Bebop 2 focus problem, like everyone else!

tourmax · Jun 11, 2019

So it’s day 2 with the new bebop 2.

I’ve had a couple “crashes”, but all pretty mild and no higher than 6 feet. Usually get a little too close and clip something hard enough for the software to kill the engines.

Today I started paying more attention to the video.

Yecch!

Grainy, blurry, etc. Definitely not what I would expect from a 1080p sensor. I’ve got a couple Contour HD 1080p sports cams and the quality difference between those and the bebop are night and day. A car can go by at highway speed and I can read the license plate on it with the contour, i can barely make out my dog in my backyard on the bebop at 20 feet alt..

So, it either got “bumped” somehow or it was crap to start with.

So I open up the lenses. That epoxy is rock hard and I end up (essentially) sawing it off. Hard to belive a bump knocked it out of focus, my money is on that it was crap focused when assmbled.

Once apart, a good air dust and lens cleaning is in order.

How to get that lens back in is a different story. I’ve seen tape, teflon and all manner or glues in various videos. I tried the tape and it was just miserable and nearly impossible to focus. Even if I could get it focused, it would shift as soon as I took my hand of it or it would slowly drift out of focus as the tape/glue shifted around under torque/pressure.

Tried to find a nut (plastic) that would fit the threads on the barrel but no joy.

Then I noticed and old cb antenna cap lying on my bench. I snip a piece off and it’s just right to slip over the threaded portion of the lens barrel. It’s a good tight push fit down the sensor housing.

Once it’s all together, I find that the lens barrel is good and solid, but I can screw it in and out enough to focus. The cb cap is a harder type of silicone/rubber and apparently it is hard enough to grab the sensor housing and refuse to spin, but just pliable enough for the lens barrel threads to imprint on it and allow me to adjust the focus.

Tomorrow, I’ll take it out in the backyard and see how it works. If it’s good, I’ll put a dab of hot glue to keep it at the focus point. But should it come out of focus again, it will be a simple matter to peel off the glue and readjust.

Now, lets have a look at the sensor and see if they skipped the heat paste or not....

Iandico · Jun 12, 2019

Hi
Not had any problems with bebop 2 camera at all and find quality ok but does need good conditions and air temperature but in general a very very good trouble free drone to be honest.
Hope you get to enjoy same. Ian

tourmax · Jun 12, 2019

Well, test flight in the backyard this morning.

Video is much, much better! Still doesn't seem to be up to the quality of my Contour 1080 HD cams, but it's much closer than it was.

There is a "fuzzy" spot to the RH side of the image, which I account to the front lens installation at the factory. Rather than take it apart (like I've seen in other threads and videos) I'm just going to rotate the lens so the "fuzzy" spot is pointing up at the sky. I won't notice it up there as I'm usually looking at the images below the horizon.

While I had it all apart, I inspected the blades. A couple had small "dings" in the leading edges and the tip path plane was totally frigged on each rotor. Two rotors were easy as they had a hole in the center of each rotor, the other two were a bit more difficult to mount on something to do the static balance as there is no center hole.

Luckily, they were only dings and not missing chunks, so I used a chop stick (any piece of wood doweling would also work fine) and smoothed the leading edges back out. Then I adjusted the tip path plane of each rotor and finished with a static balance on each rotor.

Adjusting the tip path on an articulated rotor is fairly easy, you just add or subtract blade weights and adjust pitch links. All this together gives you a smooth rotor.

But the bebop rotors are rigid, being made of what appears to be a vinyl like material. Adjusting the tip path consisted of gently bending the blades on each rotor to get as close as possible to a level tip path plane. It sounds easy, but you have to be very careful when bending the blades to not change the camber or angle of attack on each blade. It's not difficult, but you certainly have to pay close attention to how you are changing each blade as you bend/manipulate it.

Then a good cleaning to get smudges, branch scrapes and grass stains off the body and rotors. A soft cloth and some water did most of the work, while a quick pass with a Mr Clean magic eraser took the hard marks off. Make sure you wipe down thoroughly with a moist towel (just clean water) if you use the Magic eraser. The eraser has a bleaching agent in it that could (eventually) mess up the plastic if not wiped down afterwards. The Bebop looked factory fresh once I was done.

When I put it back together for the test flight, it was immediately apparent the bebop was much smoother and more stable with the blade work done. Much less vibration overall and the rotors were even quieter as they buzzed though the air. Position hold was better and it did much better with any wind. Response to control input was much better, with the video flight mode now responding much quicker. I was even able to fly it (mostly) the way I wanted without having to go to "sport" mode. I do still have the yaw rate turned up in the video mode though.

Next up I think will be a polarized lens cover. Both to protect the Bebop lens and to cut down on some of the sunlight "washout" the camera seems to experience. You can notice the degradation of video detail when the sun is on it or reflecting off something. I've been putting off buying a 3d printer, but I just might have to bite the bullet now....

I also still have to do the heat transfer paste installation on the camera sensor to body mounting.

Overall, it's coming along nicely. It might not ever be up to something like a DJI Mavic 2 for video quality and features, but it will work just fine for my uses.