Project Otto Session 4

Its been a busy but awesome weekend. 🙂

 

New Lens Ring

First off, I am really excited about this thing. A while back Kyle had printed up some lens collars for me. The idea was to mount the lens to the 15mm system instead of the camera body.

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Focusing is a bitch to do. One of the main reasons is there is always SOME degree of slop or play in a lens mount. when tugging the focus ring back and forth the lens will shift ever so slightly but it is MORE than enough to show up on a timelapse.  I have several macro lenses that I timelapse with and the focus ring is very stuff. So to combat the lens shift the lens itself is mounted to the 15mm system, and the camera attaches to the back. That worked pretty well, but still was not perfect.

When playing around with the 6D, eMotimo, lens apparatus, dragonframe, I had set it up as such. In order to lock in a very tight fit i used some copper wire and a eye-screw and wired it down so the lens apparatus had a very tight lock. But seriously, it looks stupid. But it worked like a champ for my focusing testing.

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I ended up sending Kyle a sketch to see if he could modify the design and reprint. And Kyle that glorious bastard did it in Safety-Orange, which I think looks absolutely badass.

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He had actually added the 15mm support on the wrong side, but after installation it will work out fine.  The Lens apparatus has an amazing level of contact with the lens now. There is no perceivable give between the gear and the lens ring.

 

 

 

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Using a fairly short 15mm rod. Everything is a nice compact form.

 

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And to top it off, Kyle put a window in the lens ring so you can see the focusing scale.

Another great thing about this is is that since all the hardware is on the lens itself, I don’t have to deal with the added height of 15mm rod system under the camera. I really would not want to deal with that extra height on this rig. This really made my day!

 

THE POWER BOX

Beware this is getting geeky.

Managed to put the power box together.  First off lets explain what this is and why I need it.

For this setup to work you have to power the motors, and you have to be able to chop that current into various patterns to get the desired response from the motors. If you just apply power they motors will get damaged.  These are not like DC motors that just spin when you apply power, rather you instruct them as to what you want its position to be. For this to happen you have to use whats called a “driver”, which is basically hardware designed to manipulate stepper motors.

So thats what this box will be used for. It comprises of a pair of 36 volt 16 amp power supplies, which power the 10 Stepper Drivers. Each driver can control a single motor.

So the Laptop is used to build the movements out in some pretty awesome stop-motion software from Dragonframe. . That plugs via USB into the Dragonframe DMC-16. That piece of hardware is what is responsible for lighting control and motion. On the motion side it can send signals to up to 16 stepper drivers, and one motor per driver.  It uses RJ45 (ethernet) cables to connect to this new power device to send the step(move)/direction signals to the Drivers.

Laptop –> DMC-16 –> Driver –>Motor.

The Build.

It went surprisingly well.  I had picked up a server chassis to use to house the power supplies and drivers. It was a bit bigger than I expected but it has great ventilation and a solid build for about 80 bucks.

I had to play around a bit to figure out how this was going to be laid out. I kept the drivers in parallel and behind the fans on the front of the chassis to help cool them.P1770047

 

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I had picked up some wall plays for RJ45 connectors and they would fit fine right behind the slots, a few cuts later and a little file work…

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Next I needed to be able to mount the jacks for the motors.  Using some 2 inch aluminum stock Measured it up, marked it out, and had to drive to Ace Hardware because I did not have a 5/8th bit. Damn thing cost me 20 bucks. That was Trip 4 I think.

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PRO TIP. Put painters tape on the aluminum and make your markings on the tape to keep the plate looking nice.

The aluminum stock was also purchased at Ace Hardware on my 2nd trip. P1770054

The plate measured, cut and drilled. After I got all the plugs attached in I used this fantastic glue called GOOP.  I seriously love this glue, it sticks to damn near anything and is like a super sticky rubber cement. It never hardens brittle and has some crazy grip.  I used it on both RJ45 panels and the aluminum panel.

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Next I went in and drilled and tapped the sub-bottom after marking various spots so I could mount the stepper drivers and the power supplies with screws. That bottom panel comes off making it easy to modify it as needed

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Once everything was installed and bolted in it was time to start dealing with the wiring. That was a real pain in the ass. This shitty 4 wire telephone cable I got from Ace Hardware it did not want to strip and the copper was pretty brittle. It was a real bitch to deal with. I probably spend close to 4 hours just wiring.

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The voltage regulator is basically just used as a super simple fan speed control. It just takes a 36v feed off one of the power supplies and reduces it to 7 volts to keep the fans running.

You cant really see it in the pic, but each of the drivers is numbered,  and I split them across two power supplies. Even numbers on one, Odd on the other. If needed down the road the thing is rigged up for 12 drivers. I am only using 10, but if i need to expand later I can virtually just pop them in.

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The back end looking pretty good to me. Not huge on  the plastic ethernet panels, but they will certainly work and are very secure.

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Finally done wiring the damn thing and it was time to turn it on. I checked the voltage and everything looked in spec, so I wired up the first row of drivers, turned it on, and nothing exploded. I powered up the other side and got to testing.

During testing I discovered I could drive a motor off all off them but 3, 5, and 7. Checked the wiring and that shitty house telephone cable had a couple leads that broke. I had to re-terminate them but everything checked out after that. A few min later and all 10 are working as expected

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Now that everything is tested, I closed it back up and started experimenting with the stepper to see what sorts of speeds i could reach. Everything seems to be working well!

Here it is in all its glory, closed up and ready to make some awesome shit happen. I really could not be happier with how well this went together.

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Next its time to address the systems frame, figure out to mount the PTR,  how to get the z axis going.

One thing at a time.

 

 

 

 

 

 

3 thoughts on “Project Otto Session 4”

  1. May I ask what stepper drivers you are using?
    I recently bought the DMC16 and am looking at which stepper drivers to use for expanding the rig.

    Cheers
    John
    Melbourne Australia

    1. Hi John,
      I am using two types right now, Leadshine DM432c’s and CWD556’s. The leadshines are much quieter and smoother but dont hit the same speed as the CWD556 drivers. Just about any stepper driver should work though 🙂

      1. Thanks so much for the info.
        Looks like they wire direct to the differential outputs of the DMC16 without circuitry in between, just what I’m after!

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