Introduction: Time Lapse Rover for EMotimo TB3
Time lapse footage is becoming very popular, and adding motion to the clips adds interest to the final results. Using an eMotimo TB3 as the controller, I was originally limited to a 6 foot rail system for 3-axis motion. I wanted something stable for the camera, but also be able to traverse a number of different terrains, not just something smooth. This DIY Rover build allows the camera to travel hundreds of feet using the TB3 as a "the brains." A majority of parts for the Rover were purchased from ServoCity using Actobotics parts. Think of Actobotics as the grown-up version of the Erector set. I've also called this a "Hyperlapse" rover, as it allows me to capture time lapse photography sequences over long distances. This rover is built to travel very slow, and will not impress anyone with it's speed, but the stepper motor that I use has plenty of torque and precision for amazing sequences.
I try to share a ton of images of the rover, but don't necessarily go into detail on how I put some of the parts together. I'm hoping that the images speak for themselves, and that I've put enough notes for you to figure out how one part attaches to the next. Basically, the way the rover works is the TB3 sends a signal to the camera to take a picture, and then the rover moves a very small distance. Then, repeat. You can set the interval, ramping, how far the rover travels, and how many images to capture in the TB3 setup. In addition to the rover moving laterally, the TB3 can pan and tilt the camera during the move.
Step 1: Parts \ Supplies
Here is an inventory of what I used to build the rover. The parts here are for the version 2 of the rover. I made a design change when ServoCity released a new beveled gear, thus giving the ability to add 2 wheel drive. The original design only powered one of the Rover wheels, and this one powers the entire back axle. This rover uses the eMotimo TB3 as the controller. You could use other solutions, but this instructable assumes that you have a TB3 which allows for 3-axis motion. Here is the parts list:
- 1 x 10" 1/4" Precision D-Shafting
- 2 x 4" 1/4" Precision D-Shafting
- 8 x 1/4" Ball Bearing Quad Pillow Block***
- 3 x 1/4" Plastic Spacers
- 2 x 1/4" Aluminum Set Screw Collars
- 1.5" Aluminum Channel
- 2 x 9" Aluminum Channel
- 1 x 15" Aluminum Channel
- Flat Single Channel Bracket
- 2 x 1/4" 32P Bevel Gears
- 2 x Quad Hub Mount E
- 1 x Quad Hub Mount C
- 1/4" Flanged Ball Bearings
- 1 x NEMA 17 Stepper Motor Mounts
- 4 x Hex Hub Wheel Adaptors
- 2 x 1/4" - 20 Round Screw Plate
- 1 x 3/8"-16 Round Screw Plate
- 2 x 1/8" Hub Spacer
- 4 x 1/4" 6-32 Socket Head Machine Screw
*** My build uses different parts because these were not available in the original build, and I used a combination of Dual Ball Bearing Hubs and Quad Hub Mount C's for the connection near the wheels. For the front axle, I had to use additional flanged bearings and Quad Hub Mount D. I would recommend using these for a simplified parts list.
- 1/4" x 1" Screw
- 3/8" x 1.5 Hex Screw
- Velcro for Battery
Step 2: Design Changes - Version 2
The original design used a stepper motor to drive one wheel on the back axle. It used a combination of hub gears with the motor mounted on some offset aluminum channel. Although this seemed to work fine, I made the decision to power both rear wheels once a new option came on the market. Bevel Gears gave me the option to now move the stepper motor underneath the main aluminum strut and turn the entire back axle. It distributes the weight evenly on the rover as well, as stepper motors are fairly heavy. The only change that I would make to the design is the use of the NEMA 17 motor mount. Since the stepper motors I've purchased from both eMotimo and Stepper online have planetary gearboxes, having more of a flush mount would eliminate the need to order specialty metric screws and spacers. Unfortunately, the planetary motor mount from ServoCity does not fit the screw hole pattern on the eMotimo or Stepperonline Stepper motors.
*** For another project, I was able to use a drill to expand the hole pattern on the ServoCity planetary gear mount and force it to work. I'm not sure if the hole patterns are for imperial versus metric, but until they come up with a different part that fits, I recommend using the NEMA 17 mount.
Step 3: Stepper Motor Wiring
When I purchased the eMotimo TB3 as my 3-axis time lapse solution, they only had a few options for stepper motors. A 27:1 geared stepper motor that is slow, but maybe too slow for the rover, and a 14:1 all around motor, and a 5:1 for fast moves but no torque. These are excellent motors as the have the TB3 connector built right into the motor, and all you need is the jumper cable. I have a few other DIY eMotimo accessories, so I wanted more motor options. For this project, I went with a 19:1 geared stepper motor from Stepper Online. This gave me a bit more speed than I have for my time lapse rail, and seemed to have plenty of power to push the Rover around no problem with the camera weight. Unfortunately, these motors need the correct molex connector to integrate into the TB3. You can buy the Molex jumper directly from eMotimo, or get them on Sparkfun.
You will need some soldering skills to wire the molex connector to the motor wiring. I used some mesh sheathing and heat shrink to clean up my wiring, but it isn't necessary.
- Black Motor –> Black jumper
- Green Motor –> Red jumper
- Blue Motor –> Orange jumper
- Red Motor –> Yellow jumper
Step 4: Wheels, Tires, Bearings
The front channel support has 2 independent axles so that the tires can rotate freely, whereas the back axle is one long shaft so both tires move together. When I purchased the parts for the rover, the 1/4" pillow block hubs with built in bearings were not available, so improvised with other parts and used the combination of dual ball bearing hub A with a Quad Hub mount. The pillow block with bearing is a more elegant solution, and I would use that if I had to do it over again. Therefore, the parts list in this thread uses the pillow block hubs with bearings.
I also recommend using some type of lock tight glue on the wheels screws, as I found myself having to tighten them more than I expected.
Step 5: Rover Chassis
From Legos, to Lincoln logs, to Erector sets, Actobotics parts are awesome to work with and allow for extreme creativity and innovation when working on projects. Creating the chassis for the rover was fairly simple, and used Aluminum channel as the support structure. The Actobotics channel for the front axle is connected to with a simple combination of a Quad Hub Mount E, a 1/4" screw, and a 1/4" Round screw plate. There is 1/8" hub spacer between the screw plate and the hub mount. This allows the front axle to be rotated so that the rover can drive in either a straight line or an arc depending on how much the axle is turned. The back axle and channel are connected using the same parts, but instead of using a 1/4" screw to allow rotation, it's mounted perpendicular with multiple screws and no ability to rotate the axle.
Step 6: Rover Protection
I wanted to ensure that the rover was protected in transit, so I ordered a pelican case. The nice thing about this case is the pick and pull foam that allowed me to create a nice place to nestle the rover inside a protected hard case. The eMotimo TB3, batteries, cables, and wii controller fit nicely into one convenient travel package.
Step 7: The Results
The above videos are all time lapse sequences that use the DIY Rover to capture a motion sequence over an extended distances. To really see the rover travel a large distance, you need to allocate a few hours. You want short moves between pictures so the time lapse is smooth. I'm still experimenting with the settings. I hope to have more time this summer to use and play with the rover. Thank you for reading my build!