'S T U F F'
Concerning the etheriality of 'stuff'
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Welcome to the Wasp!
This is my attempt at entering the 250 mini quad craze that's sweeping the hedgrerows & nocturnal kiddy parks of the world. I think it's a fair counterpoint to the more serious stuff of balancing thousands of quid's worth of multi-rotor bling in the air.
So bring on the fun & games!!
I have access through my job of work to some rather nice CAD design packages (and I have already dabbled with the excellent XTrackCAD) so I'm not a complete stranger to this kind of stuff.
I'm using a program called (Techsoft) 2D Design v2. It does everything neaded to produce a line drawing that is interpretted by the laser cutter (or cnc mill) to liberate the beatifulwee beastie from it's carbon sheet cage!
I soon found a shape I liked, and avoided re-inventing the wheel by adopting a tried and tested format of 3 main plates separated by stand-offs, and a 'clean' plate for the Mobius Action Cam.
A fellow multi-rotor enthusiast Richard Green kindly transcribed my 2D musings into a 3D mockup, which highlited one or two shortcomings!
Basically, the body was too small to accomodate the 1800 mAh lipo, and also the arms had become distorted when I attempted to stretch it in the software.
After the weekends contemplation, I have decide that I do like the shape of the Wasp, but I really need to finalise the finished size. I definitely like the idea of 62 props as oposed to the popular 5", and Richard has confirmed this in my mind when he informed me that he was getting 10 minute flight times (as oposed to an average of 5 by most folk's 5" versions).
I never knew this design malarkey could be so much fun! But it can get fiddly, once the basic shape has been desided upon, then comes the real hard work of scaling and proportioning everything, so it is neither too big, nor too small.
The bolt holes also need to line up properly!
Richard has worked extremely hard in this aspect, taking my basic design, and using his experience to reposition some of the mounting and lightening holes to best advantage, with his obvious eye for, and attention to detail. Bravo!
The Wasp! in prototype...
These are the first prototype parts, cut from a piece of waste mdf. Such is the nature of design & manufacture, we've already spotted an anomaly in the holes either side of the esc bays on the bottom plate, and have modified the drawing to correct this.
The next real step is to assemble all the hardware for the build, to see if it all fits and balances as a quadcopter should.
This is the 3D virtual of the current plan. You can see the size and position of both the 'Zippy Compact' 1800 mAh 3 cell lipo and the Mobius action cam, that is ideal for this type of craft.
Neat!
I thought I'd capture the essence of the manufacturing process. I never tire of watching amazing technology in action!
Below is a picture of the 'Wasp!' after production
And another....
Progress at last. Holiday out of the way, and it's full steam ahead. Here's the PDB (Quanum from Hobby King with 2 separate 'clean' outputs, one 12v the other variable).
I have removed all of the 3mm bullets as I deemed it better to solder everything, once I have determined the motor rotations etc.
Wiring up underway...I think these PDB's are excellent for the money, they make for a very tidy installation, as well as providing a clean power source for AV gear.
I put a meter on the output from the 12v output, and found it to be just over 10v, so either my meter is crooked, or something is slightly amiss. Either way, it won't affect anything as my Vtx accepts anything from 7-22v.
Since taking this picture, I have been away on holiday, finished building the Wasp! and succesfully maidened it! So I will attempt to rewind a little and take you through some of the processes and learning curves that lay in between.
Firstly though, here's the footage I took of the 'epic' maiden :-)
A slightly chaotic side view reveals how tight cabling can be in these mini's. So the first thing I will revise when my G10 frame version arrives hot off of Richard's cnc cutter, is to rejoin the esc data cables. For the CC3D (as with a lot of open source FC's) only one BEC needs to be attached, so the other three esc + & - wires are ommited. I decide to preserve the plug crimped ends when I extended my cables (cause the standard ones are too short). On the next incarnation, they will be cut off, so the join can be much smaller, so in turn will bend clear of the lipo.
I also modified the cable holes on the top plate, so the wires will now pass in front of the CC3D, again, to stay clear of the front end of the lipo.
These are small mods, to the casual observer probably trivial, but when you design these things, it's the small details that I believe make for a great design.
Here's the underside, I just love the look of it, somehow reminiscent of a 1970's toy. I guess it's the perspex that does it.
The second modification (and may be modified again at a later stage if necessary) was to reduce the lightening holes in the arms. They were simply too large, and created an unecessary weakness, which snapped when the quad dropped from about 6-8 ft! I'd sooner the arms break than the body obviously, but they simply wren't strong enough to cope with the sort of abuse these things get.
Some advice I picked up from the Open Pilot website.
was to twist the motor cables together, which provides a stronger overall cable, and also counteracts some of the stray magnetic fields that can interfere with video transmissons, so good advice that I have ignored!
Viewed from above, it's all pretty much assembled. I opted to use the Mobius mount which I got with the camera itself, which only adds a few grams to the overall weight. I had to secure it with tape until I sourced a bolt to lock it down. It's a 1/4" UNC in case you were asking, standard tripod mount. I cut down a bolt, but I did have the idea of using a plastic number plate bolt, but was told they may be metric thread, so unsuitable. I may still check one out anyway.
I aslo utilised the USB audio/video/power cable that was supplied, but I have not powered the camera from the flight pack, nor connected the audio, but it works very well. I should say here that the video stream does have a fractional delay, which a lot of fpv'ers would find unacceptible, and may indeed prove to be the case for me, so to that end I asked Richard to include a front plate for cmos cam mounting in his final draft.
The final mod was a late one,
I also decided to change the shape of the camera 'clean' plate to that of an oval, more aesthetic than purposeful I guess, but hell, this is art man!
So it's now in the air, and the fun can really begin, although it's not without pain! I've already broken two arms and a couple of 6" props, but more to bad luck than anything else.
I'm also getting to grips with the Open Pilot GCS software which I'm finding to be very logical, with a nice graphical user interface (GUI) to play with. The other contender flight controller wise is the Naza 32 (Acro & Full) the prices of which have dropped staggeringly since release, due in no small way to the proliferation of the things by Hobby King, who are selling them at the princely sum of £13. I have taken the liberty of ordering myself one, and I've also ordered a spare CC3D 'clone' from china, also at a bargain basement price of £15.
550 grams AUW so far, and that's using perspex as the main construction material, so G10 (firbreglass) or even carbon fibre would reduce even further. An alternative Wasp! would do away with the top camera plate & mobius and utilise a 700tvl cmos camera mounted to the new front plate, probably saving another 50 grams possibly. Less weight means more time in the air ultimately!
Of course there will always be an optimum weight for these things, too heavy and they are like lead, too light, and could have issues flying in any kind of wind.
Update:
Back in black!
Unfortunately, since my last posting some weeks ago, I have managed to lose my Wasp!
First model I have lost in over forty years. Mind you, I haven't been flying for the best part of thirty five of them, still it's not a nice experience, frustrating and irksomely expensive, and such a waste of decent kit.
Oh well, it was still in the prototype stage, so I have now arrived at the picture you see on the right. We have modified the arms, beefed them up in fact, and the latest incarnation uses 4mm carbon, so would appear to be virtually indistructable.
I have managed to replace all the hardware, except for the Mobius, as I may see if ebay can help me out with this. As you can see, the arms are looking more like superman's eating utensils, lets hope they do the job.
Did I mention I went for all holes slotted? THis was because I discovered that the motors are handed, so the wire exit positions are awkward on two of the motors.
Here it is looking suitably 'busy', I've even added lights on this one! I figured that anything that makes it easier to find is got to be a good addition. I do like these Quanum PDB's, I can set the variable to 5v for a supply for my 5v fpv cams, whilst supplying my 12v Vtx with a clean supply.
I had the idea to drill two 1.5 mm holes through the plate for the led contacts, which made it quite neat I thought.
Here's where I'm at with the Wasp to date. It's now January 2015 and before Christmas I updated the firmware to the latest on the CC3D, namely 'MIni me'. Even my piloting skills can appreciate a more locked in preformance, maybe more akin to the Naze 32, that has become the defacto FC for the 250 class multi. I have been back out again with her, and had a near miss with my DYS 1080p camera, that was held precariously on the front of the craft! Oh well, I managed to find it next day, in the damp hedgerow, but was none the worse for its enforced 'night out'.
I spent a very nice hour in the woods, threading my way around the trees, until about my forth crash put payed to a couple of the plastic hex posts that hold her together. I have resisted putting her back together, as I really need to invest in some metal fastenings. Plastic is great for absorbing the impacts, but is a little too breakable for something that is hitting solid objects as a matter of course.
A new look at the Wasp frame
Having had a little time away from flying multirotors (and all the better for it) I decided to look again at my original mini quad frame again, with a view to making some improvements. Not that I have been dissapointed with its performance, quite the reverse, and it shows just how easy it is for anybody with very limited knowledge of aeronautics to be able to put one of these things together, although in essence, it was as much a lesson in getting my ageing head around CAD design as anything! The side benefit was that I am now a lot more confident about sketching up components for my various other model making projects.
So, what to modify? That was the question! Well, firstly, although I designed my 'Wasp' for both 5" & 6" props, in truth, I much prefer the handling of 5" props, both indoors and out in the field, so first thing was to reduce the length of the arms. Secondly, I wanted to reduce the number of fixings involved in its construction, so making a one piece bottom plate with integral arms ticked that particular box. To add strength, I decided to beef up this new integral frame member, by adding a contoiured bottom plate, which in effect doubled up the arms. As I have access to a laser cutter, my preferred material is Delrin, being both tough and relatively cheap (from USA), but it needs to be slightly thicker than both carbon or G10 (fibreglass composite).
I think you can see from the sketch-ups, that the top plate now stops a few cm from the front of the quad. This is to accomodate the GoPro size camera in its new, more balanced position on the middle plate. On the right, you can clearly see my idea for the integral body/arms. If it were being made from carbon fibre, then I believe two 2mm bottom plates epoxied together would suffice, or of course, if it were being machined by cnc cutter, then it could of course all come out of a sheet of 4mm carbon!
I think this woiuld be favourite, but I'm attempting to be a little self sufficient in my workings, so Delrin cut by laser will likely be the route I take.
I've since made a couple more mods..
I removed some of the unnecessary wire routing holes in the middle plate, simply enlarging the remaining hole in the middle to get more through.
This will give more space to fix the reciever behind the gopro.
I have some etching on the top plate, for 'branding' and also my phone number will likely appear, maybe with the word 'Reward!'
I've also incorporated it's name into the frame where the airflow holes for the esc's were. cool eh?
A side benefit of Delrin, is that it can be tapped, which opens up further ways of reducing the parts list!
Which flight controller to use?
As the title suggests, I think I should mention, that in my latest incarnation of the Wasp, I have decided to experiment a little with flight controllers. I'm perfectly happy with the CC3D, which is a 32 bit FC, but such is the market in these 32 bit controllers these days, it often pays to shop around, and so a few months ago, I purchsed a Naze 32 'Acro', which is the basic version of the Naze family. I have fitted this to one of the new wasp frames, and am experimenting with firmware until my now integral arms/bottom are fabricated on the laser.
The prices of these controllers, can be sub £20, in fact my latest acquisition a 'Flip 32+' was c £17! That's incredible value for a controller which is, in all but detail, a clone of the Naze 32 'full' version, meaning that it has the added functions of a magnetometer and barrometer, which make it more 'aware' of its surroundings in space, and so more acurate to fly. THe Naze 32 'full' currently retail's at around £30.
I have decided to skip any background to the controllers, it becomes a little enshrined in politics of and the ego of the software developers, so I will just outline the differences of the three controllers, and their respective firmware & GUI options.
Basically, all the 3 controllers are 32 bit. The CC3D is a 6 degrees of freedom (6DOF) meaning that it has a gyro and accelerometer onboard.
The Naze 32 acro & Flip 32 are also the same.
The Naze 32 (full) and Flip 32+ (the one I have) are all 10 DOF boards, having the advantage of an extra two sensors, a magnetometer, and barometer, giving 10DOF.
So, I have three versions of my Wasp, a CC3D, a Naze 32 acro, and a Flip32+! Confusing huh? I intend to send one of them to my brother in the States, but I first need to set it up so he has a flying chance of hooking it up to his RC gear (pardon the pun).
I will likely send him the Flip 32+, as its extra sensors will make it more stable, and maintain altitude when moving forward, instead of having to make constant changes to throttle like the CC3D & Naze 32 acro.
Here's a comparison of the old and new versions, on the right, is the new v5, nicknamed 'The 'Milky Bar Kid'.
I like Afro's!
As yo ucan see, I've done away with the case (which is a theme of this v!) and mounted the FC (in this case a Naze 32 acro) just below the top plate. I will likely cut a clear lid to sit on top, to further protect the delicate electronic brain.
I've placed the Spektrum satellite receiver here too, to give an idea of perspective.
This is another feature I'm trying out, as I have a couple of spare satellite Rx's, and they take up much less space than a conventional Rx, and also allow the use of CPPM from a Spektrum Rx, which is not normally an option.
All three FC's are capable of utilising the satellite's, but in varying degrees of complexity.
It's one reason I bought the Flip 32+, as it has a dedicated satellite port, which just needs either a jst micro socket soldering on, or simply solder the wires. (see note * below!)
It's looking nice, and I intend to make the cabling much neater on this version.
Incidentally, my new motors arrived a few weeks ago, I decided to try the emax 1806 23000 kv plastic motors, yes, plastic!
Now, I had a little trouble with the Flip 32+ firmware, but I blame myself entirely for that. Basically, the firmware is interchangeable between the three boards, as I discovered. I originally used the Multiwii 'Win GUI' to hook up the Flip 32+, but got an error message about a mis-match of firmware, despite following the instructions, I must have managed to flash with the wrong firmware, and the board stopped responding.
I resolved this issue, by running the STM flash loader demo software, shorting the two boot pins, and then flashing with the latest Baseflight .hex file. I since discovered, that flashing the boards from within the configurator's removes the need to short the pins, but at least it's a way back, if you get confused. This chap has an alternative method: OscarLiang.net
It's impossible to say exactly what I did wrong, so won't dwell on it, but this is where I started out MW-WINGUI
The Flip manual can be found here: Flip 32+ manual
The 'Baseflight' firmware can be found here: Baseflight FW
The 'Cleanflight' firmware, and general info into the wonders of this breakaway version of firmware for all of the STM32 boards can be perused here: Cleanflight
I should add, that both Baseflight & Cleanflight setup routines can be accessed using either the Baseflight configurator, which is a Google Chrome app, or the parallel Cleanflight configurator, both from the Chrome app store.
Just search in Google, then click 'add'.
I had made some mental notes over the past year or so concerning Baseflight & Cleanflight, so using the GUI's wasn't a total shock. A lot of the more complex features can be accessed or modified by typing in simple commands in the inbuilt CLI interface tab. Exiting the CLI always reboots the board, saving the settings in the process.
I guess it's always advisable to back up your settings before you start to meddle, just in case the innevitable happens!
I
I decided to mount my Flip 32+ upside down, so needed to alter the roll & yaw 180 degrees, to trick the FC into hinking it's the right way up, sort of.
You can see a list of all patrameters by typing 'dump' in the CLI. On the left, note the 'set align_board_roll = 180' and also the yaw command. Just type them into the CLI, hit enter, then exit to save the config file to the FC and reboot.
As the Micro USB Iis facing forward, I may chose to rotate yaw 90 degrees, to make it accessible from the side instead.
:-)
18 March 2015
Note *
The fact that the Flip 32+ board has a dedicated 'port' for the satellite Rx is a trifle misleading, as although the version I have does have the 3 pin outs for signal, ground & +ve, apparently, it shares the same UART port as the USB connection! I have discovered that there is a newer version of board that has the 3 pin socket provided, which one asumes does not share the USB channel, so will work as a plug and play unit. You may well still need to configure the satellite Rx properties, and of course bind it to your Rx as well.
On the binding aspect, I have now managed to get both my Spektrum satellite, and Lemon DSMX satellite receivers working interchangeable on both Naze & Flip boards, after a bit of a faff, mainly due to very poor documentation.
I found that a bind setting of 7 worked for me, which roughly translates to Dsmx 22ms latency 2048 bits resolution.
You also need to configure the port tab for USArt2 for serial_rx.
I have left the orientation as it was, as rotating it 90 degrees puts the motor output pins in conflict with the frame standoffs!
Here's a few pics, just showing how things are hanging. Above; the tiny Lemon Dsmx 2.4 Ghz Rx in situ.
Below; the PDB, emax motor and a couple of the cheap 600/700 tvl ccd camera's that I seem to be amassing!
Oh dear, I seem to have bought another FC!
21/04/2015
I can't seem to resist buying theses things, so I'm perhaps begining to understand why women buy so many earings!
This is the CC3D 'Atom' FC, which has been around for a while, but has just become eminently affordable from China, mine cost me around £10 including P&P!
Interestingly enough, I read that they are shortly shipping the 'Revo' version, which has a few more bangs and whistles, for around the same price, so I will doubtless be unable to resist this one either.
05/06/2015
Update!
I've managed to spend a little more time with my 250 project, somehow, and have finally got one of the new Delrin frames assembled and in the air! Yipee.
I'm impressed with the feel of the Naze 'Acro' FC, it does inded feel slightly more 'locked in' than the CC3D, but I suppose that is simply a difference in the firmware, and out of the box flight characteristics.
I know full well, I could 'tune' my CC3D to be the same, but A: I wouldn't know where to start, and B: they are easy to 'break' setting wise, as my pervious CC3D developed a slight tremour that I couldn't eradicate.
Picture time!
Here's the wiring, before I added the LED light bars front and back, in my now customary fashion.
Of course, when I'd assembled it, I realised that I'd left out provision for the 5v & 12v 'clean' feeds!
All fired up! Ready for the maiden, which went flawlessly. I like flawlessly! You can see the Lemon satellite rx stuck underneath the front of the top plate.
18/06/2015
Here is my jpeg render of the latest incarnation of the integral version. You can see the slots I've just added (in red) which should accept the mounting part of a standard GoPro 'Frame'.
Easy.....!!
Here it is, in kit form. which is destined for a friend. To that end, I dry assembled it, to make sure everything was tickety-boo. That's when I discovered a slight (1mm) error in one of the fpv cam mount slots. I've since modofied it, and will cut some more as and when I get the chance.
It all goes together very nicely actually, but it's surprising how tricky it is to work out the most efficient method of construction, if you were producing a guide for instance!
Still, it is easy, but loads of fun, putting together things that you've designed from scratch, certainly makes you appreciate 'things' more!