charitable project.

 

I'm sure you'll get a lot of help from BM members should you request advice or help with materials, electrical and mechanical issues!

 

Just a couple of questions.... One, will you be building it in sections elsewhere and only assembling it on site when it's all finished?

                                          Two, how long are you giving yourself to finish it?

 

 

Rearguards,

Badder

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Wow, what a project.

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1 hour ago, Badder said:

.... One, will you be building it in sections elsewhere and only assembling it on site when it's all finished?

     Two, how long are you giving yourself to finish it?

One: Yes, the museum workshop does not have the space to include this display area in its already cramped area. The curator is always moving the displays around and replacing others with new ones (donated models and actual naval and maritime bits). The new models have to be sealed in a perspex case (glass is no longer allowed). The bridge display table and its control box (under the table) are separate sections. Both are being built, in my lounge room (I have no garage). Future photographs will reveal this.

 

Two: After discussing with the museum president on how much time I will allocate to the task (hours per week) he accepted that it will take more than a year. However, their is no time limit. The only requirement is that it will work and it will look good. My main focus is that it will look good enough to stand on its own. Meaning, that one day the working parts will cease to do its job, and nobody will want to repair it or obtain parts. On that day the model can no longer rely on its working parts for its attraction. So it needs to look good enough to stand alone, and still be attractive, as a static display.

 

Last week I went riding (road cycling) with friends, and a newcomer joined us. He was in his late thirties. We were discussing the uses of PIC microcontrollers and the Raspberry Pi. He was very familiar with both, but I am new to these things and won't be using them in this project. I mentioned that the project will have certain sounds effects such as an alarm bell, steam whistle, and a diesel engine sound for the boat. He said how can you play WAV files without a PIC. I said, "Like they used to, with transistors and other bits". He did not understand how that could be. His statement brought it home to me that the future is more than likely to have people who will not be able to repair transistor and integrated based circuitry. Much like some technicians who cannot design valve (vacuum tube) circuitry.

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to continue:

 

Here is how I plan to use two geared (148:1) DC motors (donated) to drive both the bridge and boat.

 

fefFEYb.jpg

 

The motors are too big to be placed in the span hut like the real version. So both motors will be in a control box under the display table. The drive mechanism will be pulley-cable systems.

 

a4mzEdI.jpg

 

Here is a collage of several bridge plans. I used Microsoft standard Paint program for the drawings.

 

UQbW3E7.png

 

For those unfamiliar to the lift span bridge operation, here is an animated GIF.

 

PnBroES.gif

Edited by Getunderit

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19 minutes ago, Getunderit said:

I said, "Like they used to, with transistors and other bits". He did not understand how that could be. His statement brought it home to me that the future is more than likely to have people who will not be able to repair transistor and integrated based circuitry. Much like some technicians who cannot design valve (vacuum tube) circuitry.

:sad:

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Thank you Badder, Gorby, Rob1 and Vince1159 for the thumbs up.

 

The timber arrived to my place. Started straight away in marking out all the pieces, cutting them out, and then assembled to plan. All worked out well (surprisingly).

As you can see, I am working in my lounge room. The old dining table to the left is my workbench, the one on the right is my desk. It's were I sit while typing this post.

The split across the table is the 3 mm gap for the boat vane to glide along.

 

xy70pBE.jpg

 

Below is the construction of the Control Box. It has two doors for accessing the motors, cable system and electronics. Once built, it is stored in my spare bedroom until it is time to install its components.

 

qfqDpjr.jpg

Edited by Getunderit

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In at the deep end or what?

Most impressive, commitment and build wise.

 

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Wow that's a fantastic looking project Peter, and a Merry Christmas to you and your family.

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Are you all getting ready to celebrate the New Year?

I am going to watch our local fireworks close up this year. Lay back on the beach stretcher and watch it all explode above me :party:

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13 minutes ago, Getunderit said:

Are you all getting ready to celebrate the New Year?

I am going to watch our local fireworks close up this year. Lay back on the beach stretcher and watch it all explode above me :party:

It's going to be the same old, same old visit to Mrs. Gorby's sister's place. Not exactly exciting, but good food and good company (notice I put the food first?). It certainly wont involve any beaches, I don't really want 2018 to start with hypothermia. :cold:

Hope you have a good'un.

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The beginnings of building a bridge. The first thing I need to lay down is centre pins (2-3 mm bamboo skewers for doweling) for the footings and piers.

The footings were unavailable unless I bought 8 feet of 32 mm dia curtail rod (too expensive considering I only need about a foot). So I cut and filed them from a piece of scrap board.

Glued the footings in place.

 

tmhiqS0.jpg

 

Applied wood putty between footings and table top (water) so there won't be any shadow line. Otherwise the footings would appear to be on top of the water as opposed to going the the river bed.

Then I added the piers and bracing. Each set piers has its own length so a curvature of the bridge can be made.

a6wkewy.jpg

 

Then I added the girders. The centre pictures show were Bridge St. will go under the bridge.

ch4ypGX.jpg

 

To tell you the truth, the way it turned out, it felt good to build this.

Considering it is my first model, it showed promise. I started to feel more confident in accomplish the rest of the project.

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10 minutes ago, Gorby said:

It's going to be the same old, same old visit to Mrs. Gorby's sister's place. Not exactly exciting, but good food and good company (notice I put the food first?). It certainly wont involve any beaches, I don't really want 2018 to start with hypothermia. :cold:

Hope you have a good'un.

Thanks.

 

Gorby, I hope this year the company will improve to equal the cuisine. 

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Seems to be taking shape quite quickly, you're a pretty quick worker and it looks like your quite handy with carpentry.

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1 hour ago, Gorby said:

Seems to be taking shape quite quickly, you're a pretty quick worker and it looks like your quite handy with carpentry.

Sorry if you got the wrong impression. I did mention in my first post that I have been working on this project for several months. So what I am posting, for the time being, is posting in piecemeal what has already been done. I am doing it piecemeal because there are many photographs, and to post them all at once will, in my opinion, would be too much too soon to enjoy watching the process.

 

Regards to carpentry. I personally wish I was much better at it. I use old fashioned tools with a not so steady hand these days. Woodwork has never been my forte. It comes out okay, but on close inspection one can see it was not built be a qualified carpenter. However, thanks for the compliment.

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Painted the bridge and river area with a few coats of acrylic undercoat.

 

The holes you can see near the span location is for wiring the contact points where the span will dock onto the bridge. There will be eight contact points. These will provide power and data needed for the span electronics. Did not want to have wires hanging and moving from the span, so contact points were used. The span will have a 9 volt rechargeable battery, which gets recharged each time the span gets docked. In between then, the span needs power to determine when the span has reached the top of the tower, change the vessel traffic lights from red to green, maintain under span red and green navigational beacons, and have span hut interior lighting.

 

On the riverbank area you can see where Bridge St will be located.

 

6JjwX6M.jpg

 

On both lateral sides of the bridge are several Fender piers. The outer ones have navigational beacons on their centre piers. The outer / surrounding piers will be installed later, just before painting the water.

 

EbD4gFL.jpg

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Thank you Sgt.Squarehead for kind words.

 

to continue:

In my spare time, while waiting for parts to arrive, I started to cannibalize old computers, TV sets, disk drives, etc for parts.

The display will have some sound effects (alarm bell, boat engine, and maybe a fog horn). A set of good speakers from a TV set came in handy. However, I needed to make a bracket for them so their diaphragm would not touch anything when mounted, or the sound would get muffled.

 

a3SiAKf.jpg

 

I went to the museum to cut out holes in the console for the speakers and other connectors. There the museum president expressed the idea of displaying photographs of the console interior. Then I opened my big mouth and suggested to replace the front panel with a thick sheet of clear Perspex. So now the console has become another diorama, a wiring diorama.

 

As a result, the console interior needed to be cleaned up. Even painted. So I chose a darkish blue-grey in the hope of contracting against the coloured wiring. Also in contrast, the console exterior is to remain antiquated in appearance, just as it arrived to us, but somewhat cleaned up.

 

OLF5RUZ.jpg

 

exk7G08.jpg

 

 

 

Wishing you all a ....

n9c3BIx.gif

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This is really good stuff!

 

Going  to keep an eye on this one.

 

Happy new year.

 

Graham

 

 

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Thank you Graham, and folks who have given this thread a thumbs-up.

 

to continue:

The first thing I always build in electronics, if it requires it, is the power supply unit (PSU). For the console, it requires 24, 12, and 5 volts; each capable of handling 2 amperes.

It took me a long while to come up with a circuit diagram. I had to keep changing it due to available component specifications not meeting the requirements. I figured out a solution and went from there.

m9EztYm.jpg

 

For those who may be wondering why I go to great lengths recording the designs and drawings; others may have to know how to repair it.

All my notes etc will go into an operating and service manual for the museum.

 

Making the PSU.

B38bYkJ.jpg

 

Testing the PSU.

zaSyP8I.jpg

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