First things first.
I am now on Twitter. Lets see how this pans out. Go follow me.
Yes, there is already a Biolapse on twitter. Turns out there is a musician that goes by that nomenclature. So I had to go with Biolapse Films.
I have a new gmail account for Biolapse as well. BiolapseFilms@gmail.com
I want to distance Biolapse from The Chronos Project. One is a non functioning hardware company, but Biolapse is all about filming plants and is very much alive and active.
Now, on to OTTO.
These last few weeks have been a bit frustrating. The prior week I had been on-call with my day job, and it is very invasive and consumes a lot of my time. This past week I have been hiking in the morning, working a later shift, and had not had much time to work on the project. But there is some progress since the last update.
So for those who are wondering WTF I am talking about, lets take a quick discussion into stepper motors.
Stepper motors are friggin awesome. With a DC motor, you apply current and it starts to spin. Stepper motors do not work the same way. Rather than just spin with current, they take a single “Step”
Without getting in the nitty gritty, most step motors have 1.8 degree steps. What this means, if you want the motor to make one full rotation, you send it 200 pulses and the shaft will rotate 360 degrees. Send it 100, it will only move 180 degrees. If you want it to spin, just keep sending the pulses and it will keep spinning. If you want the motor to move to an exact point, then send it the number of pulses to get to that point. (this is a very gross simplification of a pretty complex system)
So how does this all play out?
The Dragonframe software on the laptop controls the scene. You use that to position the camera and work out the camera movements. It will then send these movements to the DMC-16 Dragonframe controller. This controller sends the step pulses to up to 16 motor drivers. The drivers take those pulses, and will power the coils within the motors to get them to behave as expected.
With this, you can get a very predicable outcome, and get repeatable moves. You can program the movements, and replay the routine over and over, and the motion will always be identical (as long as you take care in building the rig, don’t have anything binding up, etc).
So the next step is to get these all wired. I have a pair of 36v 16amp power supplies that I will use to power the drivers. I picked up an empty server chassis to house these in. I am hoping to get this wired up monday.
The Pan Tilt system is in!
I manged to get the Pan/Tilt/Roll hardware from ServoCity. It is the PT-2100 w/ roll attachment. It really is pretty badass. It can handle up to 40lb loads, far more than I will do, but I wanted to get something solid, and solid it is. The bearings are fantastic, the motion is smooth. The only issue is it might be a little bit big for what I need, which means I may have to slim it down a tiny bit. I am not worried about that though. Ill address that later if it becomes and actual problem.
The unit came with no electronics, no motors, which saved me 350. I was just going to replace the motors and had no use for the controller, so that worked out nice.
The 50:1 geared steppers arrived, of course, I cant play with any of this shit until I get the drivers and power source wired up monday.
I have some design considerations I am still mulling through. The big question is the Z axis. I am not quite sure how that will all go together just yet.
The Otto Frame
This is the biggest cause of concern for me. The design has already taken a couple directions. But I am fairly sure I am on the right track now. I will be building this out of 8020 aluminum extrusion.
The overall frame design should be good. I will be using some fully supported bearings with 1500mm ball screws. So this is basically going to be a giant CNC machine. The X axis is figured out. I just need to make a few final measurements. The Y axis, i have to chose between two layouts (not going to bore you with the details) and then the Z axis which raises the camera up and down… well… I’m sort of stumped. I will figure it out though.
I am Hoping to get all the frame materials ordered in the next few days. I want to order now, but any mistakes could prove to be costly and waste money. So better to check, measure, design, double-check, double-measure, confirm design. THEN order exactly the parts I need, and only the parts I need, all pre-cut so all I have to do is assemble.
Now, time to get to building.