Timescapes - Digital Timelapse Discussion

DIY motorized/timelapse head
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Author:  Dmax [ Sat Oct 02, 2010 6:12 am ]
Post subject:  DIY motorized/timelapse head

heres a few pictures of a motorized head I'm building , Im not following any plans and just making it up as I go along so I hope it will work when its done.

the camera mount is from an old tripod I had laying around. I made a simple slip ring using copper wire to feed the tilt motor and infrared led to trigger my camera you can see this running round the base. the LCD will display info and you will be able to set the amount of shots, how long between each shot and a few other things. I'm thinking of fitting a socket so I can plug a PIR into the unit and get that to trigger the camera just incase a want to go out and take a some wildlife shots.

I was going to use stepper motors but as I had two small Dc motors I'm using these with a opto counter from an old microsoft mouse so the micro controler will know where it is.

I've fixed a screw mount so the unit can be fitted to my tripod.

here you can see one of the opto counters there is also one more that you cant see in the picture to tell the micro when its done one revolution.

and heres a picture showing the picmicro,sitting on top of that is one of the H bridge circuits but I will changing this with a IC to save space.

I have the basic code up and running but still have a lot to do. the unit triggers my nikon camera with a infrared LED but it will also have a socket to fit other camers.
I hope to have it ready in a few weeks, right now Im waiting for some H bridge Ic's to come in the post. I will post up a video when its up and running.

Thanks for looking :)

Author:  Dmax [ Sat Oct 02, 2010 10:02 am ]
Post subject:  Re: DIY motorized/timelapse head

as I've never used a time lapse rig before Im not sure about what I should get my code to do, I mean what features should this unit have, this is the sort of thing I'm thinking of going with there will be 5 steps and in each step you will be able to program the pause time and amount of shots taken,, see below .... what do you guys think ?? am I on the right track or would some other funtion be handy , I would love some feed back on this from someone that has used a time lapse rig as I'm about to get into the programing in the next day or two and it would.

step 1. Lead-In take static frames at the front of the shot by set amount time
step 2 Ramp-Up, move the camera from 0 point up to full speed and at the same time take shots by the set amount .
step 3 constant speed portion taking shots by the set amount
step 4 Ramp-Down move the camera from full speed down to 0 and at the same time take shots by the set amount
step 5 lead-out take static frames at the end of the shot.

thanks for reading and I hope someone can give me some feedback on this subject :)

Author:  milapse [ Sat Oct 02, 2010 11:28 am ]
Post subject:  Re: DIY motorized/timelapse head

Very cool! Are you familiar with openmoco? Developed by hardcore time-lapse shooters over the course of two years & open source!

Author:  Dmax [ Sat Oct 02, 2010 12:08 pm ]
Post subject:  Re: DIY motorized/timelapse head

no but I will look in to it thanks for the heads up :)

Author:  Dmax [ Tue Oct 05, 2010 9:34 am ]
Post subject:  Re: DIY motorized/timelapse head

80 views and just one reply ? have I posted in the wrong section ?

Author:  astronomerroyal [ Tue Oct 05, 2010 10:37 am ]
Post subject:  Re: DIY motorized/timelapse head

Dmax wrote:
80 views and just one reply ? have I posted in the wrong section ?

Well, I wouldn't say it's the wrong section but there is a 'Timelapse Motion Control Systems & Dollies' section. Setup & Rigs is more of a showcase section.

Some thoughts:

I like your panning section. I'm not sure about the tilt axis. Is it stable?

Ramping is a good feature, but to achieve this I would say that the mechanism should have something like 0.01 degree precision. Maybe you can achieve that, since you're using encoders. I didn't know about the encoder in old Microsoft mice. Do you know what type of mouse I should look for if I want to savage that part?

What language are you using to program your 16F uC? Assembly? I moved to 18F parts (18F4620 and 18F2620 are favourites) to benefit from Microchip's free C compiler, floating point math libraries etc. For example, I use the hyperbolic tangent for ramps, rather than linear segments. The linear ramp - if that's what you're doing - is fine, but has a discontinuous first derivative, which can sometimes be seen in the end footage. Tanh has continuous derivatives.

For anything other than very simple interfaces I like using simple 4x4 keypads. Can't remember if it's the same on the 16F87x family, but I just stick it on PORTB and use the interrupt-on-change feature. Really simple.

Also, pay close attention to periodic error in your mechanism - personally I think this is more of a problem than backlash (more frequently discussed). I went to great trouble building a pan-tilt head, and for the most part it was a success, however it had a very subtle pulsing to its motion. Over time this became fairly irritating.

Author:  Dmax [ Wed Oct 06, 2010 9:27 am ]
Post subject:  Re: DIY motorized/timelapse head

first off let me say sorry for posting in the wrong section guys.

Thanks for the info astronomerroyal thats a great help :) , the tilt axis has a small amount of backlash but Ive got a worm gear I could use maybe this will help?. The motors I'm using have a set of gears built into them, not sure what the ratio is but I can get the movement down to a very small amount, infact to the point that the only way to see it move is to put a laser pointer on the unit and have it point at a wall if you knwo what I mean,this is my very first go at anything like this, I'm use to building music synthesizers and out board gear for me its about the whole building and getting it working that I love once I got the code up and running I will spend some time fine tuning it best I can Im programing in Assembly , I know a bit of C but never programed a pic using it , I have two 18F442's but I'm using a 16F877 for this project ,not sure if the 18F442 would be any better for what I'm doing here ?. as for the encoders I'm using, most old mouse's that use a ball should have the encoders inside :). as for the interface I may add a rotary encoder if need be, I do have a 3x4 keypad but I want to keep the whole thing as small as I can as I dont drive it needs to fit in my ruck sack.
"periodic error in your mechanism" I'm not 100% sure what you mean by this and "discontinuous first derivative" would you mind telling me what thats all about as I will be coding using a linear ramp, sorry to sound so dumb but I was never that good at math at school and never had to deal with anything like this before. I need to have a good read up on all this stuff thats for sure. if you could recommend anything I could look at that would be great.

again thanks for your input astronomerroyal it all helps.

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