Warning! Water can kill your vacuum cleaner instantly. I did get a little spill in the dust tank, meaning this design is experimental. Keep bottle and hose upright all time during cleaning, and check dust bag to be shure no water gets through. I recommend using as long and big bottle as possible, and keep at least 10 cm between water hose and air hose.

The setup. Tape around the bottle is to prevent it to implode. The Dyson nozzle fit without tape because of rubbery hose tip.

Electrical tape holds the hose that goes trough the bottle side. The self vulcanisation tape on the bottle tip seals the connection with the nozzle.

Some goo collected

Preparing the carpet with some random soap soloution.

Sorted after total weight and price as well.

Olympus EPM2

Weight: 424 grams with 9-18mm (269 grams without lens)

Price: Total: $1198 ($499: body, $699: lens)

Uses the same lenses as the Panasonic, eg. wide angle lenses are expensive. There are wide and cheap CCTV lenses up to 2/3″ but they don´t cover the whole sensor.

Pros: Digital image stabilizer
Cons: Expensive lenses wider than 14mm (28mm), no analog video out.

Panasonic GF3

Weight: 419 grams total (body, battery, card, 9-18mm lens) 264 grams without lens.

Price: $1048 ($349: body, $699: lens)

The micro four thirds cameras are small, under 300 grams, and give great video. The Panasonic can even be hacked to increase video bit rate and iso sensitivity. Lenses: 12mm (equals 24mm) is $799. The 9-18mm wide angle zoom (18-36mm) is $699. The $299 Rokinon 7.5mm is heavy and fish-eye. The Kowa 12mm is heavy as well with 270 grams.

Pros: Analog video output, great video quality and compression
Cons: Expensive wide angle lens.

Nikon J1

Weight: 402 grams with 6.7-13mm (277 grams without lens)

Price: Camera and lens: $898 ($399 – camera, $499 – lens)

Nikon´s new hybrid cameras comes with a smaller 1 inch sensor (compared to Panasonic 1 1/3 inch). This opens for less rolling shutter (Jelly-effect) and ability to use smaller lenses. I did some hard research to find a wide lens of 8 or 9mm. I wrote to CCTV manufacturer Sunex, VD-shop and avsupply. The latter gave me one interesting option: the Kowa 8mm f1.4 and other options from Kowa. You can get them from about $300 and up, but they are still pretty long and heavy.

Pros: 

• Less rolling shutter,
• Wide angle lens only 125 grams

Cons: 

• Wide angle lens a bit expensive (Nikon 6.7-13mm $496, equals 18-35mm), no analog video out

Sony Nex 5N

Weight: 357 grams with 16mm lens (287 grams body, battery and card)

Price: $819 ($571 – body, $248 – 16mm lens)

The Sony Nex series sets itself out from the bunch in a couple of matters. The first thing you notice is the slim body and the incredible screen with almost 1 million pixels. According to dpreview.com review, the camera is pretty close to the  Canon Mk II for dynamic range and iso sensitivity. But the most brilliant detail in my view is the small 16mm f2.8 lens. It gives that perfect wide angle of 24mm and is light weight – only 70 grams. It has a large APS-C sized sensor with a crop factor of 1.5. Despite it has little rolling shutter.

Pros: 

• Only 337 grams total weight,
• Probably the best all over image quality, AVCHD editable video format,
• Super detailed screen for focus and review

Cons: 

• No analog video out.

Pentax Q

Weight: about 270 grams with lens (241 grams body battery and card)

Price: About $320 ( $234: camera,  $79: lens, adaptors)

The smallest interchangeable camera available. With adapters you can use CCTV lenses in the same format as for the Go Pro, eg Sunex DSL355A-650-F2.8 4.16mm (24mm equal). It comes with stabilizer and lots of nice looking filters you can add to the video. The problem is the video compression and resolution, which is not up to par.

Pros: 

• Small, affordable, Analog video output, little rolling shutter, battery and memory card can be changed from the side, (no need to unmount the camera from the gimbal), sensor shift image stabilizer

Cons: 

• Not great resolution in full HD, low bitrate (12 mbit), small battery equals short battery life

And the winner is:

Sony Nex 5n. Best video quality, low weight, acceptable price tag. If you want something cheaper, try the Go Pro hero 2 or 3 black edition with the Sunex 4.16mm modification.

Nikon 1 With Pentax 110 18mm f2.8

After a lot of research on small cameras for my multicopter, I went for the Pentax Q. Affordable, compact, Pal video output, built in-stabilizer and only 250 grams total. I managed to find a nice wide angle lens from Sunex and everything seemed to be perfect.

However, after a few aerial video sessions, it became more and more visible that something was not quite what I expected from 1920×1080 video. There was something lost in the details.

Pentax Q With Pentax 110 18mm f2.8

Today I did a test to compare image grabs from:

1. The Nikon1 full HD video
2. Pentax Q full HD video
3. Pentax Q still image.

I used the same lens – Pentax 110 18mm f2.8.

If you look towards the midde of the circle and toggle between the images in the gallery, you see a slight pixellation on the Q, whereas the Nikon and the still looks detailed as expected. No matter the lens, the Pentax Q video lacks behind the Nikon and probably other cameras as the Go Pro.

This means I’m not yet settled with a small video solution for my hexacopter. Currently the only wide angle for the Nikon is the $500 6.7-13mm. It’s a bit steep, so I’m likely to put my attention towards the Go Pro Hero 3, wich has ABOVE full HD resolution.

The lenses are made for a notch smaller 1/2.5″ sensor and not 1/2.3″. That makes the lens covering about 9% less than needed. The result is some hard vignetting in the corner tips, but only when shooting full frame 3:2. Shooting in 16:9 mode on the Q pretty much eliminates it. Therefore, video shooting is unaffected, except when turning the stabilizer on.

Image quality:

The Sunex lens is a board lens intended for video cameras. You will get focus from maybe 2 meters to infinity without touching the lens. The barrell distortion is acceptable, but the image quality in large still images is a bit soft and there are some color distortion.

For video shooting, the lens is pretty decent. It provides enough details for the Pentax Q’s not so perfect video resolution at full HD video.

Here is a raw video test. Notice that the cross processing filter is on.

Full size images:

External test of the DSL 377 2.5mm:

I made a test using a kitchen scale and the OSD, transmitting the ampere usage to my monitor as I changed the throttle and gaining yet more thrust. I added some weight to the quad, giving a total weight of 2200 grams. The thrust was then simply 2200 minus what the scale showed. For example 1200 grams on the scale means 1000 grams of thrust or lift capacity. Here are the numbers I got for my four cheap Emax CF2822 1200 kv on Naza 10×4.5″ propellers, using 3 cell 11.1 volt fully charged 2200mAh battery:

Motor efficiency data for the FC 28-22 1200 kv brushless motor. Left colomn in the kitchen scale reading, then the Ampere reading, then the actual thrust. At right is the efficiency.

X-axis: thrust. Y-axis: efficiency (Grams per Ampere)

I measured the efficiency between 500 grams and 1700 grams in total, meaning 125-425 grams thrust per motor.

Quad or hexa?

The result is showing quite clearly that the more throttle and thrust, the less efficiency. This might speak in direction for using six or eight motors. Will the extra weight for two arms and motors eat up the efficiency gain you get? Here is the math: My quad with 5000mAh battery and 400 gram camera is about 1700 grams. Adding two motors will put on 180 grams for motors, arms, speed controllers and other. Lifting 1700 grams with Quadrotor setup will take 30 amps, giving 57 grams/amp (5.2 grams/watt). That´s 14.2 amps per motor. Lifting 1880 grams with Hexarotor setup will give the efficiency equal to 1250 grams on the graph. That´s about 65 grams/amp. This means 29.2 amps in total. That´s almost one amp saved. Not great, but it shows that adding more motors doesn´t necessarily take more energy.

Another calculation: If the quad total weight is 1200 grams, it uses 18 amps. Going for hexa is adding 180 grams. The thrust number for 1380 grams with four motors equals 920 grams with six motors. That´s 75 grams/amp. Giving 18.4 amps in total. A little bit more for the hexa then.

Quadrotor landing legs – skids vs foam

I did a lot of experimenting on the landing legs under my Quad. Everything i tried seemed to either bend or break. The only material rigid enough yet flexibe seems to be foam. I´m using round, 4 cm outer diameter pipe insulation. They are cut to about 11 cm long parts. The mounting is supported by a piece of pinewood screwed under the arms.

I enforce them with a tiptie around the wood where screw goes trough. In total the legs weigh less that 20 grams with wood and screws.

I though I´d order some landing legs from Hobbyking as well. They are cheap, just a few bucks, and looks good too. But weight is about 75 grams, more than three times more as the foam solution. Therefore I will keep my foam at this point.

Pinewood mount holds the pipe

This is how the HK 600 GT Landing legs looks on the quad.

Insulation foam mounted on the quad

The Panasonix LX7

video recording at wide angle (wider than 28mm). The list is under development.

Requirements: Less than 28mm optics, HD 1080P video, less than 400 grams total weight.

• Samsung EX2F $329, 24mm f1.4 wide angle, 294g + battery Focus: No manual focus
• Canon Ixus 220 HS $193, 24mm f2.7, 142 grams. Focus: Infinity mode
• Canon S100 $329, 24mm f2.0, 192 grams, focus: ?
• Panasonix LX7 $330, 24-90mm f1.1.4-2.3, 298 grams, focus: Manual
• Fujifilm Finepix F660 EXR
• Panasonic LUMIX DMC-TZ30
• Nikon COOLPIX S800c (25-250 mm)
• Leica V-Lux 30 (24-384mm, f3.5-5.9)

The lens at the Canon 220(Elph 300)is a little bit too soft for my taste (understandable for a 5x consumer zoom lens). It adds a little glowing effect on the videos. The Samsung lacks manual focus and is heavy.

My current bet is on the Panasonic. Very light sensitive at f1.4 and good external controls of manual settings and nd-filter. Pro video format AVCHD makes better files for editing.

If you want to go with the obvious, the Gopro 2 or 3 could be used. Low price, very light weight (especially if you make your own mount, not the heavy plastic cover). It has a decent sensor and with the new protune firmware upgrade, the raw video is great for serious post-production. No added sharpening and good latitude curve. Still there is one big problem with the go pro, and that´s the lens distortion. Fisheye has little to do with cinematic images and will make post stabilisation harder. Therefore it has to be removed as much as possible. The Gopro actually uses a CCTV standard mount, the S-mount aka Board Mount. There are two mentioned manufacturers for Gopro-compatible lenses, Sunex and Ragecam, but others could be used as well. Feeling Ragecam as a bit over priced, I contacted Sunex about Gopro 2. They gave me an

Sunex 377 2.5mm f2.8 lens for Gopro

interesting link to the DSL377 2.5mm f2.8. Featuring what they call “tailored distortion – “truer” and more natural wide-angle perspective over traditional wide- angle lenses.” As clear in the test chart below, the barrel distortion is much less significant, guessing that the right image is the GoPro original lens. Price is only $49 as “sample”.

The rest of the barrell distortion could be removed either one of this ways: Optics compensation filter in After Effects, Defishr standalone software, or the Fisheye Fixer from Crumplepop.

For the Gopro2: Sunex DSL377 2.5mm f2.8 at left. Possibly original Gopro at right.

The lens gives you a FOV of 119 deg diagonal (wide) and 90(medium) on the Hero2´s 1/2.3″ censor. That equals 12mm and 21.5 mm wide angle if the lens was rectilinear. Original lens is 170 degrees at wide, 127 at medium and 90 at narrow. This video has a test, showing the line bending.
. The little barrell distortion left can be removed one of these ways: Optics compensation in After Effects, Defishr stand alone plugin for PC, or the Crumplepop Fisheye Fixer for Final Cut X.

There is also an even less distortion lens recommended, the Sunex DSL355. This is the widest rectilinear lens from the company, at 4.16 mm, equal to 23.4mm in 35mm format. Just under the magic limit of 24mm. There is also the Sunex DSL 945D that is mentioned here. It´s a 5.5mm f 2.5. That´s a FOV of approx 69 deg, giving 31.5mm wide angle. Too little wide angle for me.

Other lenses for 1/2.3″ or larger ccd that seems nice on the paper:

• Towin electric 4mm 2.8 cheap?
• VD-Shop 3.5mm 1.8 (69 Euro)
• VD-Shop 4mm 1.6 (Not shure how much distortion it has – 39 Euro)

Since I got the horrific Conrad Arf 650 quad last spring, virtually unusable and unrepairable, I decided to make my own from scratch. I took the motors from Conrad and made my own frame from wood, later aluminium. I would recommend 10mm square rods as they are easy to drill and cut. To avoid getting bend rods in a crash, I mount them with zip-ties. The ties take all the beating. The main board is 10×10 cm aluminium and cork sandwitch, to be replaced with a single 5mm plywood plate. The plywood will take a lot of beating and never lose its shape.

The camera I prefer for this is the Canon Ixus 220HS. The camera is small, yet it has full HD video in 24mm wide angle. This a good focal width for good, cinematic shots. A lot of people are using the Gopro fisheye, but I’m not making sportsmovies. The image is transfered to the reciever with a 200mw 5.8ghz video transmitter. Unfortunately the range isn’t very good, about 50-150 meters. The rc control transmitter is going about 400 meters. VIbration dampening was another issue. I ended up fitting a rot to the camera tilt mechanism, attatching the battery in the other end. This is hanging under the quad in thick rubber bands, leaving no vibrations left.

Here are my recommendations after 9 months of diy frame building and testing:

• Rods: Aluminium, square 10mm
• Base: 10x10cm plywood, ziptie mounting the rods
• Vibration dampening: fit the camera and the battery to the same base, mount with short, thick rubber bands to the body. All vibration is gone.
• Propellers: Dji Naza 10×4.5″. Long lasting, little vibrations.
• ESC (Speed controllers): 18 or 20A
• Battery: 3 cell 2200mAh.
• Remote: the so called 9x. Great value.
• Video transmitter/reciever: something better than 200mw 5.8 ghz with stock antennas.
• Motors: 950kv approx. 15A. Currently using these. Very affordable, working good but needs to tigthen bolts regularly. Awaiting these in the mail.