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May 02, 2020, 04:49 PM
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Hi Capricorn, thanks for your reply -

I've attached a picture that approximates the fields of fire. The HVwMS Aran was built around 1901 - I don't think it actually had any kind of directors - most likely manual sightings towards an approximate compass bearing that was shouted down from the conning tower .The ships I'm working on are 1/72 scale so lots of displacement, lots of space - could accommodate a lot of equipment without issue.

What you have done with the compass director is really quite remarkable - Ideally It would be nice to drive the turrets in that way and constrained by their field of fire....but that's 8 separate turrets - would an Arduino Mega be able to handle that driving that many?

Right now I'm just focusing on leaning how to upload software and run something simple like turn a fan on =)

Oh by the way, I do have these steppers on order to do some experimenting with...
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May 06, 2020, 09:18 AM
Big Boats Rule!
boater_dave's Avatar
One thing to consider is how many unique gun controls do you want? Multiple guns pointing in the same direction can be considered as one control. Maybe you can have the front main, left group, right group and rear main as four controls. The three guns of the right and left group maybe just have slighty different firing arcs, but all try to point in the same direction. And for the logic in the control, the same format would apply. From a relative bearing on the ship, which guns could point there? That logic becomes a line of code in the Arduino.

May 14, 2020, 06:40 PM
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NZ, sorry I hadn't been on for a while, I'm not very active here, it comes in bursts. I believe the Mega would run 8 separate motor circuits, a compass, plus a few more items. It has 54 digital pins and 16 analog, so 70 pins. You need 8x4=32 for the motors.

Not sure how big your ship will be, I wouldn't try too small. The Bismark at 1/200 is really too small just to run 4 turrets, although it can obviously be done. You are going to have a nest of wires that's hard to imagine. What Boater Dave suggests is a good idea, if you can cut down on the number it would be easier, on the other hand you'll have all the motors and most of the wires in any case, it just becomes a programming effort to add the separate fields of fire, the chip has the capacity no doubt. The director (pointer) can be just a dummy in the program, used to let all the turrets know which way they should point, if they are allowed.

The compass may take some effort, I really don't know that much about it, I was able to get one to work pretty well but it's not easy imo. A different module from what I used may better, and you may need to determine how to prevent interference from motors, drivers, propulsion motors, servos etc. It's an active place electrically and magnetically, so as a back up you may want to consider just a joystick control of the dummy director. I hope that you start a build log, either here or in the scale boats section, I'd be interested in seeing the progress. I'll try to remember to check back more often if you have any more questions. Good Luck, Cap
May 14, 2020, 07:00 PM
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Thread OP
Oh, I see now, 1/72 scale Aran. So it's about 48" long, 8" wide. Probably much deeper than the Bismark model so that will help a lot. Arduino does take a while to learn, some say other types are much easier, but once you do learn it it's really not that hard, and I think it has the most widespread use and available assistance (could be wrong).

I attached photo of the larger DD Fletcher I have, it has a mega. You can see all the wires, it had quite a bit of additional items besides the 5 turrets and one director. I managed to use almost all the 70 pins

And yes, those are the right motors to use imo. When you eventually get to the point of running the turrets you may want to mount them with a friction pin of some sort so you can pull them off, re-aim them manually and so they'll slip when the motor does not behave as planned and turns the guns into the deckhouses.
May 27, 2020, 05:50 AM

3 turrets turning , 9 guns elevating - controlled from any WiFi enabled device(tablet / phone etc - video shows iPad (screen top right) being used as controller) - operating range approx 1 mile more to come....

HMS Rodney - 3 Turrets Turning, 9 guns elevating... (1 min 36 sec)
Last edited by G6SWJ; May 27, 2020 at 07:11 AM.
Jun 09, 2020, 12:01 PM
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Thread OP
Pretty neat Gw. I like the independent elevation on the guns. Joe
May 14, 2021, 09:42 PM
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I found this thread a few weeks back. It made me pull the trigger on a Deans Marine Narvick and now I'm teaching myself Arduino to do better than the Hack Job I did to the 1/72 Fletcher I bought (latest version of the old Auquacraft one outta Motion RC but we all gotta start somewhere for turret rotation)
So for all of the Giants whose shoulders I'm crawling up on that have posted here thank you for all the knowledge you have left for those of us next up to the plate.
May 18, 2021, 08:48 PM
Registered User
Just found your thread and it is very very interesting
Been playing with Arduino during prolonged home recovery from a winter injury.

A few resources to share of what I have learned:

Adafruit has a stackable motor driver board that has capacity by stacking boards to directly run up to 64 steppers
The advantage here is you don’t need separate driver boards for each motor and you also can mix with extra servos or d/c motors. It is Arduino compatible with full library

Pololu also has a great series of robotics products for interfacing RC to Arduino.
You can buy RC digital switches that you can directly input to your computer board without using much code.
Their forums offer lots of help on their products.

I have found that YouTube has a series of great tutorials applicable to your goal.
Some of the newer Arduino clones that use the Arduino library are much faster for RC use.

The use of interrupts is the fastest way for the boards to respond to input from multiple receiver pulses from RC receiver.

Arduino is a very slow microprocessor. 16 MHz.

The AST32 boards (Blue Pill) run at a much faster speed than the Arduino and are better for your project and very reasonably priced. It runs on the Arduino compatible library.
It’s speed is 120 MHz!

Joop Brokking has a series of tutorials on YouTube that are very helpful learning how to read rc signals all the way to making a drone.
Here is a link to get started.
Getting started with the STM32 microcontroller - STM32F103C8T6 via Arduino (12 min 53 sec)

There is also a full function stepper controller board that allows input of limit switches that I am playing with to make an automated boat launch winch on the Robbe Berlin for the daughter boat.
Here is the You tube for this reasonably priced full function board from Marlin P Jones & Associates and FleaBay.
May 21, 2021, 07:18 PM
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Thread OP
Well thanks both of you for logging in. I don't look often so I just see the input now. The holy grail of "perfect" turret operation is still there to be snatched. Bruce Murray has honors at this point with his latest Bismark video. A more vibrant prossessor as jshander suggests could be a really wise change. And there is no reason not to use premade modules for the steppers that stack on top. Anyway you want to go about it is fair game. I'd just like to see the thing in a finished form, a fully functioning turret operation system that has no detectable flaws and that is yet to be seen by me. Bruce's system is quite functional but flawed, as is mine, the behavior of the thing is lacking something. sprucaman, you have no reason to doubt your own place in this effort, if you want to do it I am sure that you can.
Jun 03, 2021, 06:21 PM
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Thanks for the encouragement Capricorn I figured the thread was basically dead and didn't expect reply's except for those like me who passed through and found the idea intriguing enough to have a go at it.
I'm still learning the coding so I can actually write the sequence while understanding what I'm writing and have to admit to not being efficient about how I'm going at it. But I do have a bit of background in logic circuits (and piping which can be more similar than you'd believe) and remember a bit of DOS from high school...yeah thats been a few decades. And as such I've already got a decent outline of steps and I'm just learning what words I need to tell it what I want it to do and how. Once I get that done then it'll just be a matter of plugging in the correct variables.

Bruce's system is pretty good and so is yours. Next bits are my thoughts on how I plan to approach this on top of what I've seen here and other places. With much based off what Bruce seems to have done.

The only way I see for the Bruce program (not having seen his code though I have to admit I'd love to steal both your and his code) to remove the lag between each of the turret sets is a 3 Arduino setup unless you know a way to make code run in parallel. There are smaller Arduino's avail but still researching there and need to get the code thing down before I get that fancy. And downside is more wire and the potential of Captain Kirk sitting on top of my boat screaming I NEED MORE POWER SCOTTY
-#1(the command Arduino) takes inputs (compass and controller) and uses them to create a desired output signal (turrets point thataway) maybe put the director on it too. (means director will likely always be just a touch ahead of the guns but I think that'd be pretty realistic)
-#2and3 would be for each of the gun sets taking an output signal from #1 and using that to direct the turrets. The initial homing could still be run from each Arduino board for its respective set and if power for all three is on the same switch all would theoretically (yeah probably not best bet would be turn on #1 then #2&3)home and be ready to go.
Reason that may work is the Arduino has to do each step in sequence so if you broke the code out into the sections and had each running only what it needed each could be running at more or less the same time. (The director lag may even be removable by sending the signal out before turning the stepper once again need to get better with the code)
it sorta becomes (breakdown is how the steps play out in my mind A-inputs/poweron B-director C&D-turrets 1-homing
.......... C1 - C
A-B1< - B<
...........D1 - C

Next is the Jitter
Maybe its from the compass module. As the boats on the water its moving in multiple axis. maybe find a way to put a time delay or spread (range? plus minus? not sure which tearm really fits here) that lets its input jump-around a bit and then averages the inputs for the say last 2 sec then uses that number to determine it's value. Downside to that is things may lag slightly behind on a hard turn but if you play with the values maybe that can be overcome.

Lastly Homing
.... I'm actually considering dropping the steppers for the turrets... On my Fletcher the servo's are capable of turning well over 180. In fact I think I can coax nearly 400 degrees if I swing one hard stop to hard stop... (did this by hand gently not signal and servo still works and I don't need NEARLY that much) There is code that lets the servo ID its zero and I've found code for controlling servo's No reason the director cant be a stepper and the turrets servo's especially if i end up a 3 board rout. If I can get my head wrapped around a new language I may be able to rather easily retrofit my Fletcher.With a move for work this fall bouncing off me I'll either have a working system by end of summer or it'll be a year. Either way I'll at least drop some picks once I do.

edited for a bit of readability and once again thanks Capricorn
Last edited by Sprucanman; Jun 03, 2021 at 06:32 PM.
Jun 03, 2021, 11:20 PM
Registered User

New hope in easier turret control

To those striving for a different approach than steppers.

I just learned about next generation Hitec digitally programmable servos

Like all new hobby stuff, it probably will take a while to come down in price.

The newest is the HSR-M series of digital servos

These servos donít use a carbon potentiometer for position feedback.
Optical encoders are utilized to provide precise feedback up to a programmable 7 turns or continuous rotation.

Speed of these servos can be slowed down
Slow ramp up speeds also selectable on program.

Unlike the previous generation multi turn sail winch servos that lack precise end point return, these have precise endpoints that are optically encoded for complete precise feedback at whatever the end point is programmed.
Banks of Turrets can be coupled together with a belt drive

Microprocessors such as Arduino, Blue chip donít retain precise feedback from servo position on start up from Flash memory.
they provide programmable pulse width control without any position feedback,
Jun 17, 2021, 08:50 AM
Registered User
Thread OP
thanks again, and sorry for not keeping up, I just check once in a while. Sprucanaman, good to hear you are giving it a go. I'm not sure I follow all of your points, but yes there is room for improvement. I think the lag on Bruces turrets could be improved, there's always a bit of lag but it seems noticable. I think the jitters in mine were an interference issue, never could get rid of it and much worse with the propulsion motors on.

And jshander too, if there are servos that work well that would be much easier, it sure makes sense that servos could do it, I guess I never invested in high quality ones that could do it. encoders would be great, all in one package and you can toss the steppers. I'm afraid I've had my fun and am not really active on the turret stuff at this time. Please do post videos and pointers though, I'd like to see more ships with this feature but it's a bear of a task to make it really function smoothly. Cap

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