Arduino + Slide Projector

I’m trying to determine the feasibility of using an Arduino to control the forward/reverse slide control on a Kodak Ektagraphic AMT III slide projector.

I’m working on a project that involves projecting some slides. I don’t have enough slides to fill the carousel, and this particular model does not have a “zero position locator” which would allow the machine to reset to the beginning.

I want to avoid projecting empty slots in the carousel until it gets back around to the beginning. So I was thinking that maybe I could splice into the remote control of the projector, and plug the wires into my Arduino. I could write a simple program to advance forward through the presentation, and then backwards to the beginning point and repeat.

I’m not sure if this is possible or how I would do it, from an electronics point of view. I’m also not sure how to tell Arduino to send a pulse to the proper place to advance or reverse the carousel.

Here’s a link to the operating manual of the projector I’m using:
http://www.kodak.com/global/en/service/slideProj/ektagraphic/ownerManual/ektgToc.shtml

Here’s a link to the wiring diagram:
http://slideprojector.kodak.com/plugins/acrobat/wd-amt.pdf

Could anyone help me figure out if this is possible and how I would go about it?

Thanks!

Splicing into the cable remote (or picking up the signals from the special application receptacle connector J3) isn't the big thing. On the remote, you need the pins 5, 3 and 2 where you either connect 5 to 2 (Ground) for forward or 5 to 3 (probably 24V AC) for reverse. If you want to do it in a safe way, get some small relays. If you want a fully electronic solution without relays, you should first check what kind of voltage and current you have on the pins.

Then write a small program on the Arduino which switches either relay on for a moment. Start out with a tutorial about solenoids to learn how to properly connect relays and control them, it's a good beginners task.

The main problem is how to figure out, that the slides are all through and to start reversing. Worst case, the Arduino will have to be told that this was the last slide and after this it will drive blindly by counting up and down. This can be done with a simple additional button to tell the Arduino to reverse direction now. after this, the Arduino will always reverse at this point.

On the whole, the project is cheap (Arduino, 2 relays, 2 diodes, 2 small transistors, 4 resistors and an button or two) and it's fairly easy to achieve something. If you need to get more fancy and encounter problems, you can tackle those once you have the basics running.

Korman

Thank you both for your replies. There's certainly enough for me to get started.

I should clarify that I'm certain my projector doesn't have the "zero position locator" function. That feature is available on the Ektagraphic III E Plus and Ektagraphic III A. I've got an Ektagraphic III AMT. Mine does have the 9-pin "special application receptacle", but would the pin for the zero locator still be usable if that feature isn't included?

For my purposes, and given a relatively short window of time to accomplish this (plus my lack of experience), I think I need to use the most simple solution: relays, diodes, resistors, transistors, etc. I actually have all that stuff laying around, and I might be able to figure out a general schematic after some reading.

That said, I wanted to mention that I'd like this project to run automatically. The projector will be mounted from a ceiling, and I'd like it to cycle through the slides and then back without any external input. If I'm not mistaken, I can write a simple program that will send a pulse to the projector, and connect the appropriate pin to ground to either advance or reverse the carousel. I figured I would use a program that blindly counts up and down, reversing at a certain point.

Are buttons really necessary or can I build that functionality into the program?

Thanks again for the advice.

Somehow you'll have to tell the Arduino when it's time to reverse. If the number of slides is fixed, you can code the number into your program. If the number varies, you will need some way to easily set it. Either you attach the Arduino to a computer and tell it the number of slides, or you add a button or two to program this.

I would do it with one button to set the end of magazine position. Press the button and the Arduino will from then on reverse at this position. Hold it pressed for a longer time, the limits will be reset startign at the current position. A second button might be useful to advance manually so that you can fast forward and don't need to watch the whole show when setting the reversing points.

Another thing to consider is how you're going to start after the power has been lost. Will the projector pick up at the current slide or will the tray position be reset. If you pick up at the current position, it might be necessary to store it in the EEPROM along with the limits. But those are details for later after the basics work. If you have a zero position locator, this would be really useful. In this case, you start in reverse until you find the zero position and then start counting.

Korman

I understand that the easiest thing to do would be to put several copies of the slides into the carousel. Unfortunately, at $5 per slide, and considering how much money I've already spent on other elements of this project, it's not possible.

I was hoping to use the Arduino to customize the advance/reverse function. Instead of setting the machine to automatically change slides every 4-20 seconds or manually advancing using the remote, I wanted to have each slide up for, say, 1 minute. Then, since there will be a fixed number of slides, I thought Arduino could just count one by one, and send a pulse that effectively pressed the slide advance button. Then it could delay() for however long I wanted, and then continue. If accomplishing this would require me pressing a button for any reason to control the presentation, then it would seem to make more sense to leave the wired remote control plugged in and control it manually.

So, to summarize the presentation:

-Start at slide 1 (which won't change); -Count forward by one and advance the carousel; display each slide for x milliseconds; -After slide 24 (which will always be the last slide) is displayed, count backwards by 1 and reverse the carousel, showing each slide again until slide 1 is reached; -Repeat.

I was asking about buttons because I admit I don't understand why they would be necessary (again, my knowledge of electronics is pretty limited). Based on Arduino's capabilities, sending an automatic pulse every x milliseconds and then counting forwards and backwards seemed really simple at first.

Also, this presentation will pretty much run once only, for two hours, so I don't need to be terribly concerned with potential power loss.

I hope I've done a better job of explaining what I'm trying to accomplish. I'd be happy to provide additional details if necessary.

Thanks.

Alright...cool!

The issue of buttons came from Korman's first reply:

Korman: The main problem is how to figure out, that the slides are all through and to start reversing. Worst case, the Arduino will have to be told that this was the last slide and after this it will drive blindly by counting up and down. This can be done with a simple additional button to tell the Arduino to reverse direction now. after this, the Arduino will always reverse at this point.

I hope to report back here (if this is the right place) with my progress.

Counting up and down a fixed number of slides will be fine, if there will be always 24 slides, no more and no less. The buttons are only necessary, if you need to adjust to number of slides in the field to something else. Then you need some kind of user interface, one or two buttons are the easiest.

Also, before embarking on this, make sure your slides will survive 1 minute in front of the lamp because of the heat. That was sometimes a problem, if I remember correctly.

Korman

Alrighty...a question before I order any additional components.

I looked, and I have the transistors, resistors and diodes for this circuit. I also have 2 DPDT Non-Latching Relays -12VDC. My understanding is that to use the 12V relays I would need an additional power supply besides the Arduino's 5V. I have an additional power supply, but if possible, I'd like to use just one power supply for this project: the external power supply to the Arduino.

Assuming this is possible, it would require getting 2 5V relays, right? Maybe these:http://www.sparkfun.com/products/10509? Also, would the 5V supplied by the Arduino in this case be enough to power this circuit?

Thanks.

Assuming this is possible, it would require getting 2 5V relays, right? Maybe these:http://www.sparkfun.com/products/10509? Also, would the 5V supplied by the Arduino in this case be enough to power this circuit?

That relay requires 80ma of coil current at +5vdc, so the Arduino board could power two of those relays OK. However you still require transistors to switch the relay coils on and off as directly wiring the coils to an arduino output pin would exceed it's output pin current limit.

Lefty

Great...this is all really helpful. I've placed an order for some 5V relays, and I'll be ready to try this out as soon as they arrive.

There is a ton of threads and tutorials about using relays and Arduino together, so I should be in a good spot. I'll be sure to report back with updates.

Many Thanks.

I wanted to give a quick update on this.

The relays arrived in the mail the other day, and after a bit of troubleshooting (and a quick bit of coding), the whole thing works beautifully! I found a great explanatory schematic online, and after adapting it slightly, things went pretty smoothly.

I'll try to post something about this in the "Exhibition" or "Device Hacking" sections. There's certainly nothing revolutionary in the code or the circuit, but I haven't seen many posts on here regarding slide projectors, so it may be of some use in the future.

Thanks for everyone who responded and offered advice!

Can anyone give me more info on how this is done? I am working on the same type of project (but for a photo fine art show)

My problem is though I need it to power three different projectors.

How would this work?

Would I simply have my Arduino board + two reed relays (+ mentioned diodes/transistors for protection) and then be able to run wires from each of those relays into the three projectors?

So each remote port would have 2x wires for REVERSE and 2x wires for FORWARD that then connect to the relays?

Or do I have to have actually two relays fro each projector?

They are Kodak Ektagraphic Pro III A projectors.

There is a zero position locator switch on them. I want them controlled lock-step in sychro with one another.

Basically I want 3 projectors to at the same time change slides. They will be projecting 3 images in a sequence of a photo essay. So each would change at the same time, and each would have a total of 15 slides.

I am just starting to learn arduino, actually for this project alone. So please forgive me as my knowledge of electronics is very limited. I have done some basic electronics courses but it has been a bit of time since then.

Also would like to add that they would essentially do the same as the original poster mentioned.

Start on slide 1 of carousel. Wait x seconds. Forward to slide 2 of carosel. Continue until reaching slide 15. Hold for x seconds. Reverse 15 slides. Start back with slide 1.

I understand how to write the code.

I do not understand the aspect of powering the relays. With six relays at 5v each (two relays per projector), I would need an external power supply to power the arduino.

Would I then need a power supply that is at lest 15v or more in order to insure that if the slide projector is moving forward (aka 3 relays being used at any given switching time) it would be able to supply the 5V to each relay. Is this correct thinking?

To complicate your choices, you can use just a single relay, if it has enough contacts to control your three projectors. Here is a 12vdc one that has four sets of output contacts.

http://www.allelectronics.com/make-a-store/item/4PRLY-12/RELAY-4PDT-12-VDC-KH-STYLE/1.html

But first you need to decide how you are going to power your arduino board, then the relay choices get clearer. I’m a fan of those low current 5vdc relays, the kind that KE7GKP posted links for. Just be sure the relay contact ratings are up to what the projectors require or better.

Lefty

Ok this is definitely helping.

I already purchased these relays:

http://www.sparkfun.com/products/10509

Another issue I am worried about is the arduino only has 5 outputs capable of PWM but I have six projectors. So the solution to this would I would need to use relays that have multiple output pins like the one you mentioned here:

http://www.allelectronics.com/make-a-store/item/4PRLY-12/RELAY-4PDT-12-VDC-KH-STYLE/1.html

Is that correct thinking?

Hence then the ability to use just two of these relays but with proper transistors/diodes to protect the arduino and etc?

Another issue I am worried about is the arduino only has 5 outputs capable of PWM but I have six projectors. So the solution to this would I would need to use relays that have multiple output pins like the one you mentioned here:

You won't be using PWM output commands to operate these relays, any arduino I/O pin can be set to operate in digital output mode and commanded on and off with digitalWrite(pin#, LOW); or digitalWrite(pin#, HIGH); commands. What is your thinking around using PWM commands with relays using analogWrite(pin#, value) commands?

Lefty