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 My home made Rail/Dolly - ongoing project... 
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Joined: Thu Jul 24, 2014 4:52 am
Posts: 83
Post Re: My home made Rail/Dolly - ongoing project...
Another progress report!

Here's what I had to do to the centre support to get the new bearing brackets in place. At some point I will redesign them a bit to remove this obstacle.

Image

It doesn't really affect how well the tube is held so it's fine.

The new bearing clamps seem to do the job ok. They're not perfect but give it a lot more clamp strength:
Image

And I've fitted the bolts to the 4 corners to give it small adjustable feet:
Image

A bit primitive but they'll do for now to allow it to sit level on a slightly uneven surface. Will just keep a short 10mm spanner with me for doing that. Obviously it'd be no use on sand or other soft surfaces but I'll make some little disc feet to go beneath until I get a better solution made.

I've tested the winching qualities now that it has the extra bearings, and it's able to lift my 5D mk3 up to about 45 degrees or so before it's either getting the stepper slipping or the belt.
I think the belt has enough tension so I suspect it's because I'm using microstepping at the lowest level, as I've found in the past I was able to stop the stepper moving on different settings.

I need to look a bit closer and if need be, adjust the stepping and the code for the step delays. Don't think it's the belt but I could be wrong.
Even so, this is a massive improvement over previous ones which would only move at a very slight angle above horizontal.

As you can see as well, there's a horrible bend to the carriage plate, hence needing washers above one of the bearing carriers.

Also, the belt runs quite high off the ground, which is great to avoid tangles in bits of grass etc, but I think what I might do is buy some thin wall plastic channel which will cost/weigh just about nothing, but can sit beneath the centre where the belt is, and prevent anything interfering with the belt if I set it down in the grass or whatever.


Tue Aug 26, 2014 1:19 am
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Post Re: My home made Rail/Dolly - ongoing project...
Mate, that is looking really really good!
Man a 3D printer helps out immensely.

How much flex is in the bearing carriers?
I get flex in mine, but that is due to everything being made out of HDPE as it is too soft.
I'll scrounge up something harder and remake mine.

What stepper driver are you using?
You might not have the amps set right so are under powering the stepper.

As far as working out if it the belt slipping, just stop the stepper while it is powered, that is when it has its strongest holding power and see if you can push the carriage along.
You might need that belt tensioner after all.

cheers
Andrew


Tue Aug 26, 2014 3:22 am
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Post Re: My home made Rail/Dolly - ongoing project...
Must admit the printer really is a plus. It was a nightmare initially though as I got it partly built from a friend and there were a number of flaws I had to spend a long time sorting out, plus getting the firmware right was a pain too.

Got the tripod attachment nicked from the last rail and fitted it, so I at least have a tripod at one end now. I've tested it so far up to 58 degrees then it slips, but I'm pretty sure now it's the stepper not the belt.
So I need to meddle with the microstepping and step delays. Not tried your suggestion yet as the code I've currently got it running doesn't have a stop point - once it's switched on it's moving. Like I say, it's basic! :D
I'm sure I set the vref for the driver current output correctly but I'll double check.

The driver by the way is a Pololu.

The plastic is pretty damn solid to be honest. The pink stuff is PLA which is easy to get good prints with, and it's pretty hard. White bits I've printed are ABS, which is way less convenient to use (much higher bed and extruder temperatures and hard to get to stay stuck fully while printing sometimes), but I think is a better plastic. It is slightly softer but still gives strong and solid prints. The brackets shouldn't really flex by any noticeable amount.


Tue Aug 26, 2014 4:16 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Im seriously considering a printer now, what one have you got?
That's right I forgot that you were using Pololu drivers as well.
Ive killed about a dozen of them so far, lol, but just got another 6 delivered.

My 3 Pololu driver board is working a treat, milled on the CNC.
I need to make another one now, might actually make a few minor changes to allow for easier connections.

Im also moving the Pi and drives to the side of the dolly, hanging off one side and the batteries on the other, or maybe pi on one side, Pololus on the other and batteries on each side to even up the weight.

Have to see how I go :-)


Tue Aug 26, 2014 4:25 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Printer is a reprap prusa (i2 I think), and it really is handy.

You can buy them ready made on ebay or whatever, or buy cheap bits like threaded bar, and source the other hardware bits like steppers etc, then buy a kit of the printed plastic parts.
The plastic is cheap too, I pay about £12 delivered for 1kg spool of 3mm filament, delivered.

Probably a bit bad on the electricity bill if used a lot though. The end brackets for instance on my rail take 3 hours each and there are 6 in total, and it runs a 17a PSU, sooooo.....

Can't speak for other variations of printer but there's a lot of different ones out there. If you google for reprap forum there's tons of info on there so a good place to do research if you're thinking about it, or the reprap wiki pages.
Helpful community too.

Don't get me wrong, a 3d printer like this is not simply a plug & play thing that you can rely on 100% to always work flawlessly, they require a bit of tech savvy, and require tinkering with now & then, but I think you're quite safe on those grounds!! :)

Well my CNC machine's Z axis arrived just now, so hopefully I can get on with that and soon begin 'making chips' as they say! :D

And also, the touchscreen for the raspberry pi arrived too. I just don't have the Pi itself yet!


Wed Aug 27, 2014 4:17 am
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Post Re: My home made Rail/Dolly - ongoing project...
Cool, thanks for that info, it is great.
I had looked at that printer.
The servers that I have humming away in my garage 24/7 are probably drawing more that that, so I probably wouldnt notice the power increase :-)

Im looking forward to seeing the CNC Mill coming to life :)

cheers
Andrew


Wed Aug 27, 2014 11:45 am
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Post Re: My home made Rail/Dolly - ongoing project...
Yeah I guess it shouldn't matter in that case!

I've got my z axis mounted on the mill now, just need to:
Mount the stepper for it (making a bracket with the printer)
Wire everything together in a box
Figure out the software

Not yet been able to test the new rail yet. :(
New memory card has come too, a 32gb sandisk SD extreme (60mb/s write) which should allow frame rates comfortably of 1fps+


Wed Aug 27, 2014 11:41 pm
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Post Re: My home made Rail/Dolly - ongoing project...
good stuff!
looking forward to seeing it all together :-)ˆ

I'm about to go cut out the latest revision of the stepper driver PCB, then decide which stepper I am going to use in the Pan and Tilt Axis.

Image

From left to right are;
Nema17, Nema14, Nema11 and Nema8


Thu Aug 28, 2014 12:25 am
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Post Re: My home made Rail/Dolly - ongoing project...
I was looking for a bracket that I can use for the stepper motor mount that will allow me a quick adjustment, and found this.

http://www.thingiverse.com/thing:119814

That was what you were after for the cable chain on your dolly, I thought that the file to print it would be ideal :D


Thu Aug 28, 2014 5:54 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Thanks - a friend has made similar stuff on his printer so it might be the same item.

Well I finally got out for a test. Not an amazing piece of footage but it's fairly smooth. The speed does increase part way through though.
I could hear people approaching with dogs and didn't want them in the clip so I increased the speed, but I should have left it alone really:



It's working well but there is flex end to end to an extent, and while the rail seems solid the camera can still wobble when very windy, so I need to investigate.

Raspberry pi has arrived and I've got it up & running with the little touchscreen. It's cool but until I get other things ironed out with the rail I'll keep the arduino in use and meddle separately with this.


Sun Aug 31, 2014 12:25 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Oh, and I have all 3 axes working now on my CNC conversion, except now I've assembled all the electronics & wiring together in an old PC case I've got a strange gremlin with it.
Sometimes the 3 steppers work perfectly in both directions, but then suddenly they will begin only moving one way, regardless of which direction button you press. It's not the mach3 software as that registers the correct +/- values.

I've read this can be cable problems (checked and can't find any issues) or interference potentially. I think it may be the latter but have no suitable shielded cable other than cat 5, which is not suitable for this.


Sun Aug 31, 2014 12:29 pm
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Post Re: My home made Rail/Dolly - ongoing project...
that time-lapse looks very smooth, great result!

I havent experienced your stepper issue on the CNC, but I thought that I had the same issues with noise.
I cant find any 4 core shielded cable either so I gave up looking and my issue went away.

Andrew


Sun Aug 31, 2014 12:39 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Sorry for the lack of updates guys! Been busy.

Thanks Andrew

As a rule I'm pleased with the new rail in practise but the carriage is not ideal as it still has a high centre of gravity and I'm not too pleased about that being the case still.
Will have to give some thought about a potential redesign to get round that. The carriage is fairly wide so I think there's scope to potentially lower the platform down and have inverted bearing blocks perhaps. We'll see but no real rush to do it.

Here's a sequence that would have worked out nice if I had the rail with me (family bbq on beach so was already carrying a lot!) and my wits with me. It came out really underexposed somehow and have had to spoil the image quality with the amount of fill in light to get it working. Doubt it's any use but I might go back with the rail and do it again. I'm curious about how long exposed shots of the sea would come together as a timelapse. Could be interesting!



Here's one I did at a tiny village near me. The place is called Cregneash and is like a living museum. The houses have thatched roofs, and the straw for this can't be used like normal baled stuff from a combine harvester, so it's gathered by hand and put in the piles you see here, 'stooks'. I love to see them rather than bales and I was quite pleased with how this clip looks:




Here's another, longer one from the top of the same field as the sun went down. Would have been nice to be zoomed in more to make the sun bigger, but I wanted the gate in the scene.


Back to the dolly again, I've finally had success getting something up & running with the Raspberry Pi and touchscreen, for a potential upgraded version of the dolly controller over the arduino.

At first I when I got them, I could not get the screen to display anything other than white light, and thought I must have cocked up the soldering somehow, maybe causing a short. Was just the linux installation though and I got it working.
Next I had some issues with the desktop display of Raspian, but needn't have worried as it's not using the desktop anyway. Got it sorted with a reinstall though.

So finally I got the lapsepitouch software installed on it, and have it working with the touchscreen! It's really nice and the chap who's written it has done a grand job but I want to modify the code once I understand it.

Image

Long way off being able to use it on the dolly but cool to have it working.


In other news, my CNC machine is fully functional now. I just need to spend time getting my head round all the software required, then spend ages making sure it's set up correctly before I try cutting chips with it.
I've got it to do some handwriting, but not dared anything 'proper' with it yet as I have to set up fixtures and limit switches etc.

Also need to figure out what CAM software to use, ideally free, although may not be necessary as I found a sketchup plugin called sketchucam which is meant to output gcode from sketchup.
Exciting to have it almost in use. I can't wait to try making stuff like the hardware for pan & tilt stuff etc. :D


Wed Sep 10, 2014 11:48 am
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Post Re: My home made Rail/Dolly - ongoing project...
I was wondering where you were up to 8-)
Unfortunately Im in the middle of selling my house, so all my stuff is packed away and I have no chance of getting to it for a few weeks at least.
I got the prototype dolly running however and that is working well, we are just ironing out a few bugs.

Ive started collecting the hardware for the pan and tilt axis and had to get the worms and worm gears for the UK in the end. Ended up being about $60 per set, but they are fantastic kit.

Your time-lapses are really really good.
The sea one is fine, not too dark.
Longer exposures are tempting but I think that waves do something strange when you time-lapse long exposures.

The other sequences are absolute crackers!

Do you shoot in RAW?

That is great news about the CNC and the alternate dolly controller, that controller looks very good!

OK CNC software.
Inkscape is free and works very well for 2D profiles.
Makercam.com is free and works very well for turning the Inkscape SVG files into 2.5D profiles for cutting.

I've not found (nor have I tried) any 3D CAM software yet.


Wed Sep 10, 2014 12:04 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Thanks for the input again.

Yes I shoot raw, always really. I hate the thought of not being able to correct something that might have been really good but slightly out in terms of exposure or white balance etc.
That said, the sea one I'm really not happy with as the image quality is rather poor. I doubt I'd use it anyway since I hadn't used the dolly for taking that.

Do you happen to have a link for the place you ordered the worm bits from in the UK? Hope you keep us updated with progress pics as yours comes along.

I'm going to start looking at the code for Lapsepi imminently anyway since I have it working.
Also need to make a little circuit for the shutter release of course too.

I'll have a look at those programs you've mentioned, thanks!


Thu Sep 11, 2014 9:01 am
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Post Re: My home made Rail/Dolly - ongoing project...
Good, you HAVE to always shoot RAW, the quality difference is chalk and cheese :)
I got the gearing from http://www.hpcgears.com/ they were excellent.

I've just accepted an offer on my house yesterday, so I can get untidy again next week, meaning that I will be building my system again.

I can't remember if I posted it or not, but here is the new stepper carrier board.
Image

There you can see all the new parts, sorry about the crappy pic.
Nema8 and Nema11 steppers.
The right angle brackets for the pan and tilt axis'
The new stepper board next to the Raspberry Pi.

The new board has the 3 Pololou drivers, a 40 pin connector to the Pi, the 3 stepper motor connections, 3 limit switch connections, a power button connection and the high power input for the steppers.
Everything link from the Raspberry Pi GPIO is via the single 40 pin ribbon cable.

Now that your CNC is running you need to get yourself some 'V' bits and then cut out your circuit boards ;)


Thu Sep 11, 2014 1:44 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Those stepper boards of yours are great!

I was wondering earlier actually what changes I'll need to make to the lapsepi code to use steppers instead of DC motors. Do you use wiringpi for controlling those pololus?
I haven't actually looked up how to use a stepper and pololu with a pi yet but I presume it's very similar to with an arduino. The wiringpi addition I think makes the pi behave somewhat like an arduino in respect of input & output pins and the way they work, although I'm not savvy with what's so different about the pi to begin with in this respect.
I know little about the arduino and even less about the pi I'm afraid, but I need to have mine probably a little similar to yours in the sense of 3 steppers running from the pi, via pololus. The main difference I guess is the touchscreen interface that I'm using from lapsepitouch.

I need to order some pololus too, as I think at present the only spare I have is a stepstick one. Should do to begin with though to give the transition from arduino to pi control.

Hopefully I'll be able to cut circuits eventually yes. Might be a while yet.
I've just rewired the power cables into the CNC control box tonight (an old PC case), and fitted them to proper switches etc. I need to get my head round the proper setup of fixtures and so on in Mach3 though before I try cutting anything.


Thu Sep 11, 2014 2:16 pm
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Post Re: My home made Rail/Dolly - ongoing project...
So, for the Pi, yes, we are using wiringPi.
All the code is in Python and there are various scripts that do different functions.
i.e. one that is the setup that defines the I/O pins,
one that outputs the Step and Dir pulses to the Pololou's for a given number of steps and direction, and also ensures that we ramp the speed up then down on every move so reduce the shake
one that controls driving around manually by inputting a MM distance on the dolly, i.e. move the dolly to 1,352mm
that same script also does the Pan and Tilt in Mils (17.7 Mils to a degree)
it also lets you save that position as either the start or the end,
one that communicates with the camera via USB, determines what type of camera it is and what functions are available to control
this one lets you set aperture, shutter speed, ISO from our interface and tell it where you want the images saved (on the camera SD card, or the Raspberry Pi storage)
one that kicks it all off and run your time-lapse controlling the dolly, pan and tilt and camera.

etc etc, there are loads of them :lol:


Thu Sep 11, 2014 2:51 pm
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Post Re: My home made Rail/Dolly - ongoing project...
That sounds very clever and very complex!!

Well I've not progressed any further yet - just so many things to be done - too many projects.

The aurora was meant to be visible last friday so I took the rail out with me after doing photos of the Manx Rally, but it clouded over sadly.

I notice one end bracket needs redesigning for more strength. It hasn't broken but the belt tension is bending it (hasn't actually separated any layers of print visibly but it must be doing that at a tiny level).
It's good to identify these issues though of course.

I still haven't got round to looking at what will need changing for the lapsepi code to suit my needs.

I need to cross reference code other people have done for pi using pololus with the lapsepi code, and try to swap out the relevent bits I guess. Am normally too tired to concentrate on stuff like that in the evenings though, and too busy at the weekends.


Tue Sep 16, 2014 5:31 am
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Post Re: My home made Rail/Dolly - ongoing project...
I feel your pain.
between selling our house, looking for a new house, packing everything up to be neat, work, and my Scouts commitments and family, there is no time left in the day for projects at the moment.

We've identified a big weakness in my tripod mount, so I've redesigned it to have an incorporated quick release plate profile right on the brisket, reducing one more thing to be attached.
That should be heaps stronger.

I might have some progress after this weekend.

cheers
Andrew


Tue Sep 16, 2014 1:07 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Hope things are going to plan Andrew - house moves are never fun!

Well I haven't really progressed at all lately in terms of getting out catching footage, and my rail is damaged currently too, but I have finally got round to compiling a rough edit of a bunch of my clips.
It's not in any real order and some of the footage needs tweaking where it's bumpy/jerky etc, but it was a good chance to try out some editing.



Sun Sep 28, 2014 2:33 pm
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Post Re: My home made Rail/Dolly - ongoing project...
I'm starting to get back into the dolly build. We are refining the software to a fantastic level now, very happy with it.
I've just been on a 3 day hike as well, so I'm buggered, and still looking at houses, so a little distracted.

Your video is good, I like it. There are some fantastic scenes in there.
Your website address at the end prompted me to have a sticky, and wow your photography is stunning mate, very very impressed! :o


Sun Sep 28, 2014 5:56 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Thanks Andrew, very kind!

Your program sounds great, are you going tip be selling it?
I think that's going to bee the stalling point for my project unfortunately.

I've missed it, but what are you using to control all the input parameters when it runs?


Mon Sep 29, 2014 7:01 am
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Post Re: My home made Rail/Dolly - ongoing project...
Hey mate,

yeah we will be selling the whole dolly setup, hopefully. :D
I'd be happy to bring you in as a beta tester if you are interested.

So we have the raspberry pi, headless, with a wifi dongle.
The Pi sets up a wifi hotspot and you connect to it with any device.
Smartphone, tablet, whatever you have.

All the setup and control is done from that device.
We have a calculation routine in there that lets you setup how many steps per mm the cart moves, and that allows for you to say that you want the dolly to go from 100mm to 750mm position.
You can direct drive it, so say, go to 500mm then when it gets there set it as the start or end point.
When you have the start and end points set, you save the routine and can make as may more as you want, then you can say, 'run all routines'.
That way you can get quite complex movement, especially when combined with Pan and Tilt

I know that I keep saying it, but Im getting real close with the hardware now, im jut keeping refining the dolly cart now so that it is easy to manufacture and reproduce with the minimum of manual steps.
All the designs to date have required some manual tweaking to get them to fit the rails properly, and that isnt practical as it means manually making a part, and if it doesnt fit, remaking it.
Im not doing that if we are selling them :evil:

cheers
Andrew


Mon Sep 29, 2014 11:48 am
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Post Re: My home made Rail/Dolly - ongoing project...
Heh heh - I know the feeling Andrew! Earlier on in my build I was wondering about the prospect of selling self assembly kits for people in the UK once I have mine satisfactory and tested for a period of time, but if I did, it would just be with basic controls and not all the clever interface that you're doing.
I'm not sure I would end up doing anyway since the printed plastic parts have a potentially doubtful longevity when used for certain parts. I would hate to sell things then find later on down the line that they didn't last and have upset customers, or worse still, camera kit being damaged as a result of a failure. I'd feel terrible.
Mine is nowhere near that sort of level though, and in all honesty I doubt I'll end up doing that as it seems like a lot of hassle. I don't know - it'd be nice to, but I can't envisage it at the moment.

It's a pain reinventing what you've already done yes, I've had to a few times with various bits. The current problem being the pulley bracket at the opposite end to the drive stepper. In hindsight I did a rubbish design for the bracket, and gave no thought to its strength when under tension of the belt.
It broke anyway, so I've redesigned a couple of times since and just got it rebuilt tonight with a new piece that is way more robust.
I also need to tweak the bearing clamps as some space has somehow appeared and the cart now wobbles where it didn't used to. I think some things have obviously moved so I need to correct it. At some point when time permits I need to better the current design anyway so it inherently grips the rails more positively than it does now.
This design was a little hasty out of impatience to get something up and running (what I always do), but I don't mind as it helps me recognise the flaws and eliminate them.

The other issue I have right now is that I'm itching to try some night time stuff but had the dew problem with my lens the one time I tried. I've just received a little PWM controller I bought on ebay, so I'm going to be making a little lens warmer that is powered from the main battery pack. I was going to make a belt of resistors to provide the heat (since I have a load of them), but I think a better option would be to use some nichrome wire. Would have to work out a load of maths either way!

I forgot what you'd said before about controlling yours sorry - my bad! My mind is increasingly like a sponge for what people tell me. It just soaks up info, but then it seems someone comes and squeezes it quite regularly!!!
That's a great setup though. I'd love to try beta testing it if it would be useful for you. Be warned though I'm pretty good at breaking software others write at work! :D
I've just ordered some dc-dc converters so I can run my Pi from the 12v battery pack I currently use.


Mon Sep 29, 2014 12:47 pm
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Post Re: My home made Rail/Dolly - ongoing project...
I'm exactly the same, bang out a design to get something built, then go, oh shit, that doesnt work, or that isnt as good as it could be.
Pretty much constant refinement, but that is good I guess.

Yes a dew heater is a must!
We are building one into the dolly controller. I've specified the design and worked out exactly how it will work, but Col hasnt started on the code yet, there's been bigger fish to fry.
If battery life isnt an issue, you can just power the dew heater all the time, that is what I do currently.
All it needs to do is to keep the keep the lens above ambient, but a tiny bit.
I've planned a temp sensor in the heater, and one on the Pi, as well as a humidity sensor, so that we can calculate the dew point properly then only use the heater when there is a risk of dew, but it might be overkill and we might just go for a PWM
control to keep the lens above ambient temp.

I have read so much stuff about dollies that I have no idea where most of it came from ;-)

Breaking software is a good knack, and important as a beta tester ;-)

cheers
Andrew


Mon Sep 29, 2014 1:03 pm
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Post Re: My home made Rail/Dolly - ongoing project...
That's quite fascinating really mate - what sort of night time temperatures do you typically get where you are then? I think I sort of assumed it wouldn't be a worry for you and that it would still be relatively warm in the night time.
I don't mind having to do it though as it's kind of cool to be making little extra features like this.
I'm going to read a few diy articles on making one then see if I have sufficient resistors of the right sort of value to make something. Doesn't need to be anything awe inspiring really.

If you don't mind me trying your system out then feel free to drop me a message to let me know what I'd need to do, and if you want certain aspects of it testing in particular etc, then I'll do what I can to assist.


Mon Sep 29, 2014 1:12 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Yes, we do get quite strong dew's in Australia, especially in the cold times of the year.
Seeing as I do mainly night shots, I want low levels of light pollution, and that means getting out away from Sydney.
The closest place for me to do that is the Blue Mountains and they are considerably higher than Sydney.
ie Sydney is on the coast so basically 0m, whereas the mountains are mostly at around 1,000m

It doesnt often happen, but when the dew point is reached the lens fogs up right away.

I bought a Dew Not strap from the USA and it is great.
It was about $20 or so and I just power it all the time from a LiPo battey.

There are a new type though that is powered from a 9v battery that clips directly to the strap, and does it all itself.
This dew heater malarkey is fro the world of astronomy, so have a look at some astro how to's for the instructions there are quite a few.
Also, there are quite a few good forums around and one that I am on iceinspace.com.au has a few people that build dew straps and heaters out of the love of helping people and sell them basically for cost.

cheers
Andrew


Mon Sep 29, 2014 1:36 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Thanks Andrew - yes I'd noticed most sites I'd found for these devices were telescope related rather than photography per se.
iceinspace was one that I'd looked at too.

Does a 9v battery last any useful amount of time for a heater? Handy if it does but I have visions of those things lasting about 5 minutes for any device that needs a little bit of current for some reason.

I'm lucky here in that generally if I wait until after 1am then I could have perfect dark sky even in my town as the streetlights go out at 1am and you can see the sky so bright then. A few local towns keep them on all night so you have to be careful still which direction to point your lens.


Mon Sep 29, 2014 1:50 pm
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Post Re: My home made Rail/Dolly - ongoing project...
Apparently the 9v battery ones can last a month or something ridiculous, it sounds too good to be true.
Streetlights going out at 1am is absolutely unbelievable. that is fantastic!!


Mon Sep 29, 2014 1:58 pm
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Joined: Wed Nov 11, 2009 10:45 am
Posts: 1685
Location: Merritt Island, Florida, Estates Unitas
Post Re: My home made Rail/Dolly - ongoing project...
The 9v dew heater sounds sweet! I've been using chemical handwarmers taped to the lens.

Here is a link to some handwarmers.

http://www.ebay.com/itm/NEW-40-Grabber- ... 2ec4899ecd

I didn't use the old dew heaters because they had a power box and needed a 12 volt battery which took up more space than I liked

but I'd like to try the 9v ones.

Do you have the name of the 9v heaters or better still, a link to them?


Tue Sep 30, 2014 4:34 am
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Joined: Thu Jul 24, 2014 4:52 am
Posts: 83
Post Re: My home made Rail/Dolly - ongoing project...
Must admit those 9v ones sound great if they last a long time.
Just makes me slightly skeptical as heat needs a lot of power and 9v batteries generally don't hold up well with any sort of high drain use.

Interested though for sure...


Tue Sep 30, 2014 4:49 am
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Joined: Thu May 15, 2014 5:28 pm
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Post Re: My home made Rail/Dolly - ongoing project...
I've used the chemical hand warmers before, I have a whole box of them ;) but they weigh the lens down and if you're not careful they will twist your focus ring.
Here is the link to the 9v ones.
http://www.tech2000astronomy.com/zap/

I have not used them, but they were suggested by others in an astronomy forum as something that might work.

They say 10 nights of telescope work on one 9v battery

I use a Dew-Not
http://www.dew-not.com/index.htm


Tue Sep 30, 2014 11:56 am
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Joined: Thu Jul 24, 2014 4:52 am
Posts: 83
Post Re: My home made Rail/Dolly - ongoing project...
While since I updated here sorry! I acquired a non working jetski so it's distracted me a little having to strip down its engine and order bits etc. Too many projects!!

I've got a lens warmer made now, using about 16 1watt 330ohm resistors in parallel and a cheap PWM controller.
Not tried it in the field but it certainly warms up!!
Image

I've also nearly made the pan axis hardware now for my rail.
Basically I need to fasten it to the carriage and add a screw thread for the tripod head to attach, then the hardware is done.

Image

Image

Image

Image

I've been writing a new program for the arduino that will control it, and I've also made a cable/circuit for shutter control, which works nicely.

The program is being worked on so that it can control both axis, plus set the shutter time and interval, and of course will be changed now to only move between shots, so that it's suitable to use at night.
Having a bit of teething trouble with the arduino code getting a loop of code to behave correctly but I'll get it sorted soon I'm sure.

It's also using a 16x2 LCD display to show the values it's set to. I need to do a little more electronics etc for the pan axis and so on.

Last thing is that because I now need to run wires from the end of the rail to the carriage I've bought some drag chain for the wires to all go inside, to try and keep it neat, although neat is against my very being so we'll see how that pans out......

Finally, I hve a new photographical assistant - very excited although he's not been launched yet. I don't yet have the associated camera hardware either:
Image


Sat Oct 18, 2014 7:05 am
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Joined: Thu May 15, 2014 5:28 pm
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Post Re: My home made Rail/Dolly - ongoing project...
wow that all looks great.
Nice work on the pan axis, that looks super solid.

Im in the process of getting to move in a couple of weeks so Im not focussed on building at the moment, but my pan and tilt axis is nearly finished as well.
They are two separate modules that connect together, or can be used separately.

Ill post a few photos in a couple of days when I have assembled them.

I would love a quadra copter, that would be fantastic :-)

cheers
Andrew


Sat Oct 18, 2014 12:55 pm
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Joined: Thu Jul 24, 2014 4:52 am
Posts: 83
Post Re: My home made Rail/Dolly - ongoing project...
Thanks Andrew

I've built a new circuit to combine everything more or less, and written the new code to control it but currently having some difficulty getting it to work right for some reason. :(

The shutter isn't firing and it should be, plus the steppers aren't behaving right. Not sure if it's the code that's wrong or I've done some stupid wiring fault when soldering it all together.

Yes the pan axis should be very solid but it's a bit heavy. It's a subaru legacy wheel bearing as the main rotational part!

Image

Image


Sun Oct 19, 2014 6:36 am
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Joined: Thu May 15, 2014 5:28 pm
Posts: 76
Post Re: My home made Rail/Dolly - ongoing project...
that is looking good too.
I know that we had loads of the reliability issues to start with and to be honest, I think that it was a combination of the code and the hardware.
Bad solder joints are certainly a nightmare for stepper drivers and I think that is why i blew up so many.
I also, for some reason, had a lot of issues when I soldered in the jumper leads as you have, no idea why though....

Image

There is where I'm up to with my system.
Raspberry Pi model B+ with GPIO ribbon cable to custom made driver interface board.
The driver board hold the 3 axis, 12v power for the steppers, 3x stepper connections, Raspberry Pi Power LED, switch connection that is our soft switch to power off the Pi (hold down for 5 seconds and the Pi runs a shutdown script and
limit switch connections for the 3 axis.

You can see my tilt axis there too with the stepper motor half built too.
The bottom of the tilt axis will have a QR plate integrated so that it will fit to the rotating part of the pan axis, which will be exactly the same as the tilt axis.

I think that the pan and tilt is pretty much done now, just need to test them really.
The dolly is all but done, but Im still adjusting the dolly cart so that I can make it without having to manually adjust anything, that will make it much easier and faster to make multiples.

I though of car wheel bearings, but couldn't bring myself to accept the weight trade off :-)


Sun Oct 19, 2014 12:33 pm
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Joined: Thu Jul 24, 2014 4:52 am
Posts: 83
Post Re: My home made Rail/Dolly - ongoing project...
Sorry for the slow reply!

That looks great. I like how the other axis is progressing too. You're right about the wheel bearing weight. Might change it in future to use something lighter like a needle thrust bearing.

Progress report anyway...

Got the geared DC motor fitted in place of the stepper.

I also got all my electronics combined in a (relatively) neat control box:

*Battery pack
*Pi and Touchscreen
*Voltage regulator for the pi (12v > 5v)
*Motor driver circuit
*Shutter control circuit
*PWN controller for dew heater
*Main power switch for Pi
*Power switch for dew heater
*Potentiometer for dew heater control

Wired it all together and found it works great for the rail and shutter control just as it should. Great! I can finally do easily controlled night lapses, and set up the interval and rail movement by touchscreen. Lovely!

Problem is, the heater. I turned that on at the same time, and after a while thought
i) This isn't really warming up much, and
ii) The motor on the rail sounds a bit wheezy (was actually moving ok).

Eventually turned the heater off, and suddenly the motor made a more healthy noise.

So I've concluded that there's not enough oomph coming from the 8AA battery pack for the whole lot together.
Now I've no idea if this is just the amount of discharge rate from alkaline AA cells, or from the way it's wired. But I can't see that the wiring would matter the way it's done.

So now I need to reconsider the power requirement.
I think for now I might separate the wiring for the heater and add a lipo battery from one of my RC models to cope with that.

Interested on thoughts on what might be best though. Surprised to find this is the case since the heater will want a fair bit of juice, but I've taken the constant draw of the stepper motor out of the equation so.....


Fri Nov 07, 2014 5:38 am
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Joined: Thu Jul 24, 2014 4:52 am
Posts: 83
Post Re: My home made Rail/Dolly - ongoing project...
Sorted!

I've separated the wiring for the heater now, and fitted a deans connector so that I can plug n one of the lipo battery packs I use for RC models.
Shame that the control box was built for housing the 8AA pack and electronics before I'd fully tested it all ran well on that supply but never mind. It's just a crude box to keep all the workings together so it's still fine if I have to tape a lipo on the side! Might fit some velcro on it or something.

But anyway, with the separate battery pack the heater and motor all work fine now, and I can just unplug the lipo battery for daytime work where it's not needed.

Image


Sat Nov 08, 2014 6:43 am
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Joined: Thu Jul 24, 2014 4:52 am
Posts: 83
Post Re: My home made Rail/Dolly - ongoing project...
Just need a clear night for testing this now. Might happen one day I suppose....!


Thu Nov 13, 2014 2:40 pm
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