To start, I want to announce that my Spectrum will be here tomorrow. I haven't used my canon cameras in a while so I had to break them out this weekend and make sure they still worked! haha
By last Friday I basically had all of the parts I needed for the rail so I put it all together and sat in my computer chair staring at it since I don't have my spectrum yet. After a bit I realized I could use my time to rewire and fix one of the stepper motors I had setup for a chronos controller that had its wires ripped out in a panic for me to find my keys in my backseat last year. I'm pretty horrible at soldering so I got a new soldering Iron, an extra set of hands and a Multimeter to match up the right wires with the right motor coils and only took me a few dozen websites and youtube videos to finally understand what to do. Well kinda.... Anyways, once I rewired the stepper for the chronos controller I realized that I had a spare Molex jumper wire and I could actually make a cable to control my rail with the chronos controller.
I should probably explain that right now I only have my rail setup with the worm gear motor setup. The worm gear setup uses a different motor than the belt drive motor setup. The belt drive motor has an internal planetary gear that you can get in different ratios depending on the speed you'd like it to move at it's fastest, or slowest. The worm gear setup is more complex but offers no backlash, saves power by being able to power down the motor between moves and the non geared motor is smaller and lighter.
So yea, once I got the chronos controller cable setup for the worm geared motor I was finally able to move the cart along on the rail, which was when I found out that there was a big problem with the way the worm gear was set up. There was a lot of play in the shaft that holds the pulley that turns the belt, even with the pulleys. The pulley was actually rubbing against the screws and making metal shaving dust. I asked Doug what was wrong with it and he suggested using a 1/4" nylon spacer in the shaft and cutting it down to whatever size it would take to make it a snug fit for the pulley and shaft. Once I got that sucker in there it was smooth sailing. I was able to get the cart to go straight vertical on the rail with no issues at all.
Riding the wave of excitement from getting to finally see the rail in action I decided to have a pretty crazy Friday night and spend the next 4 hours calibrating my Chronos controller to work better with my rail. My controller was wigging out and becoming unfunctional when I put it in continuous mode, which is the mode I would be able to set keyframes on the cart to keep it from colliding with the end. After a brief talk with Chris (creator of Project Chronos) He told me to take out the motor driver and use small screwdriver and turn the potentiometer 1/4 turn at a time until the controller no longer has issue. Sure enough that worked like a charm. After a bit of playing around with keyframes I realized that it is just easier to just tell the controller to move 59 inches instead of having the cart go back and forth setting keyframes. For this to happen I needed to find the amount of steps per centimeter the motor is able to move the cart, this requires some relatively simple math but it's easy to get it wrong luckily Chris is all about DIY timelapse systems and provides a wealth of information on his website, including calculators to easily establish the steps per CM a motor gives. Then I counted the amount of full rotations of the worm gear it took to move the cart one inch (which was 10) and Chris's calculator gave me a Steps per CM of 787(rounded to 790). With this calibration plus the maximum length the cart can travel on the rail without colliding with the ends I am able to move precisely and repetitively across the rail. Being able to setup a shot on the fly and tell it a total distance and trust that it will hit it's mark is awesome to me.
Anyways, enough of the good, lets talk some bad. Going into this project i knew there would be a risk of issues and I could possibly be just throwing away money. When the parts showed up and the thermo inserts fit, I was ecstatic. You see, Doug designed this rail system to be printed on a Ultimaker printer and the tolerances in his design we catered to work with the shrinkage factors of his printer. Shapeways uses a different type of printer and even a different method so there was always a good chance things might not work out. For starters, the rails I am using were a bit loose in the end caps, they fit but if I tried to transport the rail, they would slide or at least rotate a bit while clamped down. To fix this, I used a single layer of electrical tape on the ends of the rails and now they fit snug and secure. Then on the static belt mount I was completely unable to slide the belt in. Simple enough fix, a bit of elbow grease and sand paper and it fits great. The biggest and hardest issue was definitely the fact that the wheels of the cart are not tight on the cart, between both sides there was about 2-3mm of play. This wasn't a huge deal to me at first because I was in my house and it was moving horizontal but as soon as I did a few vertical moves I realized it was a big problem. I talked with Doug about maybe redesigning the cart top to have the wheels come in a tad more but I really didn't want to spend more money let alone time waiting on a new cart top. Drilling new holes wouldn't work and I knew there was no way I could find bearings that were only 2MM wider. Doug suggested putting thin nylon spacers in to offset the wheels but I had a hard enough time getting ahold of the ones I already had in there. Then i thought, why not heat up the thermo inserts and angle them in a tiny bit, causing the bearings to move inwards towards the rail and filling the gap. If I go too much, It might ruin the wheel mount so I barley angled it and tested it and it was name near perfect. Once I had both bearings angled in on one side the cart was holding onto those rails like never before!
I apologize for the lengthy post but I wanted to go over everything that progressed with my build over the past few days and I really wanted to boast about calibrating my chronos controller and make a note that there are issues coming up but luckily so far there have been relatively quick fixes.
Saturday I decided I wanted to put some blue loctite on some of the cart bolts to stop them from vibrating loose on transport and since I would be taking it apart anyways, I setup a few cameras and made a little timelapse of the teardown and assembly of my system. Unfortunately the next day I realized that I never sprayed my 3d printed parts with a clear coat to waterproof them and spent the majority of Sunday doing that and it will be curing for the next couple of days, just in time for my Emotimo spectrum to arrive on Tuesday.
If you made it this far, Bravo and thank you.