I finally gathered all of the remaining parts to complete my slow motion ladder dolly. Although the dolly worked fine, I wanted to add a few features like:
- Limit Switches: This will ensure that that dolly stops when it gets to the end of the track.
- Forward/Backwards switch: An easy on/off switch that also changes directions
- DC Motor Speed Controller - Potentiometer: Allows me to slow the motor down even further
Again, most of these ideas came from the DIYPhotography.net post here. The biggest difference is that they made their own collapsible track, and I'm using an extension ladder as mine. They also use a timing belt, where mine just wraps fishing line around the axle. Here are some updated images of my dolly:
I mounted the battery by using the bungie cord off a couple of ball bungies to hold the battery down. I'm probably going to add a bracket to the back to ensure it doesn't slide off if I'm doing a steep incline. I also replaced the T-Nuts on the sides of the dolly from the ones that just had the teeth, to the ones that had screw holes. This should ensure that no matter how many cameras are mounted to the top, the wheels will not buckle.
I used an aluminum hobby box which was purchased at Radio Scrap, and tried my best to solder and heat shrink all of the connections.
I've also added a bunch of 3/8" and 1/4" screws sticking out of the desk in various locations. This will allow me to have up to 4 mount locations for my Ball Head holding a dSLR, and 6 possible locations for the GoPro or Canon G11 on a standard mount. I have a coupling nut on the rig in case I want to use my Manfrotto flexible neck mount to get some "looking straight down" shots.
I put a limit switch on both sides, to it will stop when it gets to the end of the track going in both directions
The guts of the Potentiometer are also inside the Aluminum housing, and allows the rotation to be extremely slow. I'm planning on putting the dolly on the ladder track this weekend to see how slow I can make it move.