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Peter

1/72 Bridge Diorama

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I agree with Kevin: I also look forward to seeing your post notifications in my E-mail.  This is phenomenal work already. I can't wait to see more.

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Designed and built servo controllers for the gates. The gates rotate 90 deg. You can see on the oscilloscope the required change in duty-cycle to control the rotated position.

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Each servo has its own two trim-pots (blue squares) for adjusting the open and close position of the gates.

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Made wooden brackets to fix the servos and gate levers in place under the table.

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Each pair of gates has its limit switches, not for positioning the gates, but for triggering the console red and green gate lamps. Also to determine when all the gates are either open or closed. These brackets will fit over the servo-gate mechanism. The gate levers will enable the microswitch (on/off).

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Hi, Peter,

This project takes my breath away!  I've known for some time that a person must be an electronics engineer to build a model railroad layout.  Now you come along and show me that those same skills are required to operate a wood model bridge.  Obviously you are making your own custom circuit boards and know which chips and other components are necessary to solder into the holes.  Since this is all scratchbuilt, I know I would have an impossible number of failures in the trial-and-error process of getting everything to fit and function correctly.  I truly respect your abilities...and wish I possessed some of them.

I am looking forward to seeing the techniques you will apply to create the water and shoreline terrain to bring all this together.

Keep up the great work.  I am learning from you.

Ed

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I couldn't have said it better than Ed did. Brilliant work!

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Thank you @ewahl and @Mark Deliduka for visiting thread and kind words.

I suppose personal history of skills gained has lend itself to this first model. It sure seems to be a unique opportunity for me, though I did not see it that way at first. I am sure others also have transferable skills that could lend itself to a particular unforeseen task. A woman I know also found such an opportunity land on her lap, all her skills lend itself to comody theatre. Yes, I am grateful to have found a niche, after all this time. Or perhaps I should say 'the niche found me'. I feel the same way with sport, I tried all sorts of sport to no avail, until I had to do cycling for health reasons. Now I love it! Have been cycling for years. It is a sport that found me (I was not looking for it).

However, after saying all this, nearly all the steps I take on this model is done with a degree of apprehension. Some more apprehensive than others.

Modelling, as you know, has its challenges. I am certain we need them or else we won't get any satisfaction from building models.

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Both DC geared motors for bridge and boat require control circuits. Decided to use logic controlled circuitry for switching motor rotation (CW and CCW). Also discovered that the span would raise too quickly even with a 148:1 gearbox. Using a lower supply voltage, via a series of diodes, to the motors slowed it down.

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Also discovered that the motor shaft roation drifts when switched off. This drift needs to be accounted for when placing the triggers that switch the motors off.

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Building the two motor circuits on the one circuit board.

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Boat traverses up and down stream without turning around. It needs to be symmetrical, with two bow sections, so it does not look like to is reversing when the boat returns.

Bought two cheap wooden boat kits from China. Here is a photo edit to get an idea of what the boat ought to look like.

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I cut the two decks, cabins, and keels in half. Glued the bow sections together, with scrap wood supports. Planking was too stiff without heat shaping them first. Found a DIY method on the Internet. It worked real well. Here I am bending the gunwale first.

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Marked where I wanted the waterline to be. Then bent and added the waterline plank. All other planking was to fill the gap between gunwale and waterline.

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Then the bootom got cut off. Sanded the base flat on a sheet of sandpaper.

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Edited by Peter

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Wow, brilliant idea. My commendations on a brilliant fix.

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