I’ve just completed the repair of my now formerly broken Arris CM3000 Pro 3-axis gimbal.  The CM3000 Pro is a 32 bit 3-axis gimbal for GoPro cameras.

There were a few broken pieces which were not that easy to replace due to the wiring for the pitch motor and the pitch sensor.  There’s some carbon fiber framing in the shape of an “L” which goes from the pitch motor to the roll motor.  Both sides of that framing were broken.  I ordered CM3000 replacement parts from Hobby-Wing, but the whole L piece came as an assembly, glued together.  Otherwise I would have just replaced the sides which were broken.

The broken gimbal:

Broken Gimbal

I had to unsolder the four tiny connections to the sensor located under the camera:

Then had to unsolder the three connections on the main board for the pitch sensor in order to unthread the wires from the old broken L arm.

Also, all the plastic screws which held the protective box for the SimpleBGC gimbal controller were broken, so had to replace those.

Repair complete.  Still need to test out the gimbal and make sure it works.

Then it is on to rebuilding the Alien H4 680 quadcopter.

I’ve been semi-happily flying this new Alien H4 680mm quadcopter build.  I say semi-happily because I’ve been in jello hell, trying to get rid of the video vibrations and wobbles.  That, and the new landing gear I installed included one unit which was defective.

I spent a week (not 24/7 but you get the concept) balancing props and motors (motor balancing video coming soon) and reduced the overall vibrations quite a bit.  I was out flying over a construction area, where there’s some open dirt and a few unoccupied homes being built.  I was testing to see if I’d gotten rid of the GoPro jello effect.

That’s what I made a mistake that I was not aware of until it was too late.  Suddenly the bird started to nosedive.

It crashed in some very soggy sod behind one of the new houses.  One arm and prop was so impaled, it took almost all my strength to get the arm out of the ground.  There was quite a bit of damage, though mostly small and inexpensive parts totaling up to about $120.00.  The cost could have been far worse.  The hours it will take to get it repaired, after waiting for parts from China, is the real pain.

The Mistake

Fortunately the MiniX flight controller keeps a log.  That way I could look at it to see if any information could help me diagnose the cause of the crash.  The log showed me some good news and bad news.  The good news was that the crash was not due to any kind of equipment failure.  The bad news was that it was user error.

I unknowingly had flipped into manual mode, thinking I had flipped to GPS mode.  At 177 feet the props stopped spinning enough to keep the bird airborne.  Seven pounds of carbon fiber, metal, and plastic hits the ground in about two seconds from that distance.  No time to react.

I couldn’t believe the log and that I’d been such an idiot flipping to manual.  A look at the switch on the remote confirmed MY error.

Solution

I never fly manual and I don’t intend to with this, or any of my copters.  I don’t do trick flying.  My ships are for aerial photos and video.  I plan to either disable the manual switch (not the best idea in case of emergency when GPS fails or somesuch thing), or set my remote to delay 5-10 seconds and produce an audible “manual mode will activate in five seconds” type of thing.

Below are a few stills from the crash video.

Battery is UNDER the bird.  This is not supposed to happen…

Battery ejected on impact. Velcro straps shaved off with razor precision. Gimbal vibration ball on left flying through the air.  Long rectangular donut-shaped item is one of the gimbal control board box’s side panels, about .5 inches wide and 2 inches long.  It must be right in front of the GoPro lens.

Top gimbal mount plate flying through the air…

Motor arm sure looks far away…

Fat Shark FPV camera flying through the air…

FPV camera left of tree points back. Too bad it was unplugged and not recording the view looking back toward the GoPro..

FPV cam still in air, motor wires from rear motor arm severed…

Battery still in air…

Quadcopter impaled in ground. Rear motor arm would soon break off.

Assessing the damage…

Broken Gimbal

Carbon Fiber props did some sod cutting

Core components and wiring survived. GPS tower toast.

I’ve gone through TOO many hours of troubleshooting my retractable landing gear for this Alien quadcopter.  I’ve been hand catching the bird on landing since the 4th arm’s gear has decided not to work.  Below are some social networking comments, put together regarding the gear.

Well this is messed up. My #4 gear will NOT work when the props are running. I’ve had to hand catch the thing every time I put the gear up. Put it in my shop with props off and just spun up the motors in manual mode and sure as hell, #4 won’t go. I’ve even got a 10A BEC for them.

This is irritating. After moving the retracts around, changing the servo plug, and taking it apart and messing with it for 2-3 hours (not worth the cost), the thing IS defective.

https://www.youtube.com/watch?v=rKPxAzZsVZM

Got an RMA with hobby king but it is chinese new year, so they’ll get to it in about 6 months. Thinking if just buying another one or two somewhere just to get the damn thing flying.

I decided while waiting that I’d extend all the gear and disconnect control. That way the bird will be balanced and I can fly while waiting for a new retract (and I’ll get one or two extras). Oddly, while flying one or two moved slightly then went back to straight down. This is with servo signal wire disconnected, but power still connected. Strange eh?

So after intermittent functionality I took the retract apart and put it back together a few times.  Still no-go.

I’ll be ordering replacements but it is Chinese new year, so everything is on hold.