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Schottingham posted:So I may have misunderstood something about servo control signals--I had thought it was an analog voltage, just based on my multimeter, but I've read a couple of places that it's actually PWM, is that right? Is there a standard mapping between pulse width and servo position? Would it suffice just to throw an RC filter on that line to turn it into an analog voltage? Even so, the voltage is really low (a couple hundred millivolts) and is below the dropout voltage of the op amp I had planned to use; I may have to buy some rail-to-rail op amps to make the gun trigger work. Servos are just DC motors with negative feedback to make the motor go to a certain position as fast as possible with critical damping (as little slow-down or overshoot as possible). Basically the motor feeds positional and velocity feedback into its input, and you don't want to mess with that if you don't know what you're doing. The term PWM doesn't apply here. edit: PWM can be used with a filter to make a DAC, so that might have been what the guy was talking about quote:Edit: Also some old HAM dude was telling me that RF can damage your eyes at a certain power level, even if it's not ionizing radiation. Is this guy loving crazy or should I actually be careful? I was under the impression that unless the radiation is ionizing, the only danger is from heat. RF with enough power is literally a microwave oven. Your eyes tend to cook first. If you're using power levels that don't require a license, you really don't have anything to worry about.
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May 13, 2011 05:13
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Schottingham posted:I didn't mean the feedback internal to the servo, I'm pretty familiar with how that works. I mean the position command sent from the receiver. This page for example describes a pulse width of 1500us representing neutral, while 600us is -90º and 2400us is +90. Is something like that fairly standard? Oh, sorry. So no, a smoothing filter won't work because it takes a digital signal, not an analog one, yes that's common, and I don't understand quite how you're doing this, from reading your post history. Are you making an antenna to send a separate signal to your own plane-mounted gun to actuate a servo that physically pulls a nerf gun's trigger?
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May 13, 2011 06:42
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Trabisnikof posted:900Mhz is only used by old analog cell phones now, so I'd give it a try. I've deployed a 900mhz radio system for something else in a city before and was able to handle any cell tower based interference. This isn't right, but they do use a pretty narrow band, so the chances of interference are pretty low.
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Dec 15, 2011 01:42
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I climb cell towers for a living, and I've started taking a GoPro up towers. Is there a good flying camera platform I can supplement that footage with? Something that can fly up to an altitude of 300 feet or so, but I guess I could get away with only 150 for some of the shorter towers. 720p video is a must, and I'm also not really into assembly or learning how to fly well or anything like that. I just want to take some cool video. What are my options?
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Dec 14, 2012 17:07
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The parrot looks pretty cool. I'll look at it some more when I get near a laptop. Any other similar suggestions are appreciated, too. The towers I climb are exclusively 850/1900/2100 bands, so interference shouldn't be an issue.
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Dec 15, 2012 01:18
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He said in the video that GPS kicked in around 18km (60,000 feet), but he was too far downwind to make it back.
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Apr 13, 2013 00:24
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Hey guys did you hear that GPS only works up to 18km?
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Apr 13, 2013 02:40
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There are a bunch of articles going through the hurdles around now, I think Wired has a couple. Basically right now, for commercial drones, they'd need constant LoS, which is obviously pretty impractical for a delivery service (they'd need to drive a chaser car all the way to the destination anyway). The FAA is trying to figure out some legislation, but it's looking like that'll come about closer to 2020 than Amazon's timeframe.
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Dec 3, 2013 20:49
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Mm, yes, let's just get rid of all those complicated and inefficient self-driving cars and replace them with simple, easy-peasy self-piloting flying machines that totally have a 90% efficiency while in the air
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Dec 6, 2013 19:57
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Vitamin J posted:Well there are no commercially available self-driving cars, only prototypes that costs hundreds of thousands or millions of dollars and are not at all adapted to delivering goods and cannot be operated without a human passenger. This is a pretty funny post. I doubt that slapping a LIDAR unit on a Prius costs hundreds of thousands of dollars. Yes, the program costed millions, I'm sure, but guess what? The technology is here. And from all reports, true self-driving cars are already able to navigate the (far less) chaotic and unpredictable world of roads better and more reliably than humans. The "open 3d space" stops being very open when you start putting tens of thousands of drones through designated airways, add in another axis of movement where poo poo can go horrible wrong, and when it does, it's a whole lot more catastrophic than a car crash. Also motor efficiency doesn't mean a lot when you're trying to fight gravity, something land-vehicles don't have to do.
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Dec 6, 2013 22:18
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ease posted:You're an idiot, and here's why. Straight lines will always be more efficient and safer. RTK gps will allow for these drones to fly w/ in 1cm xy and 2cm z. It's already possible now. Machine vision will allow it to detect any kind of interference and play around it. And where not talking 32 degrees of vision, we are talking complete spherical machine vision. Spider poo poo. Not to mention that soon, it will be required that everything in the air have some sort of ADS transmitter. Hell, I'd go as far as to say in 15 years we'll loving tag geese with whatever the next generation of ADS is. So you're saying that the magic of RTK GPS can overcome wind gusts, machine vision that requires seeing everything in complete sphere is easier to accomplish than machine vision that only needs to be 360 degrees on a flat plane, and avoiding unexpected objects in the air (evasive maneuvers) is just as simple as avoiding stray dogs on the ground (stopping). Also doing all of this while overcoming gravity in a straight line is cheaper than doing this with a 10-block detour to main roads while only overcoming rolling resistance. Yes, I'm the idiot here. Maybe if they can airdrop packages with a plane-style drone, but I dunno, that makes it pretty hard to sign for packages. Helicopters aren't exactly known for their fuel economy.
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Dec 7, 2013 03:33
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ease posted:I win. Hahahaha Gettin' mad about Amazon delivery methods in here. You throw in a fact about GPS being good to a few cm, and then act like that is a totally accurate measure and can be relied on in gusty conditions. I only joined in on this conversation because of that one post that had a whole bunch of faulty comparisons, but that's cool, I guess, if you want to keep spewing points that don't really work in the real world. You can win. (I guess to fully spell out that rebuttal above, to get any kind of money-earning volume in deliveries, you'd need to be spitting out a shitton of drones one after another, and if you need to give them huge margins of safety space that's not really possible. Automated cars, on the other hand, can draft each other, with only inches of space between them because they actually have brakes (drones don't have air brakes))
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Dec 7, 2013 04:52
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mashed_penguin posted:
That's actually a lot better than I thought. I don't think anyone was saying that it wasn't possible, just that it's not as viable as land-based drones.
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Dec 8, 2013 01:56
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Vitamin J posted:
 Are you really this dense? The cars are fully capable of autonomous navigation, they just need a dude in the driver's seat for liability reasons. This is a temporary caveat. By the same token, fully autonomous commercial UAVs are illegal in the US. This is also a temporary situation until the regulations can be updated. Your unwillingness to concede that point shows such a ridiculous bias that I can understand why D&D hates you.
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Dec 9, 2013 20:11
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mashed_penguin posted:The only thing my drone has killed is my dignity. https://www.youtube.com/watch?v=q7kwhtslOYQ&t=79s GET OUT OF MY CITY AHHHHH
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Dec 12, 2013 07:43
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Are people 3D printing custom FPV planes? Or jets would be cooler. Here's what I know: 3D modelling software is readily available and readily used by the masses. Something that's been printed with a very low infill is ridiculously light for its size. There are open-source alternatives to practically everything now. Certain kinds of jet engines are pretty easy to homebrew. Here's what I don't know: How easily engines (probably scramjets?) can be adapted to something that is relatively small and subsonic. If there are specifically open-source projects involving aerodynamics simulation. If 3D-printed materials are strong/accurately printed/smooth enough to be feasibly used. Fuel concerns. I dunno, I don't see any reason why it can't be done, but as I said, I don't know all of the facts.
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Dec 14, 2013 01:09
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How much would one of those gimbals alone cost? One of the problems I have with mountain biking or snowboarding is that a GoPro is fisheyed, which is good for catching everything, but terrible for catching anything important and display it large enough to see anything. It would be pretty neat to write some software that can pick out important objects (bikers, boarders, skiiers) and pan/tilt to follow them, without a fisheye lens. That could be cool. Edit: looks like that line of cameras has pretty crappy resolution (I think) does anyone know of a good 720p or higher system that would work for less than maybe $100? ante fucked around with this message at 05:41 on Feb 10, 2014 |
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Feb 10, 2014 05:36
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I wouldn't want to use a GoPro because of the wide-angle lens. A much more typical focal length would be better. For snowsports, image processing would be cake, just follow everything not-white. Biking would be much trickier, but I guess it would be doable to mount the gimbal to the handlebars of the follow-bike, and put a ping-pong ball on the tail of the lead bike.
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Feb 10, 2014 05:56
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Someone at my local hackspace just finished iterating his laser-cut quad frame. If you have access to a laser cutter (if you're in a major metro area, it's likely that facilities exist), give it a shot https://github.com/vhs/multicopters/tree/master/untitled-quad He also needs a name.    
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Mar 9, 2014 06:39
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