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4s = about 14-16 volts, right? And you're probably going to be drawing <100mA to run the camera, right? Just buy a 7812 linear regulator for like 75 cents and solder it in before your ESC/UBEC.
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Mar 27, 2014 04:54
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I've avoided them in the past on planes due to the heat, but I should give one a try mounted out on the arm with a little heat sink and see how that goes now that I am on a quad. The power draw has to be more like 500 since this is also powering a 500mW transmitter and I am getting three flight batteries for every charge of the 450mah 3s.
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Mar 27, 2014 05:08
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Most of those 7800 series are rated for about an amp or two of continuous current as long as they're attached to some sort of heat sink (usually soldering to the ground plane of the board works fine, actually) so I imagine your idea is solid. It's certainly the cheapest way to go. You can probably also find a premade 12v buck converter somewhere, and it would have pretty high efficiency if it's only dropping that small amount of voltage, but it would probably be larger than a linear regulator + heat sink and certainly would be more expensive.
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Mar 27, 2014 05:12
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tehk posted:What's the general opinion on getting 12v on 4s for fpv gear? I have some lawmate grey channel 1.2 gear that I am getting tons of performance with but I am not satisfied with how I am handling power on my discovery. http://www.dpcav.com/xcart/Adjustable-Voltage-Regulator-1-35V-Step-Down.html With 12v gear you can generally run it down around 10.5v for the same performance and less energy wasted to heat. This reg is fully adjustable. Another option which is easy is a regular 5-6v BEC with a 5-12v step up like this: http://www.rangevideo.com/en/voltage-regulators/144-12v-300ma-step-up-power-supply.html
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Mar 27, 2014 05:18
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Got a question about ESCs, its not specifically for an aerial vehicle, but this is the only RC thread I found so maybe someone reading this could help? Basically I want the most powerful/cheapest ESC I can get. I don't care about BEC I found this thing: http://hobbyking.com/hobbyking/store/__18016__HobbyKing_Red_Brick_200A_ESC_Opto_.html There is another even cheaper(29.99) 200A one on hobbyking but its on backorder. Is this price/performance too good to be ture? What are the odds it will be capable of running anywhere close to its rated current? Do cheap ESCs like this tend to burn out often? Any other recommended devices in similar price and current rating that would be considered reliable? I'm not afraid to get my hands dirty and modify things if necessary, could add better heatsink or possibly replace mosfets for higher rated ones if needed. I would also like to have the option to reprogram the firmware. I noticed there are a couple of open source ESC firmware projects on the web, so something known to be compatible with one of those would be great. This will run on 12V and used to run a car alternator as a high powered motor.
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Mar 28, 2014 02:18
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Sagebrush posted:Most of those 7800 series are rated for about an amp or two of continuous current as long as they're attached to some sort of heat sink (usually soldering to the ground plane of the board works fine, actually) so I imagine your idea is solid. It's certainly the cheapest way to go. Should I add capacitors on the input and output to avoid any oscillation issues? I have it working without but I feel like I should know better than to put something so simple and cheap in the air. If it comes to adding a filter as well I might just stick with the extra battery. Too many points of failure at this point and I trust this little lipo
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Mar 28, 2014 03:19
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peepsalot posted:Got a question about ESCs, its not specifically for an aerial vehicle, but this is the only RC thread I found so maybe someone reading this could help? I decided to look into this, and this might be helpful: http://www.etotheipiplusone.net/?p=3096 It looks like the red brick ESCs are made of stacked up FET boards with dubious thermal transfer. While it's unclear if 200A refers to peak or continuous current, I'd put my money on peak. One all of the internal FETs start to heat up, it won't be able to get enough heat out of there quick enough. It would work better in something flying, where there might be active airflow, but only to an extent. Replacing heatsinks and/or FETs won't really do much good---the whole design is flawed. Shoving a ton of FETs into a small volume is a great way to deliver tons of current for a short time, but not continuously. Regarding reliability: The designs on a lot of these ESCs aren't uniformly terrible in general (aside from these huge dumb 200A things). Build quality and QA suffer in order to make it that cheap, but that will usually result in out of box (or soon after) failures. Looking at a bunch of RC car ESCs, much bigger heatsinks (with fans) seem to be common. In fact, the one he links looks pretty cool: http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=24754&aff=15144 As for programing, the SimonK Firmware is pretty standard. It says it supports "Hobby King Red Brick 200A (RB200A, black board)". Not sure if this refers to a specific version of the Red Brick or what. Hope you like AVR assembly! https://github.com/sim-/tgy
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Mar 28, 2014 03:21
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Are you actually using a 200a rated alternator? If so I am not sure how long the ESC would last. All the 250a+ ESCs I see seem to retail for $200+ so you would probably be better off sourcing a golf cart speed controller. I am very interested in this, cool stuff.
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Mar 28, 2014 03:32
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FPV talk: Fat Shark is releasing their new HD stuff in April (or so they say), wonder what price it'll be at, and whether their existing stuff will see a sale.
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Mar 28, 2014 06:33
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Slanderer posted:I decided to look into this, and this might be helpful: tehk posted:Are you actually using a 200a rated alternator? If so I am not sure how long the ESC would last. All the 250a+ ESCs I see seem to retail for $200+ so you would probably be better off sourcing a golf cart speed controller. I am very interested in this, cool stuff.
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Mar 28, 2014 06:44
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Mister Sinewave posted:FPV talk: Fat Shark is releasing their new HD stuff in April (or so they say), wonder what price it'll be at, and whether their existing stuff will see a sale. Dominator HD is $549 Dominator 2 is $375 The dominator 2s are pretty much the same as dominators but with a built in dvr. The dominator hd's use 800x600 modules and have a 45deg fov compared to 35 for the dominator 2s. I don't think I'm going to be rushing to upgrade my dominators. The wider fov would be nice though.
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Mar 28, 2014 06:57
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tehk posted:Should I add capacitors on the input and output to avoid any oscillation issues? I have it working without but I feel like I should know better than to put something so simple and cheap in the air. If it comes to adding a filter as well I might just stick with the extra battery. Too many points of failure at this point and I trust this little lipo Depends. I wouldn't worry about HF noise as the battery itself does a good job of stabilizing that sort of thing. I suppose you could get induced HF on the output lines but that's a lot less common with brushless motors than with the old brushed cans and their spark gaps. It's *possible* that your motor and battery are sized in a way that if you suddenly slammed the throttle from 0 to 100% the battery voltage would temporarily droop (talking about a matter of milliseconds), and if it goes below the linear regulator's minimum dropout voltage you could have problems. A decently sized electrolytic capacitor on the output would help with any ripples like that. However, you don't really know if that's even something you need to worry about unless you hook it up and watch it on an oscilloscope. Do you have access to one?
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Mar 28, 2014 08:01
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peepsalot posted:Got a question about ESCs, its not specifically for an aerial vehicle, but this is the only RC thread I found so maybe someone reading this could help? Theres a land RC thread in AI but I dont think they will be much help either since you're not doing much with RCs at all.
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Mar 28, 2014 08:07
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tehk posted:Should I add capacitors on the input and output to avoid any oscillation issues? I have it working without but I feel like I should know better than to put something so simple and cheap in the air. If it comes to adding a filter as well I might just stick with the extra battery. Too many points of failure at this point and I trust this little lipo Sagebrush posted:Depends. I wouldn't worry about HF noise as the battery itself does a good job of stabilizing that sort of thing. I suppose you could get induced HF on the output lines but that's a lot less common with brushless motors than with the old brushed cans and their spark gaps. It's *possible* that your motor and battery are sized in a way that if you suddenly slammed the throttle from 0 to 100% the battery voltage would temporarily droop (talking about a matter of milliseconds), and if it goes below the linear regulator's minimum dropout voltage you could have problems. A decently sized electrolytic capacitor on the output would help with any ripples like that. However, you don't really know if that's even something you need to worry about unless you hook it up and watch it on an oscilloscope. Do you have access to one? Whoops, I missed this post yesterday. You definitely want to add caps. Even if it isn't oscillating right now, there are all sort of transient conditions that are probably causing it to malfunction. The 78xx design needs those caps to function properly.
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Mar 28, 2014 16:13
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I've been using my Turnigy 9x (upgraded with that EL backlight + programmer board) with the default modules for a couple years now, but I'm thinking it's well past time that I consider swapping in a new module so that I can use smaller (and lighter) receivers for mini quads. Anyone want to recommend a transmitter module and some receivers?
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Mar 28, 2014 20:58
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Depends on how small (or how far) you want to go. I'm using FrSky DJT with D4R-II receivers. I also have the smartieparts programmer board with the telemetry piggyback board. DJT:  D4R-ii:  These days I usually get my FrSky stuff from a dealer based in Novato, CA: https://www.alofthobbies.com If you want ridiculously small receivers with stuff like 3-axis gyro built in, you should look into the OrangeRX DSM-X module for JR radios because they have a bunch of DSM2 compatible micro receivers.
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Mar 29, 2014 00:39
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CrazyLittle posted:Depends on how small (or how far) you want to go. I'm using FrSky DJT with D4R-II receivers. I also have the smartieparts programmer board with the telemetry piggyback board. I use this exact combination on both my 450 quad and a micro quad and the FRSKY D4R-ii is a godsend - especially if the board supports cppm or similar. One cable for everything makes it so much tidier.
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Mar 29, 2014 06:03
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Slanderer posted:Whoops, I missed this post yesterday. You definitely want to add caps. Even if it isn't oscillating right now, there are all sort of transient conditions that are probably causing it to malfunction. The 78xx design needs those caps to function properly. Yeah I added a 22uf on the input size and a .47 on the output side. I also added a coil and another capacitor to filter out the battery noise. If this doesn't work well I will have to look into a OSD that will do this for me. My quad is getting awfully crowded. I mounted it on the top of my discoveries arm under a prop tip so hopefully that will do plenty to keep it cool. I will do a living room hover test I guess while it is raining if I can herd my cats into a bedroom to avoid them trying to tackle it(it is my fault they love trying to catch the nanoqx). Anyone know if the Orange UHF system does PPM and how much of a hack is it to make the JR module into a standard back rail mounted system for non expansion style transmitters? I need to get rid of servo cable clutter on this quad to make sand removal a little easier. It collects dirt like a vacuum
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Mar 30, 2014 02:47
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I ordered all the bits for my qav250 mini quad. I'm really looking forward to it. I predict crashing into many trees while trying to recreate the ROTJ speederbike chase with it. Now for the wait and neverending track n trace...
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Mar 30, 2014 18:19
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Whats a better choice for getting started with quadcopters? Buy something like the V222 from banggood or to build something from parts from hobbyking? (starting with an SK450 frame)I should add that I can solder.
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Apr 1, 2014 01:57
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Jumpingmanjim posted:Whats a better choice for getting started with quadcopters? Buy something like the V222 from banggood or to build something from parts from hobbyking? (starting with an SK450 frame)I should add that I can solder. I just got this based on a recommendation from CrazyLittle http://www.hobbyking.com/hobbyking/...dy_to_Fly_.html I couldn't be happier with my purchase.
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Apr 1, 2014 02:24
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front wing flexing posted:I just got this based on a recommendation from CrazyLittle http://www.hobbyking.com/hobbyking/...dy_to_Fly_.html Seconding this. It also has enough oomph with the included bigger blades to life my gratuitously overweight FPV setup on its maiden flight.
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Apr 1, 2014 02:58
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Just a note on that sk450 frame - I already broke the motor mounting ring on one of the arms. Definitely get <any other frame design> to have around instead of trying to fix that frame as-is. The arms are just poor design.
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Apr 1, 2014 04:37
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Whats a good choice for a frame?
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Apr 1, 2014 04:49
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Jumpingmanjim posted:Whats a good choice for a frame? I bought this one just in case I crashed while learning to fly http://www.hobbyking.com/hobbyking/store/__49725__Q450_V3_Glass_Fiber_Quadcopter_Frame_450mm_Integrated_PCB_Version.html Haven't had any problems at all with the stock one though.
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Apr 1, 2014 05:27
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I hate not knowing a reason for a failure. It makes putting parts back into the air scary. I did a awesome 5km out and back trip on my discovery from my house only to crash when hovering above my garage. I don't carry a gopro so I don't have any footage to analyze. From the goggles all I remember was being 30 foot up and then a sudden flip to the right(I think). Lost video seconds after. All my props were broken except for the prop on the one arm that snapped(left front). Zip ties on the left ESCs were broken off and found around the immediate crash site. Bullets on the left front were disconnected, left back ripped from the bullet. ESCs work and replacing the arm and props got me hovering. Motors seem fine. I am betting on a bullet connector being jarred preflight and vibrating out, or a prop failure which a strike with my garage makes hard to disprove. The only casualties were my crushed vtx, antenna, and my camera/mount which is still missing. I suspect it might be in the pool 15 feet away. Just wish I knew what I hosed up so I could avoid it before I order replacement video gear. Typically does a non spinning motor strike first and does it usually survive with little prop damage? Flight controllers need OS style logging.. tehk fucked around with this message at 04:09 on Apr 2, 2014 |
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Apr 2, 2014 04:04
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tehk posted:Typically does a non spinning motor strike first and does it usually survive with little prop damage? Nope. Motor stop usually just defines which axis the copter spins on as it falls out of the sky.
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Apr 2, 2014 04:31
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CrazyLittle posted:Nope. Motor stop usually just defines which axis the copter spins on as it falls out of the sky. Yeah on a quad you are usually going to end up with a diagonal spin. When I lost a prop in flight my quad was spinning out of control so quickly I didn't have time to do anything except cut the throttle. The prop that came off was fine 
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Apr 2, 2014 17:56
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mashed_penguin posted:Yeah on a quad you are usually going to end up with a diagonal spin. When I lost a prop in flight my quad was spinning out of control so quickly I didn't have time to do anything except cut the throttle. Cutting throttle / disarming's the best thing you can do, really. It turns out my last crash was because I was cutting the lawn (yes really really stupid, I know), and after a rough landing some grass wrapped around one of the motors. That hard-stop under power was enough to short out a few windings on one of the motor's poles, and as the short got worse it caused the motor timing to stall mid-air.
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Apr 2, 2014 18:32
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Getting pretty good with SK450. Haven't had any major crashes (plenty of close calls though). I have a little trouble when the forward part of the craft is coming towards me and sometimes a I land it a little hard and then to avoid a hard landing a goose the throttle but that's smoothing out. I'm still entry level and I was wondering if anybody had any entry level FPV recommendations for newbies. I don't need to buy the best of the best quite yet. Thanks.
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Apr 5, 2014 21:26
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Entry level you still have some choices. You have two video paths and two frequency paths. Either you can go ground station or goggles. Ground station setups can range from a 60 dollar car DVD player to a pelican cased diversity setup with amplification and tracking costing $500+. Goggles range from 250 to 700. With Fatshark offering a RTF transmitter included setup for like 270 which is pretty dang good. If you are the hacking type you could pick up Cinemizer Plus setups used for $150+ and stick those in goggles like I did but you wont have the included battery and vrx Frequency wise at the entry level there are very cheap 5.8 and 1.3 options however the frequencies have some major differences. 1.3 will have further range, obstacle penetration, and require large antennas(the size of a softball in the air). 5.8 has tiny tiny antennas(the size of a lolipop) and better video quality. Unfortunately it does not handle obstacles or range very well. Roughly a 100mW at 1.3 will perform better than a 700mW 5.8 setup. Because of the small size of 5.8 setups they can be mounted inside the goggles. If you are flying a quad like the SK you will be fine with the Predator V2 RTF which is basically a bolt on and go goggles solution. If you want to do 1.3 you are better off learning how to make antennas(IBCrazy's build threads) and getting a cheap 300mw+ hobbyking vrx and vtx for roughly $100. Then you have to figure out your monitor. Edit : decide on frequency and display type so I can help more tehk fucked around with this message at 06:15 on Apr 6, 2014 |
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Apr 6, 2014 06:09
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As far as frequency choice goes I really see no reason to not always use UHF for control with openlrsng working as well as it does and the gear being as cheap as it is ($35 for the tx & $20 per rx). This opens up 2.4ghz for video which is a great balance between penetration and antenna size. Lawmate 2.5 500mw tx's are $35 and are tiny. A basic RX is also around $35. You can get goggle modules to do a goggles only ground station or you can do the bigger ground station setup as well.
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Apr 6, 2014 07:20
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Honestly, whatever is easiest. I'm not looking for crazy distance, I live in an urban area so the only places I fly are small parks and such. Really I'm just looking for a balance of cost and simplicity. I was going to a screen as a opposed to goggles. Appreciate the help guys.
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Apr 6, 2014 17:38
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front wing flexing posted:Honestly, whatever is easiest. I'm not looking for crazy distance, I live in an urban area so the only places I fly are small parks and such. Really I'm just looking for a balance of cost and simplicity. I was going to a screen as a opposed to goggles. I started with an 8" screen and got goggles fairly recently. Goggles are a completely different experience so much more immersive. If you aren only going to be flying in small parks I would get 5.8 for video. The cleanest setup would be fatshark dominators with a 5.8 built in module. Then you just have a small cp antenna on the goggles and thats it.
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Apr 6, 2014 21:41
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mashed_penguin posted:I started with an 8" screen and got goggles fairly recently. Goggles are a completely different experience so much more immersive. If you aren only going to be flying in small parks I would get 5.8 for video. The cleanest setup would be fatshark dominators with a 5.8 built in module. Then you just have a small cp antenna on the goggles and thats it. Hmmm, goggles do sound interesting. Are these kits that are ready to go or do you have to piece it all together?
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Apr 6, 2014 21:48
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With HK overseas shipping, how long is normal for delivery times? I'm assuming 2+ weeks, but I'd like to get a vague idea so I know when to expect my package / when to call up my local post office and pick it up directly from them rather than trying to coordinate times I'm at home to sign for the package. (The last notification on the tracker is a March 28th notification that it was acknowledged in Malaysia)
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Apr 7, 2014 00:11
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Arcturas posted:With HK overseas shipping, how long is normal for delivery times? I'm assuming 2+ weeks, but I'd like to get a vague idea so I know when to expect my package / when to call up my local post office and pick it up directly from them rather than trying to coordinate times I'm at home to sign for the package. I've gotten things in two weeks to two months.
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Apr 7, 2014 00:36
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front wing flexing posted:Hmmm, goggles do sound interesting. Are these kits that are ready to go or do you have to piece it all together? The attitude v2 from fatshark is a good starter package. http://fatshark.com/product/1759.html You can get "nicer" stuff by buying a bunch of bits separately. If you want a one stop shop though thats the way to go.
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Apr 7, 2014 02:14
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mashed_penguin posted:As far as frequency choice goes I really see no reason to not always use UHF for control with openlrsng working as well as it does and the gear being as cheap as it is ($35 for the tx & $20 per rx). This opens up 2.4ghz for video which is a great balance between penetration and antenna size. Lawmate 2.5 500mw tx's are $35 and are tiny. A basic RX is also around $35. Anyone tried the Hawkeye openlrsng stuff? I am thinking about picking up the non module based one, but fpvlab keeps mentioning grounding issues and weird buzzing with their module versions so I am kind apprehensive. I need to move to a module based controller but I cant seem to unload my DX7s for anything worthwhile. tehk fucked around with this message at 01:45 on Apr 8, 2014 |
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Apr 8, 2014 01:31
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Anyone else preordering a Eagle Tree Vector? Full color OSD, super fast updating horizon, fixed wing stability/autopilot, and multirotor flight controller support. It also handles voltage step downs for 12v. Tower hobbies has a $25 coupon now and on their site it is like 237 before the coupon compared to nearly 280 on Eagle Tree's. Can't wait to ditch the Naza. It supposedly will ship the end of this month, but we will see. The only issue I see is apparently it doesnt have return to land only return to loiter on the multirotor. A shame but they've mentioned it is something they could do on a software update. The color is a gimmick but you can apparently reposition the UI and setup colored warnings and audio warnings which seems neat. Multirotor https://www.youtube.com/watch?v=Ka9AqyLIf2A Funjet F18 Sim style https://www.youtube.com/watch?v=uB8LDlTGtjQ
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Apr 8, 2014 06:15
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