I have been off this forum for awhile, and one of the key reasons is that I stopped lugging my gh2 around and started lugging my DIY multirotors around. Originally this was a venture to get some nice aerial shots before leaving Japan, but as with camera's, lenses and all the other equipment that is involved in the image capturing hobbies, it becomes a bit of an addiction.
The intent of this thread is to build a rolling user guide of what in my opinion makes a good reliable setup for consistently smooth predictable video shots and smooth consistently predictable flying while spending more time in the air and less time on the bench adjusting things, repairing things, and upgrading things. Those three things are largely related, but depending on what your after, your personal strengths, and endurance, mentally and physically, some things may be more important for you to focus on. This intro is a basic layout of what I find important, but I plan on building on it with questions, and others personal experience. I will do my best not to be overly wordy, and appreciate the same from others so that this can stay as streamlined and readable as possible for those just getting into DIY multirotor builds. It is not for everyone and many would be better off buying a ready to fly off the shelf unit, but for those willing to learn, I believe the DIY route will in the long run save you allot of money, and allot of frustration.
Advantages of DIY
There are more advantages, but yeah were keeping it short (I hope).
OK, so here are your basic needs when building a machine.
1) Frame - I recommend a hexacopter between 550mm and 700mm diameter for your first machine. A quadcopter will save you a bit of component money, and is usually more nimble in the air, but the redundancy of the hexacopter gives you a bit more breathing room should a motor or esc fail in the air. It is also more stable and less prone to sudden movements (when tuned). There are many options and price ranges. Early Tarot aluminum frames can be had for very cheap places like GLB. For about $100 you can get one of their Carbon frames. Early Tarot are arguably better than the newer ones and rather than buying a cool looking newer unknown companies frame which may be fine, but may not, it is a good idea to go with a known stable platform. Those frames also have allot of mounting space, so you won't find yourself jamming a mess of wires and components into the tightest spaces on earth (been there done that).
2) Flight controller. This is the brain (just gonna leave it there for now). I recommend a pixhawk, Eagletree Vector, or a Revolution (usually sold as CC3D revo). Current prices on Pixhawk clones on ebay are as low as $50 for a complete board with all the wiring, but you will need a separate GPS unit. I recommend a M8n Gps unit which can be had for about $20 on the same site. You can get them elsewhere for this price range, or pay allot more. A Revolution board is about $30 on ebay for the nano version, but getting the larger (still very small) "CC3D Revo" board is in my opinion a better option especially for a beginner. This board includes built in telemetry which you will need (lets you talk to the board with a tablet or phone). You will also need a GPS unit. Avoid the nano GPS as it is crap (TRUST ME). Get the same size M8N GPS unit, but be sure it is for the CC3D boards. If it works with one CC3D board, it will work for the rest. This can be had for about $20.
3) PDB (Power Distribution board) . This simply routes power from your battery to the components that need it (note pixhawk has a power unit, but it also needs to go to a PDB). Here you have many viable choices but you need to be sure it will not blow if your battery is too strong. Most likely you will have a 6s battery for aerial video (yes other cell counts can work, but 6s will give you more power and flight time), so be sure the PDB is 6s capable. For the pixhawk there is a pricey at $20 (most pdb are $5 or less) PDB that can handle 10s! it has a handy connector for the pixhawk pdb to plug into. Considering the money your saving with the guide I am making here, I would probably go with that pdb if I was going pixhawk. Even if you are running 6s or less, it is nice to have pdb capable of handling allot more juice especially since accidents do happen, and you'll be less likely to short something. Some other PDB's have built in Voltage sensors and OSD's which we can discus later.
4) ESC's (plural) These plug into the flight controller and get power directly from the PDB. Your flight controller is both sending them signals based on its build in gyroscope to keep the machine level, and from your input on your transmitter (dual joystick thingy). The ESC's in turn send these signals to your motors, as well as send them power from the PDB. FYI there are all in one esc's (usually only 4 to a unit for quad copters), if you are building a quadcopter for aerial work, avoid these. If one fails you have to replace the whole unit ie all four esc's. In general that is a $100 repair vs a $25 repair. I highly recommend Either Kiss 6s esc's, Afro 20amp HV (high voltage 6s ) esc's, or Favourite little bee 6s esc's. There are other good ones out there but allot of risky ones. I HIGHLY recommend flashing the Afro's to BLheli and the others which are running BLheli firmware to the latest version and will get into that later.
4) Motors (who knew). Yeah, well these spin your props. Every other motor will be spinning clockwise, and every other counter clockwise. Each flight controller has it's own pattern, so be sure to either find an imagine online to reference, or if you have a Revolution the GUI will kindly show you. FYI there are motors out there with built in ESC's. Avoid them. First off their specs are rarely impressive, secondly if an esc fails, you are out a motor and esc, if a motor fails you are out a motor and esc. Not to mention if you ever want to upgrade either unit you are upgrading both units, as in all esc's and all motors.
5) Propellers - I recommend buying 3x what you need in plastic and the necessary adapter to allow this, and 2x what you need in Carbon fiber for the day you feel confident that your not going to crash into a tree, or tip on landing and chip your blades. CF is tough, but it can break. There are no two ways about it plastic props are ridiculously cheap (or should be), but rarely provide the stability desired for AF, and CF are expensive. I recommend RCtimer signature series for CF props as they are less than pretty much anywhere else, and more often than not are very nicely balanced. For perfect props you almost always have to do some sanding, but that is a whole page and video to explain.. If you can afford it, but 4 or 5 sets of props, pick the best, and sell the rest or keep them for backup.
6) A prop balancer. Cause you need to know. There are many cheapies which I think are fine. I paid about $40 for a Dubro (think that's how it is spelled) that has high acclaims. I think the cheap ones are easier to use though.
7) Transmitter and receiver. The transmitter is what goes in your hands to control it, the receiver goes on the machine to send what your telling it with your hands to the flight controller. There are $3000 transmitters and $20 transmitters. Do your self a favor, get a Frsky Taranis Transmitter for between $200 and $250, and an X8R receiver for between $30 and $50. This transmitter and receiver both give the $3000 units a run for their money. I have never come close to using all the functionality, but there are many customizations for both flight controller and gimbal I have taken advantage of through the transmitter.
8 GIMBAL (WHAT'S THAT WORD AGAIN? MONORAIL...Er GIMBAL!!) This is where you absolutely want to listen to me unless you want to put a dslr on the machine in which case your talking an 800mm plus frame, or unless you want to spend months dialing in a device. GET A TINY2 Gimbal. This is the best no stress gimbal on this planet for the gopro size camera's. I do recommend eventually getting an alexmos and storm32 based gimbal too, but if you start with either unit, you are going to end up with allot of throw away footage, and likely a dead gimbal, and actually a very likely DOA gimbal. That being said my first TINY2 had issues I didn't realize were there.. and that is because even though my first unit was faulty (which is very rare with this gimbal) The majority of the footage was still very very impressive. My second unit which I still use is flawless. The only down side to this gimbal is it's limited proprietary Firmware. It is supposedly based on Alexmos, but almost all customizations are not available. HOWEVER. Because it is out of the box so good, and because you listened to be and got the FRSky Taranis and X8R receiver, you are going to be able to still customize some important things like panning/pitch speed, as well as center position, ie you can tilt the gimbal slightly down to avoid props in the frame.
9) OSD (On screen display). Eagle Tree Vector comes with this build in and it is the best OSD period. Both other units you will need to spend btween $10 and $30 for an OSD, this gives you vital info on voltage, gps signal, distance of machine from pilot, direction, and the list goes on
10) VTX (Video transmitter) It is what sends the signal from your cameras (plural) to you on your ground. Yes you can fly with just a gopro, but it is not recommended because first of all the way gimbals work the camera is not always pointing forward, and this can be very confusing when flying and result in a crash, also if the gimbal malfunctions either due to defect or user error you may be trying to negotiating your way home while staring up at the sky or down at the ground, bottom of the machine, etc.. So invest in a $20 - $40 FPV camera and a $5video switcher which will let you with a flip of a switch on your taranis switch between up to 3 cameras. Surveilzone.com is my recommendation for both.
OK, well I have allot on my plate these days, and can't add any more at the moment. I think I got all the major components. There are obviously wires, and some specific connectors needed sometimes to get things connected. Practicing soldering before you start will be your friend. 12awg, 16awg, and 22awg are good size wire guages to always have around. and you can practice with them. Heat wrap in similar guage is also a must. A heat gun is good idea too.
I will try to get back to this soon, and have a rebuild of my 680mm hex starting very soon, so can takes some pics as I go and answer questions.
I hope I have at least provided a framework to start with and maybe answer questions that you had bouncing around in your head.
I'm looking forward to seeing some pictures of your rebuild! I've been interested in DIY drone stuff for a little while now - both for flying a slightly bigger camera with nice(r) video quality than my Mavic (RX100 V for instance), but I've also been interested in building some very small drones for specific tasks (e.g. mini drones just big enough to haul a lume cube which I could use to light stuff).
In terms of the video transmitter, do you have any specific suggestions for one which supports an HDMI input?
Added small formatting.
Thank you @mee This is interesting, please continue this series and I'm looking forward to seeing pictures in the future.
Looking forward to this thread. Subbed!
Glad to see the interest here, I will try to post more this week, but please bare with me.
Eatstoomuchjam, I actually build more mini (250mm range) machines, than large machines and sell them locally, they are racers (some of the fastest) but I have been designing something based on the racing frames I use the most as well as my own original frame design both of which are intended to be small but powerful machines capable of carrying a gopro on a gimbal. Recent improvements in small motors and esc firmware has made this a much more realistic venture. A Lume Cube, or even several would be a cake walk for this type of machine. Though because of the torque nature of these racing machines there may be micro vibrations that look like a sorta flicker on your subject. With proper tuning I imagine you could eliminate this, but it may be painstaking. A more viable option may be custom mounting the light to a gimbal (Tiny2 still my recommendation) You could even custom mount a fpv camera next to the light to easily control where the beam is pointing. The gimbal (especially tiny2) should eliminate the vast majority of vibrations. Keeping it in a stable position is the other challenge, and that is where a good gps unit, good baro, and good open area with as many satelites in view as possible will be your friend. Pixhawk with an M8n on a good day is ridiculously locked in in my experience My knowledge is more real world than tech, and tech knowledge can improve a less than perfect lock.
As for HDMI transmission, I do believe I have seen one or two units, but to be clear, it is my understanding that you will not actually be able to transmit or receive a true HD signal at least not with what seems to be available to the RC community. Maybe a more serious broadcast intended unit can do this. I am only going based on my own research several months ago on this matter, and would love to be wrong, as even for fpv I crave a higher grade image.
Did you try DJi F450 and F550 kits ? They are usually enough for small gimbal + camera combo.
Also, bare 3DR solo has 720gm payload - and there is a cheap 2-axis gimbal for Sony NEX cameras. That can easily be used for a very light MDSLR, or for Sony X3000V (which is the best image in action cams ATM). You can use storm32 board from cheap 3-axis storm32 gimbal. The 3DR battery can used to power the gimbal and the tilt controls works. With a little soldering you can do a lot over here..
sorry for leaving this topic for so long. I recently moved and should have a nice work shop set up soon that will be more conducive to building and video/photo logging my projects. Till then...
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