I want to build a mini AP still photo multirotor

[Stet Hindes]

With two working multirotors up and going, I am under the impression that they are too big for what I want to do which is shoot high quality still photos in an urban environment. My concern is basically that the larger machines have a bigger impact should something go south. I am also becoming increasingly suspicious about FC failures after my Naza decided one day to do a rollover, only to right itself just before impact. Mine currently run on Wookong and Naza V1. The Wookong is on an SPS X4 and carries a Canon S110. The other is a TBS Disco which has a fixed Gopro mount with no gymbal and is really just for FPV and experimentation.

My idea is to build a small FPV racer style MR to carry a Gopro for taking still shots. The only gimbal I need is simple unstabilized tilt. I would use the Gopro for the FPV camera. I am looking at the scale of the Blackout offerings. I like to use first quality components so would likely buy KDE or Tmotor motors and ESCs. I would buy a cheap gopro gymbal and minimize/modify it to only the tilt function, rotating about the CG inside the front of the frame.

I am not flying FPV, I will be flying by sight and use the FPV only for camera line-up. I am not flying further than 30 meters. I do plan to use GPS position hold. I do have issues of wind at times. My expectation is to get up, get the shots and get down in less than 3 minutes. Oh, and I plan to fly over unforgiving salt water.

So if you have any suggestions I would love to hear them considering the following.


4 rotor or 6? This is my biggest question right now. Is 6 easier for the FC and more stable? If 6 and one motor stops, can I still fly it home to land safely? I have never been clear on the 6 rotor loss of motor issue.

Switch to the APM system or use the Naza V1 (I see no benefit to go to V2, right?) The wookong seems too big for these platforms. I've been reading a lot of good stuff on the 3DR offerings.

Pixhawk or APM 2.6? I think I like the APM better since it is smaller and I would use a JR receiver with multiple satellites. I am not a coder, so there would be an effort to switch, but if more reliable I'd like to try it. I am not really clear as to what the Pixhawk has that is not on the APM 2.6, other than the plug for a JR satellite.

2S, 3S or 4S? What motor KV to go with your recommendation? I'm trending to 3S.

SimonK ESC's?

2 or three bladed props?

15A ESCs should be plenty, should I go less? What about Blackout's offerings? KDE's smallest is 20A. My X4 with 800 KV motors, 4S, and 11 inch props hauling 6.5 pounds AUW only draws 7 amps per motor in hover. Who makes the best low amp ESCs?

Hero 4 or 3? Hero 4 Black worth the extra $100 if only used for stills? Any issue with the video out for FPV if I shoot one still frame every second? I want the best still images possible and do not mind paying for the better unit. I have the Tarot video cable but could get something else if better.

Hero battery or leave it off (preferred for weight) and use a BEC to power the camera (I do not really trust the power output on the downlink Tx, don't know if it is switching or not)?

Assuming the shutter speed on the Hero is fast enough, it should not matter if the small MR is dancing around a bit in the wind.

Thanks

 

[TahoeTim]

Over salt water, i would build a cheap platform with a cheap and simple board like the Naze32 or kk board. Put PID tuning on a dial channel in your radio so you can tune in flight if needed.

Since you are interested in stills, can't you take video and then post process the footage in your pc?

 

[Bartman]

Oh, and I plan to fly over unforgiving salt water

one word, cheap. make it cheap and build them three at a time.

that would be my strategy, especially if your performance requirements for the camera are going to be so low. you can go really cheap and get what you're looking for with the bonus that if you dump it into Davey Jones' locker you won't miss it much.

IMHO.

 

[Stet Hindes]

Those are good ideas. Any thoughts on the OpenPilot board vs the Naze32? As far as grabbing stills from the video, those would be lower quality than I am looking for

 

[Bartman]

do either of those boards have GPS options? if not, buy yourself used APM 2.5+ systems from the classifieds and you'll get everything you could ever want, cheap.

 

[SleepyC]

I’m just starting to use the Naze32 board and for $25 I’m impressed. From what I am reading you CAN add a GPS and such, but it still won;t be awesome for AV. AP above saltwater and it could be cool.

 

[TahoeTim]

I'm thinking you won't need Gps hold for stills. That's why I suggested the Naze32.

 

[Bartman]

Most of what I did was photography and I have to say that the GPS came in handy when I needed to put my photographer's hat on and just concentrate on framing the photo. Once you're close it's nice to be able to just nudge the heli to a new spot, center the subject and then look at it critically without worrying about the heli drifting into something nearby.

 

[fmkit]

I'm using Naze32 only and can't think of any other controller that will let me do framing so precisely, even Inspire-1 don't come close

 

[Stet Hindes]

I like the position lock of GPS because I do not feel comfortable taking my eye off the MR to look down at my screen unless I know it's locked. The OpenPilot has GPS but only as telemetry, not a GPS hold. So the choices are now between APS, Pixhawk and Naza V2 (unless I pull the controller off my Disco). Now I have heard that the Naza does not play well with the small airframes, though I have seen some that built/use them. I will not be racing the MR, for that I would definately go with the Naze32 or OpenPilot. Anybody care to comment on Naza V2 on the Blackout hex airframe with KISS ESC's? I like the airframe but am a bit concerned that the FC area of the frame is not vib isolated from the dirty section (was trying to see if I could add that feature with an extra top plate betwen, but more weight. Though I would use first class damping tape between the IMU and the frame. Also, I have seen some add rubber washers between motors and frame, does that really do anything? Of course I would take the time to balance the props. Though I would like to go 4S for the power, I think I will go 3S in order to have the same 12V available for the downlink etc without having to use another regulator.

 

[Stet Hindes]

Peter that framing looks really good, am I correct to assume that you are using goggles or a large screen for your navigating?

 

[TahoeTim]

That's an expensive frame to fly over salt water. I will mention again the Hovership frame. It has an isolation layer but it can be assembled with or without the isolation layer.

 

[Stet Hindes]

Where I fly, the water is at most 10 feet deep, so the copter can be retrieved easily. I have a buoy to throw to the impact zone if needed. But I do not plan to fly over the water unless I am 99% confident in the reliability and stability of the system. So many hours will be spent burning it in and testing different flight profiles first.

 

[Stet Hindes]

What's the verdict on the Eagletree Vector FC? I note it has loiter and RTF functions. I'm reading mixed reviews on RCGroups.

 

[matwelli]

Just started using an old apm from 2011 used it today for aerial photography. Loiter was awesome. Enabled me to briefly take my eyes off it, shift position and then Yaw it around while staying in the same spot.

Did you see my minimal quad copter in the general discussion area ? I am about to re-do it. Uses 8 inch props but overlaps them for compactness and is sub 900 grams.
the 8 inch prop / motor combo is a lot more efficient than the mini quads.
materials were a 20 mm wide aluminium bar and a 400 mm long piece of pine

No matter what frame you go with mount the fc and receiver in a small waterproof container - will help it float