DSLR Intervalometer with Arduino Uno

Using Arduino Project Guidance
#1

Hello All,

I just recieved my first ever Arduino Uno Starter Kit. It’s really nice, with a motor, breadboard, jumpers, etc. Just letting you know I have a fairly large background in software(like the C languages) and now I’m getting into implementing it with hardware.

What I want to do: I want to use my Uno to make a DSLR intervalometer. It’s essentially a 2.5mm plug that goes into my camera to snap a picture every so often to make a time lapse.

My Gear:
-Arduino Uno with breadboards, wires, etc.
-Canon EOS Rebel T5i DSLR Camera (with a 2.5mm remote trigger outlet)
-2.5mm cable (that’s capable of triggering the shutter; I tested it by pressing a button

First, I found an old headset that had a 2.5mm end on it that fit in my camera. I flipped the switch on the headset and my camera started firing. So, I stripped the end of the cable. There is a red, green, and gold-ish wire. I know these correspond to some part on the plug, which when triggered correctly control the autofocus and the actual shutter. Any idea what the colors correspond to? It’s a standard 2.5mm, with two stripes.

I’m going to eventually stick this on my camera with a shoe mount in a project box of some sort, with maybe a display (which the starter kit did come with :)) to show how many have fired and the increments. That should be fairly straight forward, but I want to get the bare bones working first.

So, any ideas with this 2.5mm cable? What do the colors correspond to? How would I attach them to my breadboard and trigger them? The cables seem pretty flimsy. Also it’s probably time to point out that I do not have a soldering iron readily available, but I have read online that hot glue may work. My greatest thanks to all of you!

#2

Google will be glad to help -- for lots of ideas and examples search for "Canon EOS Rebel remote control circuit"

#3

Well the pinouts are fairly simple. Here is a list of the pinouts of the various camera's cables: http://www.doc-diy.net/photo/remote_pinout/

As you can see, the 2.5mm cable has 3 wires. The one closest to the cable is the ground, the middle one is the focus, and the tip is the fire control. If you connect the ground wire to the middle wire, it should cause the camera to focus (do the 1/2 press of a shutter release). On some cameras, you will need to connect the ground to both the focus and fire wires to shoot, on some you only need to connect the ground to the fire wire to shoot. It is fairly easy to use a metal wire or even screwdriver to determine which method your camera uses (my Olympus cameras need both connected).

The basic idea is to have one pin on your Arduino that connects the ground to the focus wire, and another that connects the ground to the fire wire. I use an opto-coupler so that the Arduino is electrically separate from the camera (the camera provides a weak current through the wires, and when the circuit is completed, it does the action). You probably could use transistors instead of opto-coupler, but I started with an opto-coupler, and I prefer the extra layer of isolation (an opto-coupler has a led inside with a photo trigger, so the Arduino and camera never have wires connected together). Recently, I've been using CNY74-2 optocouplers with 220ohm pull-down resistors, but you might want to use this unit which is more self contained: http://www.ebay.com/itm/300723438237?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649.

On the left side, you would connect a 5v wire from the Arduino to VCC, ground to the ground connection, and the 2 pins that will control the focus and fire to CH1/CH2. On the right side, you would connect the ground wire to both - terminals, and connect the focus to the CH1 + terminal, and fire to the CH2 + terminal. You would then need to write a program that uses digitalWrite on the 2 pins to control the focus/fire buttons.

If you live in the USA, and still have a Radio Shack nearby, they have 2.5mm terminals, that you plug a cable into and it has 3 connections to solder wires to: http://www.radioshack.com/product/index.jsp?productId=2103450&numProdsPerPage=60.

Typically you need to go to the back of the store to find the gray cabinets of doom, to search through for the connector. If you are lucky, the clerk can help with the search (many RS clerks have no knowledge of these type of electronics). Initially you can just twist the wires instead of soldering. Or you can just cut up a cable.

You need a tool like a multimeter (or a simple connectivity circuit that has a led with a resistor connected to a battery, and the led lights up when the circuit is complete -- you use this to identify which wire is which).

#4

If you are lucky, the clerk can help with the search (many RS clerks have no knowledge of these type of electronics).

I don’t know if you remember their ad… “You have questions. We have answers.”

I always found it was more like “You have questions. We have blank stares.”

#5

lar3ry: I don't know if you remember their ad.. "You have questions. We have answers." I always found it was more like "You have questions. We have blank stares."

I don't remember the ad, but it is kind of sad. They are trying to re-invent themselves, but unfortunately, I'm not sure in the day of ebay, whether they will be able to survive. And getting skilled clerks is a problem....

#6