I'm use a 60D, 5DIII, FS100, and have just started tuning a Scarlet on mine. The specs on the 5208 say that it handles up to 1500 grams. Right now it weighs 3200 grams with 5D3 flight ready.
i just setup a handheld gimble with 5208 for pan and it hold good now i am going to setup the pan on the gimble too!! i wil let you now how it went when i am finish
3 5208's with a 3.6:1 gear reduction, alexmos with 3rd axis add on. I don't have any pictures of the handheld portion and these are a few weeks old. I've since swapped the pan motor for a 5108.
When you use the gear reduction (with a drive belt), doesn't that negate the advantage of having a direct drive motor somewhat? Doesn't the drive belt introduce some unwanted play/looseness in the system? Andy.
I run both 3s and 4s depending on what camera is on there. I have several different pulley combinations I can use, and run 4s for heavier cameras.
The belts hold tension perfectly and don't have any slack. The biggest drawback to the servo belt drive was slop in the servo gear that was then multiplied by the gear ratio. The downsides to the belt drive are a slightly more complicated setup, additional weight (not very much), and needing to run higher pole motors than direct drive. Lower pole motors take longer to get tuned with the belt reduction because they can cause some slight cogging. It can be tuned out, but it's best to have higher pole motors. The pan axis is the only one where I saw any adverse effect from cogging, but it was also running a slightly higher reduction. I swapped out the 14 pole 5208 and put a 22 pole 5108, and the cogging went away.
Thanks for the clarification, Matt. I suspect folks will want to know how you made the parts for the belt reduction -- did you custom make them yourself? Andy.
I started mocking everything up originally with 1/4 MDF to get all of the spacings the way I wanted, and then transferred those templates to G10 to use while I waited for the parts from the machine shop. The motor mounts I had custom made from a buddy at a machine shop. They are just laser cut 1/8 inch aluminum. The bolt pattern for mounting to the boom is 32mm center to center and square for mounting in either orientation. I spaced the boom mounting holes and motor mounting holes 35mm apart which allows for just enough clearance of the motor from the boom while still being able to run wiring in between if necessary. The motor bolt patterns can vary, I can't remember exactly what the 5208 patter is, but iflight has cad drawings for the motor they sell. Originally I was going to have custom shafts made for the mxl pulleys, but I found that 3515 prop adapters were perfect with 5208, adn 5108 motors. The pulleys and belts are 1/4 inch mxl from mcmaster carr. The pulleys are 1/4 inch bore and the prop adapter are 6mm. I use thin aluminum a/c duct tape in one small strip to center the pulley on the prop adapter and the set screws lock them in place. The tape isn't really necessary, but I wanted to make sure they were centered. The pan axis motor mounting was a bit more challenging because of clearance issues between the star mounting plate and the top of the pulley, as well as belt alignment. I used 2 pieces of 1/8 inch G10 to drop the motor mount to the correct height. When I was changing everything over to brushless I decided to just rebuild the gimbal all together. I widened the camera tray, lowered the down tube, and added close to 20 metal boom clamps throughout. My alexmos with third axis expansion board, receiver and bluetooth module are all housed in a project case from spark fun and mounted under the roll axis. I offset the project box opposite of the the tilt motor to help get the roll balance closer.
Does anyone manage to tune the Alexmos 3 axis extension board? All 3 axis goes crazy when I plug it in. If I bypass the IMU from the board - roll and tilt is fine...
Can you snap a picture of how you have the boards mounted? Which 3rd axis expansion model? Make sure you have ferrite rings around each motor lead, and the sensor cable with at least 2 turns and as close to the board as possible. When you first hook up the 3rd axis, you will want to unhook all of the motors and perform an IMU 6 axis calibration with both boards powered. Since your roll and tilt are functioning properly, after the calibration only hook up the pan motor and make sure its spinning in the right direction then you can start to tune the power and PID
Same board I'm using. You'll need 6 rings if you run in that configuration. I removed the top board on the 3rd axis expansion and split the sda and scl from the sensor to clean up the wiring. Try to keep the power and motor wires as far from the imu sensor wires as possible.