Better Build than a DJI Phantom?

[seaninsc]

Hi all,

A little while ago, I build my first fpv mini quad. After learning to fly, I found that I loved strapping a GoPro on and filming with my qav250 more than flying around and doing acrobatics. Now I am interested in building a mid-sized quad or hex capable of flying a gimbal with a GoPro or other small camera to satisfy my new found videography addiction.

This brings me to my question: Can I build anything better than a DJI Phantom for cheaper? If so, what kinds of frames/electronics would you recommend? I know quite a bit about miniquads but next to nothing about larger quads or hexes. Would a 500mm frame with 800kv or so motors work? What kind of FC? I would like to have GPS and maybe waypoint, but if those options are to expensive than a simple, stable FC recomendation would be great. Also, how do gimbals work? Do they plug into the FC's or do they have their own controllers? Should I make one or buy one?

Thanks,
Sean

 

[Snarls]

For the price, you probably can not build anything better than the DJI Phantom. You can however probably build something close in capability. The engineers at DJI optimize the product to do the most using the least. Each part is design with a purpose. In contrast, with DIY builds you end up with extraneous parts and parts that are not optimized to work with each other.

Basics of a build:
A lot of DIY AP rigs use 400-500mm frames with 800-1000kv motors and 9"-11" props. This is a good size for GoPro gimbal hauling machines. To narrow down to a specific power system you might want to do some calculations on ecalc to see what combos have the best efficiency for your payload. For a FC you can run something easy with basic GPS functions like a DJI Naza or Tarot ZYX-M. Or you can get more technical and get an APM/Pixhawk based flight controller which will give you waypoints and can even use optical flow sensors if you buy them. There are lesser known brands that have functions in between.

For a gimbal I would recommend buying one unless you want to spend a lot of time tinkering with a DIY build. How exactly gimbals work is a whole other post, but brushless gimbals require a dedicated controller. They need to be very well balanced and extensively tuned, much like a multirotor, hence why it can be difficult to make one. I am currently working on a 3D printed 3 axis gimbal design, but I could get to filming faster if I just bought one.

Next you can add an FPV system of your choice to give you a view of what you're filming. Then add a big honkin battery and you got an AP machine... Actually you will likely have to spend a good deal of time dialing in the PIDs and GPS settings before you get really good performance. Then you'll have a really sweet, stable camera rig. But it will still be lacking behind the DJI Phantom due to lack of FPV user interface and the new sensing and following tech DJI just released in the P4. Saying that, if you are serious about AP and have true pilot skill you probably wont need sensing and following aids.

The DIY route can be a slow road to the goal of AP work, but it is not impossible at all to get there.

Hope this helps for basics. If you want more in depth info on anything like frame choices, how gimbals actually work, or anything let me know.

 

[finnen]

Good advice right there

But, tbh, it barely makes sense to build yourself.

If you want a hd downlink, that alone will cost almost as much as a p3 advanced.

If you don't want a hd downlink, you might be interested in the p3 standard, which is 500$ now! Really hard to beat that.

There can be other reasons to build diy, but economically it doesn't make much sense.

 

[evilmerlin]

Unless you are planning on carrying something bigger than a GoPro. Just get the Phantom. It's really hard to beat for the price.

 

[Cyberdactyl]

I would agree with snarls that, for the price, it would be hard to match the functionality and elegance of a Phantom, plus the almost Apple-ish look of both the copter and the transmitter.

But if you are willing to trade that "image" for a DYI look, I would offer that you could build a quad with similar functionality for roughly the same price. Plus an added benefit of being much more rugged, possibly sacrificing an additional ~150g. Phantoms are made of slightly durable plastic. You could build with something like 3mm G10 throughout and have a literal unbreakable frame.

 

[evilmerlin]

Really? You could build something with a 4K camera, 3-axis gimbal and a HD video link for the same price? Not being sarcastic or anything because I would really like to know how.

 

[Cyberdactyl]

Really? You could build something with a 4K camera, 3-axis gimbal and a HD video link for the same price? Not being sarcastic or anything because I would really like to know how.

What's the exact budget? However, I will admit building something similar to the new Phantom 4 would be a challenge, since I'm not familiar with the new features such as optical and sonar obstacle avoidance and Tapfly. Of course then the budget would be $1,400.

However if the budget is $900, I believe it can be done to approximately match a Ph3. I would agree that the effort would probably not be worthwhile unless you merely wanted to learn how everything works in detail and wanted an extra rugged frame.

 

[jipp]

to me it seems it would be a good idea building something on the side even if you do get a DJI product.. so you have a better understanding what is going on the hood.. because problems do happen in the field.. and if its something simple.. you could fix it and get your bird in the air to finish the job..

i bought a sonar for my AP build. ( collecting parts for it.. no clue when ill have all the parts. since im i no hurry i have got good deals on what i have so far.. i only paid 10.00 for the retractable landing gear, so yeah sometimes its good not to be in a rush ) im just going for a 680 hex tarrot pro. of course my AP machine will not have all the nifty apps and such which i think is a huge bonus for the phantom..

but in the end i still think a pro AP guy is gonna build him self a machine to do the jobs he wants.. or maybe im wrong.

chris.