Simond

Chaz I think you could tension the chains with a turn or two of fuse wire twisted like a champagne cork retainer. I guess you could somehow hide it, but I am conscious of your comment about the chains taking the paint off the corners of he load. Still hoping to get a chance to see DG.... Simon

Anthony Rest assured, it's not boring!!! It really, really, isn't! Kind regards Simon

I remain staggered by the sheer scope of the thing - it is truly magnificent! Simon

CC Couple of things - I found that I got exactly the same issue of the stepper grunting and wandering about a bit when it boots. Still don't know why. This was the impetus required to get me to go to Maplin and buy the photosensor! Pictures as follows Sensor buried in the ballast in the turntable well - I drilled 4 small holes and dropped the legs through. Ballast needs refinishing in parts, and I'll touch around the sensor with a bit of brown to tone it in a bit. I soldered the two bias resistors and the leads directly to the legs of the sensor. Red is +5V, black is ground, green is output. Ignore the orange, which is the feed to the turntable centre pivot from the polarity relay. As you can see, I araldited the wires to the board to stop the pins of the sensor breaking, or shorting. Glued white plastic sheet under the t/t and added a layer to reduce the clearance to a minimum - apparently, they differentiate better with a really small distance to the reflective item I played around with the threshold value of the sensor detection, and found that it was typically reading around 600 when open "to the sky", a bit higher as the t/t covered it, and then dropped to less than 50 when the white plastic card covered it. I set the program to detect something like 200 and this is the new "brain". Arduino pro mini, and Pololu stepper driver on a veroboard base. I've been wiring it up this week, and was hoping to have this all working first time but fortunately / unfortunately I discovered I had got the Arduino pinouts mirrored when I drew my schematic, so I'm back to the drawing board on this one - fortunately no damage done except to my ego! Best Simon

I'm brave enough to have a go at the bezels, but if you're making some buffer stocks... Well, you have made the tooling, it would be a shame not to get some use out of it... Just the 4 for now, if you wouldn't mind! Best Simon

Hi gcodori Please see my post 114 et seq in Jeff's thread - shows the stepper I bought, and discusses backlash http://www.rmweb.co.uk/community/index.php?/topic/76732-stepper-motor-turntable-drive/page-5 Hope this is helpful Best Simon

Hi all, The <> icon ain't there when I edit posts on my ipad, but it is on my laptop. Andy has modified permissions so we can attach .ino files to posts - this does make downloading easy, but remember to put the file in a folder with the same name. @ Pixie - stepper will surely work but might be overkill - a DC drive, perhaps by threaded rod, with limit switches, might be simpler to build and adjust, and may be cheaper too? EDIT. Perhaps a servo might work - not sure about accuracy & repeatability though. @ gcodori - steppers with gears are great, but as noted by Robin, backlash is an issue which needs to be addressed. There are two options as far as I am aware - always approach from the same direction, either by only going one way (not good on traversers...) or by overshooting and coming back, or alternatively, build a suitable constant into the software so it compensates. Effectively these are the same if the amount of overshoot is actually zero. See t/t program attached to the Arduino thread in my signature below for examples. Best Simon

Rod It was a very long time ago, 1986 or 1987 from memory, so indeed things may have changed, but I am pretty sure the subroutines I wrote had return values, and the Wikipedia article on subroutines supports this, suggesting I'm not senile yet! http://en.wikipedia.org/wiki/Subroutine I have heard the differentiation you have stated, but I'm not sure if this is general Best Simon

Anthony I'd be very surprised to see grass 3 feet high in the UK, rough scrub is unlikely to exceed 2 feet, and any open unkempt grass would be rabbit-cropped so a mixture of tussocks and flat bits. Best Simon

Dave Thanks for the post - few tricks in there, some of which I may well shamelessly copy. Robin I'm only just getting my head around the concept of functions. In the days when I programmed in compiled HP basic, and HPGL, they used to be called "subroutines", I think... I quite like the approach - more learning to do! Best Simon

Anthony I believe this is the stuff I used many years ago - it's a sort of thick paper with a "velvet" grass-coloured surface http://www.noch.com/en/produktkatalog/listview.php Best Simon

Robin I can't even find the link that got me to the YouTube page! I think it came from ModelRail forum, but can't find it Will keep looking Simon

Anthony, I model in "0" - like I said, good job it's "N"!!! Best Simon

Just found this rather nice implementation - I like the two-wire connection between lever frame (row of buttons...) and yard, and the consequently short wiring from servos to driver board Best Simon

Good job you're doing it in "N"... Best Simon

Thanks guys, I hadn't thought of flashing the led - absolutely obvious, once someone says it!!! I have a very good pal who know a bit about signalling - I'll ask him about it over a beer or two when I see him, but my understanding is that it is absolutely a table of "permits" and "prohibits" More when I can Simon

Robin, I was thinking of having two (groups of) variables attached to / incorporated in a function for each lever, one would represent the "released by" and the other would be "locked by", each referring to other lever(s) in the frame. This would allow almost prototypical locking schemes to be used. As it is unlikely to be feasible in any sensible way to actually lock the levers (small toggle switches in my imagination) I had in mind a suitably located red led to indicate whether any particular lever is locked. The other option would be to get a Modratec or Scale Signal Supply frame and do it properly, I think MSE also did frames, but afaik they didn't offer locking. In any case, it's overkill if we're already using an Arduino as a servo driver, (but the SSS ones are very nice...) I'll try to sketch something out over the next week or so - depends how things are at work - all day on the laptop doesn't leave one in the right frame of mind to start thinking logically! Best Simon

Robin Thanks for this! I didn't realise you could do an input pull-up on an analog pin Your programming appears to be rather more sophisticated/advanced than mine... I won't have a chance to try this out for a few weeks, but I'm interested particularly as your approach seems to offer opportunities for interlocking - thinking cap on! Best Simon

Hi all you will see that I have now moved all my program text out of the thread and added attachments. I hope to get a Pro Mini and programming interface for the turntable in the next few weeks, and will then install that permanently, I'll probably try to tidy up the code then, and post it. best SD

Thanks Robin I was on the same page, I had already been lazy and changed the name to ".txt", but it didn't let me do that either! Anyway, thanks to Andy, we can now attach ino files. Now, I need to work out how to go back and edit my previous posts to tidy the thread! Later SD

Right! Gordon - spoke to Andy, and we are now in Computer Control Dave - thanks for the suggestion - I don't think I have had a problem as it is, but your suggested code makes perfect sense - I'll implement at some point. Robin - Andy has enabled the attachment of ".ino" files. I am currently in a hotel in Poland with no access to my programs - would you like to try attaching and downloading a file to see if it works? If you're busy, I'll do it at the weekend. Whilst I have your attention, how do I edit a previous post (sorry if this is dumb...) to implement the quotation box per your suggestion? Thanks to all for the contributions Best SD

hi Robin thanks for that - next time... did try to simply attach the file but failed! SD

and another one... my turntable appears in JeffP's thread here http://www.rmweb.co.uk/community/index.php?/topic/76732-stepper-motor-turntable-drive/page-6 The program, needs a bit of refinement, and some comments, looks like this; I'll pretty it up when I have time, but it does work... best SD turntable_1mar14_a4988_subroutines_with_sensor.ino

Hi guys I have started an Arduino thread on RMWeb - please feel free to link, add, comment... best SD

I don't think I made my aims clear in my original post - please feel free to add your own sketches, and link to other threads - hopefully this will enable people find things that they are looking for! best SD