First time here and new to arduino need advice please

Hi I am new at all this even if I am 55 I have 2 projects I want to build would love to do then in one unit if possible.
First one is a stepper motor controlled focusing rail (for photo stacking ) I know it has been done before just can not find instructions.
The other is the camera axe I have found that here is my problem cash is very tight if I can build both units together it will help. I can figure out the program if I have to I have been off work for 2 years now with I'll health (very bad depression) so time not a problem. But can only afford to buy the bits once I have a nema 17 stepper motor. If some one has time could they give me a list of what to buy and the best place to get it from please also any links or advice on circuit diagrams would be so helpful.also I know it's a lot to ask but if some one wants to take me under there wing and guide me I would be ever so great full.I just need to get my life back on track and able to think again.
Albert :blush:

with tight budgets it is allways worth to check electronic scrapheaps, for anything usefull. Everything not need to be bought saves money.
Ask family and friends for unused devices, toys etc.

Where are you from? (country?) as Albert is quite international? Maybe you can join a local Arduino group?

First off Albert, Welcome to your new addiction, Arduino.. you've already got the photography bug I see :wink:

First and foremost, take a moment and read this.. it's a post of mine from earlier this year:
Arduino as a form of Therapy

I'm a disabled former programmer, and find that my hobbies (which happen to include photography and Arduino) are key in keeping my sanity. Let me tell you, I'm no stranger to what you are trying to cope with.. and keeping your mind active is the single best treatment in the world.

Now that I've said that, let me go and see if I can find you some good ideas for what you are trying to do.. and as Rob said, where are you? There may very well be one of us within spitting distance..

Hi I did not expect any one to get back to me so quick.
I am from Stockton on tees in the north east of England the idea for the stacking rail is from one called Stack shot and is here

Building the rail is mo problem just how to make it work something like the one on the sight is the hard bit.
If I can combine it with the camera axe project as well I will be so happy. I sold an old camera to fund the project just buying anything from the USA costs me another 20 percent in vat.
All help appreciated
Albert

Number one in the "good idea" department: Go to the junkyard and get yourself a dead printer. Older the better. You have just gotten 90% of your focus rail components and hardware.

Dot matrix (even inkjet) printers use steppers extensively, and include the drive circuitry for the motors. At worst, you have to use a 50 cent darlington array as a driver. An older dot matrix printer will have several CNC-grade steppers. You don't need any real power, you just need to move a carriage along a rail system.

However, I think you should instead go over to yourduino.com (note, that's a member here's store) or pretty much any place on ebay and buy a "5v geared hobby servo with ULN2003 controller board". High torque, 4000 steps per revolution (!!!) and what you are going to do is get a cheap toy car frame, step it along the rail with the stepper (the car's wheels take the weight, so the stepper only makes it roll) and you are DONE! I would place a gear on the stepper, place it 90 degrees to the rail.. and use threaded rod (its just a long bolt) as the rail. The teeth of the stepper gear will mesh nicely if you match the thread spacing with the rod. Oh yes, the motor and the driver board combined will cost you under ten dollars shipped no matter where you get it. That should help.

You are doing image stacking, so you are looking to do macro photos with a HUGE aperture, I am assuming. I'm a huge fan of the Canon F1.8 50mm prime. Wish I could afford fluorite glass, but if you can't, that $100 lens is the best $100 you'll ever spend. The lens is legendary, and you can drive a freaking bus through the thing. You will have a tiny DOF, that stepper motor will give you a ridiculous level of resolution of steps, you're going to find that we're going to need to make tens or hundreds of steps between shots to effectively shift the field...

Which axe functions are you actually needing? You probably can get away with a scaled-back version..

Old scanners can also be a good source of parts.

I have a manual focus rail and bellows I have just fitted a nema 17 stepper motor to it.
So that's sorted it's just the building of the electronics I am stuck on.
I would like all the functions of the camera axe if possible and I think a lot of the stack shot rail program is similar just need to drive the stepper motor and control it. So if I knew what I was doing don't think it would be too hard.
Albert

Well, the "right" way to do that is to modify the camera axe software, adding an additional menu item. In terms of circuitry, you are going to be able to get away with using two pins on the arduino, which I'm sure the axe design leaves open. The code changes to the existing software would involve menu for moving a motor.. but if you are trying for automation like move/snap/move/snap, you are going to need to make more extensive and complex modifications. Since I see no reason for mixing many of the axe functions with a rail focuser, it's probably advisable to skip most axe functions and instead concentrate on doing the functions we do want use well..

Yes It would be move,wait,snap move ect
I don't mind building two units if I have to as long as I know what parts to buy.
I have seen it done in picaxe here
http://www.ebswift.com/Articles/Electronics/Picaxe/MacroRail/
But would like to use aurduino as they are more helpful pepole
The bots from pick axe I want ate basically to use a broken beam sensor with a delay before firing a couple of outputs. For the water drops pictures ect
Albert

So we can skip all the other sensor functions of axe and work with those requirements a lot easier. Cool. Modding someone else's code that is that large (the axe code is several thousand lines) can be painful, it's going to be a lot easier to "roll your your own" with just the functionality you need. I'd suggest a second controller if it made sense, but since we are trying to synchronize a couple of activities, you're left with the same problem if using the existing axe code.. sending and reading external signals while synchronizing other functions.

In terms of camera control, all you really need is shutter.

Now, what we need is "pseudo code". What that means is that we need a description, in detail, of what we want it to do. In other words, we want to know step by step what the program should do. From that, we write a program to do it. You don't really need to know a thing about programming to write pseudo code, all you need to be able to do is explain the sequence of events in detail. Programming is just translating THAT description into something a microcontroller can read.

Ok here is what the circuit has to do

  1. Select mode mode 1 rail, mode 2 beam
  2. mode 1 first jog to start position (to jog at slow speed to start position but must be able to jog both ways in case you over shoot.
  3. Jog to end position same rules apply as above
  4. On button press motor drives automatically back to start position.
  5. Set step size ( this will be in around 0.2 of a mm to 1mm of movement 1 full rotation of 360 degrees is 1 mm)
  6. Set delay ( from 1 milisecond to 5 seconds)
  7. On the start button being pressed the stepper motor moves the step size set and waits the delay set then fires 2 outputs moves again etc till it reaches the end position.
    8 button press will move back to the start position.
    9 offers the option to run again or go back to mode selection.

Mode 2

  1. Set delay time as above
  2. Press start
  3. On input being tiggered ( beam broken)
  4. Wait delay set
  5. Fire 2 outputs
    6 offer option to run again when start pressed or retun to mode selection

Is this what you ment for the details
Albert

Pretty good, that's a fairly good outline. I've got to run a few errands with the kids and such, but suffice to say, that should prove to be some fairly easy coding.

The actual movement per step is going to depend a lot upon how the drive train is geared, but it sounds like it should be possible without too much difficulty. Do you happen to have the motor specifications handy? We're going to need to select a circuit for driving it.. assuming it's nothing crazy, we should be able to use some cheap off-the-shelf transistors or a darlington array as a controller. Have you selected a beam/sensor yet?

Hi again
The motor detail are below
http://cgi.ebay.co.uk/NEW-NEMA-17-Mini-Stepper-Motor-0-45-Nm-CNC-Router-Mill-/200629154973?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item2eb66df49d#ht_6936wt_965
It's the 4 wire nema 17
As to sensor I would like to use a laser sensor so its a nich small beam as a single beam or if one to much trouble 2 sensors to give a cross beam sensor for mor accuracy in foucusing

Whew.. gonna take a nice load-bearing transistor for that puppy. Actually, four.

2.8v, looks like we should be on the safe side if we overbuild the circuit to provide 2A (the motor peaks at 1.6A draw)

Now here is where I'll throw out to the better engineers: Instead of the Darlingtons I am going to recommend here (something like a TIP series) what would make a "better" choice by using a MOSFET? I understand the power loss to the transistor will be much lower, so we'll have less heat to deal with; but I don't fully understand what MOSFET I would want for this application, and if it would be a "drop in replacement" for the darlington NPN I would normally use. While I'm at it, I'll ask the question: should I be using base resistors with the darlington arrays? It just occurred to me that there isn't any in the referenced design (or in my current projects).. am I dumping a lot of current where it isn't needed?

(I'm learning here too!)

OR, I may just find him a Darlington array ala ULN2003 (which handles 500mA each)... then he can just follow the circuit references from the library directly.

Somewhere I actually saw someone who had piggybacked two ULN2003's, actually sitting one on top of the other with the leads soldered together. That can't be a good idea.

So, that's where I want you to take a short read through.. the Stepper library part of the language reference. It's not bad, pretty short, and gives a nice concise description of what we are going to be doing with that motor of yours:

The link to Tom Igoe's information is well worth the read if you are interested in the details...

Instead of the Darlingtons I am going to recommend here (something like a TIP series) what would make a "better" choice by using a MOSFET? I understand the power loss to the transistor will be much lower, so we'll have less heat to deal with; but I don't fully understand what MOSFET I would want for this application, and if it would be a "drop in replacement" for the darlington NPN I would normally use.

Yes, a beefy LOGIC LEVEL N-channel power mosfet will save you lots of generated heat loss compaired to darlingtons. Here is a nice beefy candidate for your consideration:

Also avalible included with a connector/board assembly:

Hi this is a great forum everyone is so helpful I have got started on the mechanical side hope to have it finished in a few days.
Is there any book that any one can recommend I can read to get my head around the Programing
Albert

For C, my favourite is "A book On C" by Kelley and Pohl.
However, the IDE comes packed with examples and tutorials, and useful advice is to try these, tweak and hack them to modify - tinkering is a great way of learning.

I know I am probley being thick but what's the IDE?

Sorry - the (integrated) development environment.
The Arduino compiler/editor.
If you click on "file" up, top left, then scroll down to "Examples", there's a whole load of ready-written examples.

Thank you as I am new to this I am just about to buy my first bits what would you recommend to start with and learn how to use it . Bearing in mind what I have plans to build I have lots of ideas to try out just not sure best bit to get
Albert