I decided to make a quality DIY intervalometer for my DSLR Pentax camera so that I could do time-lapse photography. This intervalometer should work with most major brands of DSLR cameras such as Nikons and Canons. It works by triggering the shutter using the camera's remote trigger port. It can also auto-focus before each shot if so desired (or toggle this on or off at any time). The brains of this intervalometer is an Arduino chip. It may seem very complicated at first glance, but is actually a simple circuit and not that hard to make.
Step 1: Go Get Stuff
You will need:
(x1) Small wood box
(x1) 1/8" acrylic panel (see next step)
(x1) black acrylic paint and brush
(x1) 1K resistor
(x1) 100 ohm resistor
(x1) LM7805 5V regulator
(x1) 2-color LED
(x1) 16MHz crystal
(x2) 22pf capacitors
(x1) 10K potentiometer
(x1) 28 pin socket
(x1) DPDT toggle switch
(x1) SPST push-button switch
(x1) M-type socket
(x2) SPST 5V reed relays
(x1) shielded stereo cable
(x1) 3/32" (2.5mm) male plug
(x1) 6VDC power adapter with M-type plug
(x1) toggle switch cover (optional)
(x4) 1" wood screws
(x1) red, black and green wire
(x1) soldering setup
(x1) drill press (or hand drill) and misc. tools.
Step 2: Make the Front Panel
If you happen to have a 70 Watt Epilog laser cutter, do the following...
Download the attached template file. Put your 1/8" white acrylic in the machine (do not remove the protective coating). Adjust the border of the template appropriately to match the borders of your box.
Laser etch the design with the following settings:
Cut out the template as such:
When you are done lay down 2 - 3 thin coats of black paint and wait for them to dry before you peel off the protective coating from the acrylic. Use a craft knife to carefully pick off the bits of covering that remain.
Okay, okay... I know most of you don't have a laser cutter. Here are some alternatives:
1) Download the file print out the design as a decal and also use the design as a template to cut out the panel with more traditional tools.
2) Screen print the design onto your surface and then cut out the template with more traditional tools.
3) Download the file and use a service like Ponoko to have them laser cut it for you to your specifications.
4) Download the file. Find a local college or machine shop like TechShop that will let you rent time on a laser cutter.
5) Download the file. Find a local hackerspace that might have a laser cutter and would let you cut the file for little or no charge.
Step 3: Wire the Plug
Get a stereo cable. I got a 25' headphone extension cable from Radioshack and cut out a 4' section from the middle of the cable to use. I will use the other two remainder parts for future projects.
Untwist the plug so that the terminals are exposed.
On the terminal closest to the actual 'plug part' solder the black wire from your stereo cable.
On the next terminal, solder the red wire.
To the big metal ground tab that extends out the back, solder the ground shielding.
Check the connections with a multimeter to make certain none got crossed and then twist the cover back onto the plug.
Step 4: Drill
Lay your front panel over the opening of your box. Use the template as a guide to mark the four corners of the box for drilling. Also make two marks on the side of the case. One of these marks is for the power jack and the other mark is for the audio cable.
Please keep in mind that the circuit board will lay on the bottom of the case and switch and knobs will be protruding from the top. Place these holes somewhere in between.
After you happy with all of your markings drill the holes.
For the pilot holes for the screws I used a 5/32 drill bit.
For the M-type jack I used a 3/8" bit.
For the stereo cable, I used a 1/8" bit.
Step 5: Start the Circuit Board
For now leave off anything that connects to the front panel and the power jack.
Basically, attach the parts and connections needed for the micro controller and the relays.
You may also want to attach a 10uF electrolytic capacitor between 9V and ground and another between 5V and ground. I thought I could get away without them, but ended up adding them because it wasn't functioning very reliably running from a 9V battery without the capacitors.
Note: in the image there are ground connections to the chip and the capacitors that you cannot see in the images since they are made underneath the board.
update 1-7-11: Astroboy907 converted the schematic into an Eagle schematic and board. These files are now attached to this step or can be downloaded from the comments below.
Step 6: Prep the Case
Fasten your power jack into the case.
Pass in the audio cable and tie a knot to prevent it from getting pulled out.
Step 7: Wire the Relay
Now it is time to wire up the relays.
Connect one pin of each coil to ground. Connect the other pins to pin 4 and pin 5 of the Arduino respectively.
Solder together two of the relay switch terminals and solder the stereo ground shielding to them.
To the relay connected to pin 4, solder the red wire from the stereo cable to the relay switch terminal.
To the relay connect to pin 5 solder a black wire, but not the one from the stereo cable. Both the black wire connected to the relay and the black wire from the stereo cable will be solder to the focus switch shortly (not pictured in the schematic).
Step 8: Wire the Power
Test the center of your 6V power plug and figure out whether the center is positive or negative.
In my case, the center was positive. So, I wired the red wire to the middle pin and the black wire to the ground terminal.
Step 9: Wire the Front Panel
Attach a red wire to the right pin of the potentiometer, a green wire to the center pin and a black wire to the left pin.
Attach a red and black wire the push-button reset switch.
Insert the two-color LED into the front panel and bend the leads to a right angle.
Step 10: Connect It All Together
Now is the confusing time to wire it all together. Of most important is the bold text. I forgot to draw this switch onto the schematic. Whoops ;-)
Connect the black wire from the stereo cable to one of the center pins on the DPDT toggle switch. Select one of the matching outer pins and solder the unconnected black wire from the relay.
Connect one of the outer legs from the 2-color LED to the other center pin (in my case this was 'yellow'). On the outer pin (adjacent to the other outer pin you have just selected), connect a wire from there to pin 14 on the Arduino.
(You should be left with a pair of two adjacent unused outer pins)
Connect the center 2-Color LED pin to the 100 ohm resistor on the circuit board.
Connect the unused outer pin on the LED to pin 13 (in my case this was 'green').
Connect the red wire from the potentiometer to the 5V power source on the board.
Connect the green wire from the potentiometer to pin 21 of the Arduino.
Connect the black wire from the potentiometer to ground.
Connect the black wire from the reset switch to ground
Connect the red wire to pin 1 of the Arduino (before the resistor)
Connect the red wire from the power jack to the input of the 7805 regulator.
Connect the black wire to ground.
Step 11: Program the Chip
Download, compile and upload the code below onto your Arduino chip.
When you are done remove the ATMEGA168 chip from the Arduino and install it into the socket in your circuit board such that the tab on the chip lines up with the tab on the socket.
Keep in mind that your Arduino board will need a new ATMEGA168 chip with a bootloader installed on it before you can use it again.
Step 12: Case Close
Fasten the case closed with your screws. Attach the knob to the potentiometer and stick on any toggle switch covers you might have.
To use, simply plug it into your camera's remote control port, dial in your time settings and then attach a 6V power adapter to the intervalometer and it will start shooting away.
Step 13: Battery Adapter (optional)
I didn't include a battery inside the case to save space and so I would not have to be bothered with a power switch or disassembling the case for battery replacement.
Instead, I made a simple 9V battery adapter with an M-type male plug, a 9V battery connector and some electrical tape.
Basically, solder the red wire from the battery connector the center terminal on the M-type plug and the black wire to the large metal ground tab. Wrap the whole shebang in electrical tape when you are done to prevent it from getting ripped apart.