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Photo drone Mk1

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by large_ghostman, Apr 15, 2018.

  1. large_ghostman

    large_ghostman Well-Known Member Most Helpful Member

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    Actually its a bit more than a photo drone, its payload is the new top of the range Nikon Camera and a huge lens. I dont have access to these for now, not sure when i will actually get to see them.

    But my mum has the nikon D810 and a 2.8f 200mm lens, slightly less weight than the real payload but good enough for some later tests. To start with the payloads will be dummies, even i am not stupid enough to stick that kind of money on a untested drone!!

    Mike posted about a 4 stroke petrol engine and i cant find the thread!!!

    For now I will be using methanol to start with and 2 stroke, mainly because of cost and most the hard work is the drone control and not power. The flight time is roughly 40-50 mins, so its doable on batteries, but for various reasons i want to go with a small engine and generator. Nothing at the moment is off the table, its likely to be 6 or 8 motors, for the drone. Because of the lens and stress and the camera to lens mount, the camera and lens are going to be fixed to the drone.

    This means the drone is going to have to be stable and accurate to position. If i can get a reasonable proof concept then i get the cash to take it further. The main issue people seemed concerned about is tethering the Nikon to a laptop while on a drone. The distance from the operator isnt that large so i dont see this as a problem at all.

    Much of the product stuff i mum shoots she does tethered, its not a big deal. Bluetooth is out because of range, but bluetooth to something else (maybe wifi) is easy enough. The prototype will use mainly small devboards, mostly sil labs because I have loads and any i need are only $30 with gold contacts etc! I will also be using there light sensors and UV index sensors, this is so the drone automatically makes sure its facing away from the sun etc.

    I wont be starting for two weeks but will update weekly after that.
     
  2. Pommie

    Pommie Well-Known Member Most Helpful Member

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    Photography is the one area where I'd stay away from internal combustion because you can't elliminate vibration. When you say tethered, do you mean an actual cable? I've wondered about powering static drones via a cable to the ground. If you used a 110v center earthed transformer then, it's safe and the cable shouldn't be too heavy. Or 48V DC at 20A should keep 15kg aloft.

    Mike.
     
  3. large_ghostman

    large_ghostman Well-Known Member Most Helpful Member

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    Hi Mike.
    No on the Nikon pro cameras you can tether wireless, the only version of this i am aware of though is bluetooth, or cable. Nikon has its own tether software, but adobe lightroom also has the drivers for Nikon. You can control every aspect of the camera via the software including mirror lock etc or switching over to 4k video. I thought about vibration, the lens has VR control for vibration. Its not great in normal circumstance (well not with me), but it works well with steady frequency vibration.

    There should be a way to get reasonable damping, or get the shot as good as you can then switch to battery to take the shot. Its something i would need to play with. We have some lenses with VR on (vibration reduction) but not the 200mm one, the 300mm one that would be used for the final thing does have VR. The other option is bursts of 4K video and take stills out or use stacking software. My part is two fold, my mum has done some local work for the archeological society and the bronze age and older mounds around here.

    There is a third year uni project, they are looking at using hi res images like you get from the D810 (although they have the newer better Nikon that hasnt been out long), from the little i know of the project they take X amount of pics of each square meter or whatever from above, they then mess with the RAW data file colour channels and stack them. I have seen 2 pictures they did from a cherry picker 30 feet up. It apparently makes identifying possible dig sites much better, not sure how the photography side works, but you see outlines using the stacking software that you cant normally see.

    Then this narrows down the areas where they do the ground scans. My mum is a pro photographer (well was, she mainly does product and wedding work now). So my parts are to get the drone done for this, she then thinks she can use the system for wildlife stuff which was her thing or rally work where its hard to follow from behind etc.

    The blue tooth from the camera could connect to pass through board, maybe even a simple arduino and use the wifi from that to connect and stream the pics and data to and from the laptop. The D810 isnt as fast as the D4 or the new D5 which is maybe the one they will use, the D5 takes 12fps and does bursts of 200 shots at 14 bit lossless RAW format. It isnt as hi res as the D810 but even that does around 9fps for about 100 shots per buffer at 14 bit (might be slightly off on the 810).

    So with good isolation and rapid bursts it should take a fair bit of vibration especially with the lens VR. I cant get near the D5 for at least 6 weeks, they are using it for testing the software stacking. But i could set the D810 up on a platform and vibrate it, see what the shots are like. If i use a couple of phone vibration motors and maybe a servo, it should give me an idea if its possible. If it was me i would use the 810 because of the quality is second to none. I just checked and the 810 in full frame mode is 5 fps....lower than i thought.

    At this point a few tests cost nothing, i could even put a small 2 stroke on the mount board and see what happens.

    Can you link the engine and motor you used again please, i cant find it. Also i got a nag about model railway track points, they use capacitor banks to fire multiple points in quick succession, i am wondering if the phase problem could be overcome using something similar. Each phase feeding a controlled bank, the motors taking the power from the banks, i cant remember what the train guys call the bank set up.

    The other thought goes back to the sil labs outrunner dev kit. I have two of these kits
    https://www.silabs.com/solutions/industrial-automation-and-power/motor-control
    the ones in the video. Whats interesting is the psu for the board is around 3A but 35V, running full wack the motors draw around 18A (measured). So small gear box and one of those small 3 phase microwave turntable motors, they kick out 240V at low RPM (measured). So maybe there is a way to use something like that to power the motors, take the 240V and drop it but beef up the current like the dev kit does.

    You seen the 8 motor quad set ups with 4 motors like a normal quad, then 4 more upside down directly under them? Those are supposed to offer the best stability and power, but would need alot of juice.

    Also how did you work out your lift capacity? I am told there is a formula for it but cant find it. The other ideas are around using wooden props shaped for low acceleration but high speed, something like a 11 X 6 or whatever it is.
    Because i have most of the stuff for testing (might need some new motors), it should be pretty cheap to build a small test version, it wont lift the weight needed but should give a decent idea if its workable and if things like shrouds and vectoring the motors help at all.

    For alot of reasons a ground cable wouldnt be an option for this, but its also something thats crossed my mind, especially POE added in.

    Welcome your thoughts, and like i said there is alot of things i ca do with stuff hanging around. If we get good results then i can at least present something and see if they want to put the money in for a decent 4 stroke etc. I cant lay out for something like that on the off chance, but then again a small version using what i got, and results from a vibration bed should be enough to take to them. Funny thing is, having seen some the pictures taken from the back of a motor bike going at 85mph, vibration isnt my main concern.

    Breaking this https://slrhut.co.uk/product/ID589C...YG9eu4vtPyk3aOioc1lLEyUAQfLJfarkaAtZVEALw_wcB

    and this

    https://slrhut.co.uk/product/ID2178...Zh3oALvinwo-LuU09jcCFZdVlZVE4aEQaAmr_EALw_wcB

    worries me a fair bit especially as it isnt ours lol

    edit, just noticed the D5 has wifi built in, still its alot of weight to get off the ground.
     
  4. dave miyares

    Dave New Member

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  5. Pommie

    Pommie Well-Known Member Most Helpful Member

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    The 4 stroke motor is the OS GF40 - fuel consumption chart. Linked to a Turnigy rotomax 50.
    The biggest problem by far is rectifying the 3 phase voltage without causing excessive heating of the motor. If you just use rectifier/capacitor then you only take current around the peak of the waves and cause massive overheating in the motor. You need power factor correction so the load looks like a resistive load.

    As for lift capability, I got my numbers upside down. It's approx 150W per kg or 6.6kg per kW - above I did 15kG per kW. Big difference.

    However a cable carrying 1kW would not be that heavy. Might be worth consideration.

    Mike.
     
  6. large_ghostman

    large_ghostman Well-Known Member Most Helpful Member

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    The problem with a cable would be the risk of getting it in shot, and distance or it leaving marks that are picked up. 6.6kg per KW is also a head ache!! No idea how i would sort power factor correction, thats something i will need to look really closely at. Thx for the model numbers, i couldnt find the post.
     
  7. large_ghostman

    large_ghostman Well-Known Member Most Helpful Member

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    Not exactly what i am looking for
    https://www.researchgate.net/post/H...e_generator_terminals_of_a_AC_DC-AC_converter

    The train module i was on about and cant remember, is the sort of thing i think you are on about with correction. The motor acting as a generator charges a bank via a circuit, normally the bank is 3-4 times the output voltage of the generator. Its then passed to a circuit that corrects the voltage and ups the A. Really bad explanation sorry. But before i delve too deep into this, i think its worth looking at how much i got to lift, i got a nasty feeling i wont get enough lift trying it this way.

    Once you start getting past a few kg the engine size and motor to generate start getting beyond sensible limits in size and weight, add to that the fuel needed and its all a bit silly. Before i tackle that i wont to look at the vibration issue. Oddly my mum thinks the vibration shouldnt be an issue if its a steady kind of vibration, its one of the easier tests to do so i will start there, if thats a dead duck then its game over anyway.

    I got emailed one of the final pics of 4 square meters from a test site, these where done from 40 feet up a crane basket. The before pics look like normal grass in a field, the processed pics look almost like an xray but 3 colours, they clearly show where earth was disturbed long long ago, fascinating research. Someone said to look at the helicopter camera gimbles and fix the loads to those.
     
  8. dave miyares

    Dave New Member

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  9. large_ghostman

    large_ghostman Well-Known Member Most Helpful Member

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    Pommie
    I found this, first of all its bigger than we have so far discussed, but in principle much of what the guy talks about is relevant (i think so anyway). I thought you might be interested, now he seems to have done alot of work on this, he ditched 4 stroke engines and went with 2 two stroke. He states he decided to forego fuel efficiency and gives his reasons, i admit its a long video but if you get a chance i would be interested in your take on it.

    2 stroke would suite me better because of what i have to hand, but that isnt the point. I am keeping an open mind, but posting this because its one of the few videos thats been well thought out. Not sue it changes my view, and certainly his rig is alot bigger than anything i have in mind.

    If you get a chance to view it i would welcome your comments and views on it.

     
  10. large_ghostman

    large_ghostman Well-Known Member Most Helpful Member

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    Actually i like his channel alot so i have subscribed, i have also maybe might of downloaded some in mp4, or i might not have done depending on how legal that this :D

    What i didnt realize was his is a 2KW system!! So maybe i am going to have to go big!
     
  11. Mickster

    Mickster Well-Known Member

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    I must have viewed this vid before at some point, because it began playing where i'd previously left it, at around 25 mins.
    Guess I need to work on my attention span a bit more, to reduce the ratio of unfinished/finished projects....ooh look, a bird!
     
  12. large_ghostman

    large_ghostman Well-Known Member Most Helpful Member

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    Mick you sick puppy!

    Did you not read my post on a drone V bird recently!!! With mates like you............:D

    https://www.electro-tech-online.com/threads/death-of-a-awsome-drone.153793/
     
  13. Mickster

    Mickster Well-Known Member

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    Yes I saw it, but wasn't thinking of that when I posted the above.
    Before the internet came along, (you likely have a small gauge for this, due to your age - aside from parental restrictions during your early years) there were books, and books, and books, plus some courses. There weren't the same distractions with the books etc, as there are currently with YT vids and websites. Watching something mostly-interesting, with a glittery side menu specifically catered for your own interests and listing so much enticing content, can be somewhat distracting. To the point of when a particular video no longer holds 100% of your focus, something potentially more interesting is just simply a click away.
    I think information overload can be a bit of a problem for some of us, who never had so much available at our fingertips when growing up. Many of the pipe dreams we had at some point are now much easier to rekindle, because a lot of the missing pieces are now out there on the 'net.
    Past projects we had on the back burner are now easier to complete, but the new tech with all of the bells and whistles can condense our previous 6" x 4" PCB onto a single die and increase the IO, memory and tack on WiFi connectivity as well. New, shiny stuff, just out there for the taking and so much more to add to that past project...


    The "ooh look, a bird!" part was included in the vows when my wife and I got married, in the Public Gardens in Boston.
    We decided not to use the traditional vows and wrote our own very personal ones. Making my wife laugh is a goal I like to achieve at least once a day.
    The particular line where it was used went something like this - "I promise not to get distracted when you are telling me off, or telling a long-winded stor....ooh look, a bird!"
    Timing could not have been better, as there were numerous small birds flying around, as well as ducks flapping around in the water.
    The photographer and officiant had to take a few moments to compose themselves.

    TL-DR? - maybe I have a bit of ADHD.
     

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