It is currently Mon Sep 21, 2020 11:04 pm




Post new topic Reply to topic  [ 4 posts ] 
 New to timelapse - please evaluate my linear controller.... 
Author Message

Joined: Mon Apr 18, 2011 6:19 pm
Posts: 8
Post New to timelapse - please evaluate my linear controller....
Hi Everyone.

I'm just starting in timelapse. I've done a few with no motion control, but nothing worth posting yet.

I was able to grab some spare parts from an old metal lathe and turn this into a linear motion controller.

There is a mount that travels on 2 rods, and a leadscrew that goes down the center, attached to a stepper motor.

I don't have this mounted on anything yet.

See pics....

My question - this is giving me about 18" of travel and the slowest speed will cover 18" in about 3.5 minutes.

I'm wondering if this is OK. I'm thinking that this is awfully fast. If I want a movie that is 24 frames per second, and I'm taking a frame per second, I'm only getting a movie that's 8.75 seconds long.....

Thoughts on this speed? I'm a machinist, so I can certainly get a longer leadscrew and rods and make them work, but even if I double the length, I only get 16 seconds.

The other option is a slower stepper motor, which might be best.

Thoughts?


Attachments:
IMG_2722.jpg
IMG_2722.jpg [ 105.44 KiB | Viewed 1808 times ]
IMG_2721.jpg
IMG_2721.jpg [ 113.66 KiB | Viewed 1808 times ]
Fri Apr 22, 2011 5:28 am
Profile

Joined: Mon Jul 19, 2010 1:52 pm
Posts: 72
Post Re: New to timelapse - please evaluate my linear controller....
8.75s is a good length for a single TL clip, you will probably edit it down anyway, 4-6s is a good average. At 30fps (which is more standard I think) you end up with 7s. Also, a travel length of 18" = 45cm is a good start although for many subjects you probably want to be able to cover a longer distance, twice that amount and up. Then with the same speed to also get double the time which gives some more freedom.


Fri Apr 22, 2011 10:39 am
Profile
User avatar

Joined: Tue Jul 08, 2008 12:36 pm
Posts: 1787
Location: Antarctica/California/New Zealand
Post Re: New to timelapse - please evaluate my linear controller....
Depending on what you are shooting you will probably want to be able to go a lot slower. I think about the shortest time-lapse clips I do that don't involve people usually don't go much less than 10 minutes.

_________________
Anthony Powell
"Antarctica: A Year On Ice" Feature Film
Vimeo Youtube Photos
Twitter Instagram Google+
Facebook Facebook Movie Page


Mon Apr 25, 2011 1:21 am
Profile
User avatar

Joined: Wed Nov 11, 2009 10:45 am
Posts: 1685
Location: Merritt Island, Florida, Estates Unitas
Post Re: New to timelapse - please evaluate my linear controller....
Great work! That has to be the most precise, robust dolly ever. An easy way to slow it down would be to switch from continuous motion to some sort of shoot move shoot mode. It doesn't have to be complicated. Does it move freely enough to drive with a little Dayton gearmotor like the Dynamic Perception dolly? If so, just the motor and an MX-2 dolly controller would do it.

If you really like the motor you have, or if you need more push than the 1Amp motors can provide, use a relay. Run the MX-2 in interleaved mode (what they call shoot move shoot). Connect an electromagnet type relay to the motor output of the MX-2. The MX-2 should power the coil of the relay. Now cut the signal wire for the stepper motor and solder the ends to the switch connections on the relay so the relay switch can interrupt the pulses sent to the stepper. When the MX-2 wants to turn the motor on, it energizes the relay coil and the relay makes the contact between the stepper motor and your stepper controller. When the MX-2 wants to turn the motor off, it stops powering the relay coil and the relay interrupts the pulses from your stepper controller to the stepper motor.


Mon Apr 25, 2011 5:08 am
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © phpBB Group.
Designed by Vjacheslav Trushkin for Free Forums/DivisionCore. pozycjonowanie