Slide Scanning Robot Project

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Very helpful member
Dec 11, 2014
I have been a passionate photographer for over 40 years. Like many photographers from the film era, I have many thousands of slides stored in Kodak carousels.

For a couple of decades now I have been thinking about and researching various ways to scan these slides so I can share them with the rest of my family and friends.

About three years ago I purchased a dedicated slide scanner. It does a pretty good job, but takes a very long time to scan each slide. I calculated that if I took it on as a dedicated, full-time job it would take a bit more than a year to scan all my slides.

Worse, it requires removing each slide from a carousel, inserting into the slide scanner tray, blowing dust off of it, and then interacting with the computer to scan the slide. Then I have to store the slide back away. My hands just won't cooperate enough to do this.

Over the last 3 years I have managed to scan just under 200 slides. At that rate, it will take decades to do them all. So, I have decided to go a different direction.

Now that I have all four wheelchairs in good working order, it is time for a new fun project. That project is to build a slide scanning robot. I will have the able assistance of my good friend Greg and I think we will have a great time working on this.

The basic plan is to use an Arduino microcontroller connected to a 4 channel relay. One of the relay channels will be used to control the slide projector via a hacked up remote control cord. Two of the relay channels will be used to control the camera focus/metering and shutter via a hacked up camera remote control cord.

We will remove the lens from the slide projector and replace its bulb with one that is dimmer (the projection bulb is too powerful). We will then aim a digital SLR camera with a macro lens into the slide projector to where the slide is dropped into it from the carousel for viewing.

I have done sufficient research to feel like this has at least some chance of working. I have written some prototype software that I think will control the Arduino so that it advances the slide projector one slide, turns on the camera's metering, and then fires the shutter (with appropriate delays so vibration settles out).

Based on this research, I have placed orders from various online retailers for the bits and pieces I think will be necessary to make it work.

If it works, I think it will be able to scan an entire tray (140 slides) in about 5 minutes with no interaction from me except to mount the tray on the slide projector and turn on the Arduino controller.

This is new territory for me. I have never done anything remotely like this before, so the potential of adventure and failure are high. That is the kind of challenge I can really get excited about!

I will post here as I start putting the bits and pieces together so that others can follow the journey with me.

Wish me luck! I think I am going to need it;).

Oh this would be fantastic - how many precious memories are stored this way and time would be the biggest factor for most people! You ROCK!
This is entirely unhelpful to your cause, but my dogs came up with an unexpected solution for dealing with our myriad slides a few years ago.

I look forward to seeing what solutions you cook up for your excellent project. And hopefully maybe see a few of your always amazing photos.


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Thanks for the encouragement, Tillie.

ShiftKicker, I have often thought that such a tragic end to my slides would actually be a great blessing to the relatives I am eventually going to leave behind;).

I know that few, if any of the scanned slides will be of great value to others. But, I will probably enjoy looking at them a bit.

The real purpose of this project is to explore creating circuits and using a microcontroller and relays to properly control peripheral devices. As I wrote earlier, I have never done anything remotely like that.

Today's update is that I was surprised by Amazon packages arriving:). They contained the Arduino microcontroller along with electrical components and breadboarding equipment. It was sort of like Christmas all over again!

This evening I was able to get the Arduino connected to my computer, install the Arduino Integrated Development Environment (IDE), run several sample programs provided with the IDE on the Arduino, and then load my prototype scanning program on it. The great news is that everything seems to be behaving as intended so far.

I don't have the relay module yet (and don't know when it will arrive), so I can't make a lot more progress on the control side of things, but am very pleased with what I was able to do today.

I also put together a circuit on the breadboard that will mimic the slide projector and camera operations. When the relay module arrives, I should be able to connect it to the Arduino and the breadboard and run my program. A set of LEDs on the beadboard should light up to indicate successful operation of appropriate relays.

I made a few boneheaded moves doing that, but eventually figured things out.

Now I will impatiently await the arrival of the relay controller.

Exciting! I can not wait to see it in action (you will post video of it?). I wish you joy in your intellectual/technical challenge. It sounds like things are moving along quickly.
Hey Steve, get that idea on paper and patent it.
Absolutely you have to patent this (future income for you and then your wife?), and we want video to see it in action for sure.

I can imagine how much like christmas it was getting that first package and then boneheading towards success! YAY! :!:
Thanks for all the encouragement.

Unfortunately, it is too late to patent this idea. In fact, the idea is not really mine at all.

My research found a couple of folks had posted youtube videos of taking pictures of slides from their scanners. While some details were provided, most were missing. So, I have to invent most things from scratch.

In addition, I stumbled across a company that used to sell a contraption to do exactly what I am trying to do. It cost around $4,000. Apparently, they are no longer in business. I have not found any of their units used.

My recent progress is to learn a lot more about projector bulbs. One source indicated that the stock 300 watt bulb is too bright for scanning and recommended a 35 watt bulb instead.

I researched the type of bulb I need and ordered them. Of course, the minimum quantity to order was 6. When the bulbs arrived I tried to install one and found that it would not fit. Apparently my research was faulty and I ordered a bulb with the wrong base (I got GU5.3 and I need GY5.3). Don't believe everything you ready on the internet, I guess:). I also need one with a dichroic coating and that does not have a lens cover. Who knew?

I have been able to dissect the projector remote control and test how I will need to connect the wires to the relays.

I have also cobbled together a lens arrangement that will allow me to shoot close to a full frame of the slide while it is loaded in the projector and backlit by the projector's bulb. The solution is an 85mm f1.4 lens with 4 extension tubes (a total of about 62mm of total extension (this allows the lens to focus closer and for the resulting image to be more magnified).

I still don't have the relay module and I still need to figure out something to do about the projector bulb, but think I am making progress. I also need to dissect the camera remote to confirm I can fire the camera via the relays.

I am having a lot of fun doing this. I think I figured out a way to wirelessly control this with my cell phone and bluetooth, though that will take a bit more hardware.

All I can say Steve is that you never cease to amaze me! Thank you for sharing all your knowledge and even more importantly your amazing spirit. Kate
Steve this sounds amazing. I know you’ll get it and I’m excited for you to even try.


Pity about the patent, but what fun amidst the frustration!

You may end up with a few spare pieces left over by the time you finish - maybe you can invent something that needs all those other bulbs so they get used up ... :lol:
Thanks for all the encouragement, everyone!

Here is the latest update.

I have dissected the remote for the camera and found out which wires need to be connected to the relays to cause it to focus, meter the scene, and take the picture. Once the relay module gets here, I should be able to hook the remote up correctly.

I have decided to go with the stock bulb in the projector (300 watts) for the initial try. I have ordered photographic light diffusion filter material that I will place between the light and the slide in the projector. If that arrangement is too bright, I will purchase the 150 watt bulb I have found a source for.

Since I am trying to build a bit of a robot, I decided to give the system much more capability in the way it manipulates the carousel on the projector. To do this, I had to completely rewrite the software I had previously written. It was a lot of fun, filled with learning opportunities:). The software now has commands to scan all the slides in a carousel, scan just the next slide, scan just the current slide, advance the carousel one position, move the carousel back one position, and more the carousel to any arbitrary desired position (and take the short way around to do it). The software also allows scanning to be paused and resumed, as well as to be restarted from the first slide in the carousel. There is also the capability to go to a desired position in the carousel and scan a specified number of slides. This is all way more than is needed, but has been a lot of fun to develop.

Part of the reason for writing more sophisticated software is that I remember the old, cardboard-mounted slides tend to occasionally jam in the slide projector. So, I need some flexibility in telling the system which slide to scan as I recover from a jam.

It was a bit of a trick to fit the software into the limited memory of the Arduino microprocessor. The Arduino version I am using only has 32 KB of flash memory, 2KB of SRAM (yep, just 2048 bytes), and 1 KB of EEPROM. There is no DRAM. All the program variables, logging message strings, etc. must fit into 2KB. That is about 1/16,000,000th of what my laptop computer has available for storing such things. And the laptop's memory is virtual. The Arduino's memory is not.

I have also been investigating wirelessly controlling the scanning robot using bluetooth. I have ordered a bluetooth module (less than $10) from amazon and have developed an app for my android phone that might be able to control things. We will see if I can make that stuff work.

I am beginning to be optimistic I can make the thing work. We are still anxiously waiting for the relay module to arrive by slow boat from China. It was literally ordered from china and based on the estimated delivery date must be being shipped in a cargo container on a very slow boat.

The great news is that so far no humans or pets have been harmed and the house has not yet caught fire:). My friend Greg and I have had wonderful times working on this.

My relief that no animals were harmed in the production of this is vast! :lol:

Love your updates!
Awesome update. Don’t understand it all, but I do feel the excitement through the computer. I know this whole project has to make you feel so good.

Keep it up :)
Sounds like it's a great project. Best wishes. I'll keep up with your progress posts.
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