View Full Version : Time Lapse Photography with the Propeller?
Is there a way I can set up a camera (webcam or standard digital) to take photos every 30 seconds?
07-11-2009, 03:20 AM
take a look in the completed projects area - there's a recent one there... don't recall if it's prop-based though.
07-11-2009, 07:05 AM
adri, you can do that with a 555 timer a lot cheaper. The main thing is interfacing your timer to the camera so it can trigger the shutter release.
07-11-2009, 08:09 AM
I have built time-lapse controllers with 555s, but those only work with cameras that take a simple input (hard to find these days). I built the controller referenced above using the SX because I wanted precise, repeatable control and my camera (Sony DSC-H7) only takes IR input (20-bit SIRCS code). I have ported the SIRCS transmission to the Propeller and I will change out the processor soon. I'll also add more features, too, such as shooting a specific number of frames or shooting within a designated time window (I'm adding a battery-backed RTC chip to the design).
Timothy D. Swieter
07-11-2009, 09:27 AM
Something that has been in the back of my mind is using a Canon digital camera, just about any type, and the Canon Hack Development Kit to reprogram the firmware of the camera. One of the features of the reprogrammed firmware is that you can trig photos by placing a voltage on the USB port. Of course, you need to design the circuit right, but you could do this with the Propeller or SX or Basic stamp.
Timothy D. Swieter, E.I.
www.brilldea.com (http://www.brilldea.com) - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
07-11-2009, 12:49 PM
I have found a variety of circuits on the web. In my SX-based design I'm intending to design in a "personality module" that will tell the Propeller what it is so the Propeller knows how to output a shutter command to the camera.
07-11-2009, 07:28 PM
If you do not want to HACK your camera you can use a SERVO to push the button.
My Nikon D80 has an infra-red sensor that can be used to trigger the shutter. Nikon actually makes a remote control that uses it but some people have built their own, IIRC.
I've just noticed that the shutter can also be controlled electrically with a cable. That would be much easier for time-lapse photography - a transistor switch can be closed with an MCU.
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Post Edited (Leon) : 7/11/2009 2:41:17 PM GMT
07-11-2009, 09:19 PM
Why hack into a nice camera? SamMishal is quite right.
I have a black plastic chassis box inside which I mounted my the camera using it's ordinary tripod mount screw. Also mounted in the box's backside is a R/C servo. I have carved a cam from a servo arm that simply depresses the button. Admittedly, it may seem a little bulky, but it does allow one to protect the camera from the weather as well. All I have to do is to tape a glass pane to the front of the box.
There is even room in the box for a 7.4 Lithium battery and a BasicStamp board to drive the servo.
And so I wonder why I might need 8 cogs of Propeller Power for this one task. I've considered having a photoelectric sensor that shuts down the unit when ambient light is too dark. This would obviously save power when it is usless to photo without flash. But a BasicStamp can do that as well. Similarly, multiple triggers could be provided by a parallel to serial shift register input if 15 pins are not enough.
It would certainly be nice if someone manufactured a camera with an intentional hacker's interface. We would all buy it.
About the ONLY context in which I could imagine using the Propeller to trigger a camera would be for a very precise trigger in laboratory work. And it it could do high speed multiple triggers, all the better. That would really rock!
Ain't gadetry a wonderful thing?
aka G. Herzog [ 黃鶴 ] in Taiwan
Post Edited (Loopy Byteloose) : 7/11/2009 1:30:08 PM GMT
07-11-2009, 10:55 PM
Use a servo to trigger a camera shutter is a bit of a caveman approach, and in an application where you might be running from batteries over a long period the servo is going to be a bad idea; in addition to the trickery of the mechanical interface you have a power hog. No thanks. For my present (SX-based) intervalometer that uses Sony IR to transmit the shutter code I use a stick-on IR transmitter that is designed for VCRs to control cable boxes; very clean, very low power.
You could apply the "Why use the Propeller?" to anything; hell, why did Parallax bother creating the Propeller when there are so many other good micros on the market? Because it might be a better approach. My intervalometer has an LCD user interface so I can set the frame timing and see what's going on. Using 32-bit numbers my next version will do the frame calculations for me; I'll enter the real-time duration, the intended screening time, the screen rate (usually 24 or 30 fps) and let the Propeller calculate the interval between frames. Sure, I could do this on the SX as well but I'm already running short of programming space on the SX28 and instead of bumping to the 48 I'm going to bump all the way up to the Propeller. In the end I'll have more and better features and the coding will be easier because I don't have to work at managing interrupts.
07-12-2009, 03:44 AM
We have hacked several cameras for balloon shots, using a prop controller. In all 4 cameras so far there is a DPST switch that must be controlled in a two step sequence. We used a pair of 2N222 transistors to switch power to two small relays that connect to the two pairs of switches. It works, but soldering to the original camera contacts is not for the faint of heart or for aged eyes. Once the wires are mounted to the camera switch, we gob on enough epoxy to make sure that the fragile contacts survive some mechanical abuse. 1-2 seconds delay between the two closures is enough for the camera to do whatever it thinks necessary prior to the final picture activation.
Not pretty, but it works. With a bit of case-shaving to accommodate the epoxy blob, the original button function can often be preserved.
07-12-2009, 03:58 AM
@JM: Looking forward to seeing your Prop version too.
This has application in astro-photography. It's also time lapse, but the end result is one image. We take many exposures over time of the *same object* and overlay them. It's perfectly normal to take in excess of 2000 shots over the course of an observation period of multiple hours. It's also standard practice to take >10,000 shots over the course of several days synced up to the same object each night The software takes a subset, the best of, and blends them together. But there's another aspect - we use filters.
You see, we don't see colors well in the dark. And the colors objects radiate or re-radiate are often very weak and subtle. The way to get these colors to pop is via filters. Think RGB (and sometimes Y and uV or IR:) In one 'star shoot' session, you might take 500 images each through Red, then Green, then Blue, etc. The software takes the best of each set, and merges. The filters are on a wheel and are usually manually rotated in/out. Recently, automated filters have become affordable.
Both the SX, better the Prop, versions could control all aspects of such shooting, including other things I've not mentioned.
Post Edited (CounterRotatingProps) : 7/11/2009 8:21:51 PM GMT