30 January, 2011

Zăganu - 01 Introduction

OK, so after some words in the previous post about all this project wants to be it's time to get into the serious stuff. There are so many things into such a major project that it's hard to put things in order. Spent my last two weeks just surfing the net and trying to assimilate as much info in the field as I could since I'm a newb in all this RC hobby.

Except the documenting phase there's also a lot of acquisitions needed, from the Tx/Rx system, batteries, motors, ESCs, BECs, frame and so on. From all these I'm sure about this:
  • I'll make the frame DIY style, using 10x12x1 rectangular aluminum hollow tube for the motor arms and carbon fiber or FR-4 plate for the center part
  • I'll go the cheap way with the motors, propellers and ESCs since they are prone to destruction during trials. I've already ordered ESCs from the giant HobbyKing, the props and motors I intend acquiring from local suppliers
  • For the flight controller I took the MultiWii path with some modifications. I acquired the original Wii Motion Plus and Nunchuk controllers as to avoid any problems with the cheap replicas. I'll try implementing the actual controller on a LM3S3748 development board I already had. If that doesn't work out then I'll switch to the Arduino approach with the software already available
  • for the Rx/Tx system I went for Hitec Aurora 9 which is quite a lot over average but it should make my life a lot easier with all it's bells and bells and whistles. 
 As for some quick links on the subject, here are a few that I really consider essential:

So now I've sketched the frame and it's as ready as it can be till I get the rest of the components. I've also hacked the Wii controllers and successfully communicated with them over I2C. That's about it for now, I'll come back with some pictures and details on my work in the next post.

27 January, 2011

Zăganu - the start of a dream

According to wiki, Zăganu was a species of big eagle that once lived in the mountains of Romania. But I'm not going to talk about this here. Zăganu is just a name i took and gave to my latest project and the only thing that has in common to the bird is it's the flying abilities and the big size.

So.. to cut it short and get on topic, I'm actually talking about a RC multirotor helicopter model. The idea ain't new, neither to myself as I've pondered on it for some time now, and neither to the rest of the world, since there are many projects out there on the subject. Most of them started in the RC model community but the apparent simplicity of the idea made it a wildfire through every hobbyist of one kind or another.

What really got my attention was the photographic opportunity that these machines offer. I first got the idea seeing some BTS movies somewhere on the net with video cameras mounted on RC helicopters. The problem with classic helicopters though is that they're quite exclusivistic in the sense that the hardware involved is quite complicated with lots of moving parts on one side and things that need to be fine tunned on the other, and besides all this, in order to fly a heli you do need some serious skills and practice. The quick way out of this are the multirotor helicopters where all the fancy mechanics and serious skills move to more than one rotor and some sort of controller electronic board.

Most of the multirotor designs involve tri or quad motor designs as they are somewhat simpler and cheaper to build, but when you have and expensive and hefty payload like a DSLR camera then a hex or octo design is best as it is a more stable platform. Since a DSLR is my ultimate goal for such a flying machine I choose starting with a quad design for testing and tuning of the controller and then expanding to octo for the final "product". I'll stop here for now and get back with details as the work continues.

10 January, 2011

Nixies and Mitino Radio Market

Well, some of you might not even know what the tittle is all about so let me put some references about nixies. Pretty cool, right? I was always found about that electric shine. The problem is that nixies are history and the only way you can put your hands on something like this is if you salvage it from old equipment or buy it from fairs or even the internet.

Mitino Radio Market
Nixies recovered from an old equipment
Had a few nixies back home donated by a friend of mine but I wouldn't mind getting some more. In a business trip last year I strolled through what I later found out was the famous Mitino Radio Market. I was on the run looking for a megohmeter and some other tools but I couldn't help not noticing one store's showcase. It was packed with nixies, all shapes and sizes. Sadly though I didn't have time for it and the shop was closed any way. After my trip was done, on the way back home, having some extra hours between flights I hopped on the Aeroexpress, changed it for the sub, added a hefty part of walking and I was back roaming the Market. The place is awesome, a lot more shops than I first saw. Anything you can imagine in the field of electronics is there, from car audio and GPS units, to motor rewinding shops, custom battery pack manufacture shops and electronics antiquity shops.

 I went in the shop where I first saw the nixies and this time it was opened. The prices for a piece were insignificant and took quite a few. Bargaining with the seller wasn't a problem since he was patient with me and my flourish. Left the shop with literally a bag full of nixies and VFDs for no more than 15$ or so, quite a bargain I'd say.

Once I was back home, didn't have the time for them so I postponed a close eye review. Now the time came so here are some close-ups:

 The biggest VFD of them all was what looked like a clock display. Sadly it can't be used because the envelope's evacuation tubeglass was broken either before I bough it or while I transported back home. Once the vacuum escapes the envelope it's no longer a V in the VFD so it will definitely not work, hihi.. Another piece for my little electronics history museum.

VFD with evacuation tubeglass broken (right side)
Even though brand new these little wonders are ancient stuff but with a little Google on the search, a little Google on the translation, I got the tech infos I needed in no time. Russian hobbyist keep pretty good records of all mother Russia had to offer in it's glory days.
Now all I have to do is develop a HV supply, draw out a schematic, figure out a purpose and above all find the time to do it all. So.. back in line on the long list of not_have_time projects of mine.

09 January, 2011

Lambency 77mm White Balance Lens Cap

Recently it keeps bugging me about all this color management thing when it comes to digital photography work-flow. Back in the old days, everything was straightforward and hard codded, now in the digital era, everything is virtual and relative.
What I mean here is that unless you take special measures, by default, taking and viewing an image won't show you anything else other than a bunch of assumptions. The camera you took the photo is assuming how bright and what color tones the scene must have had, the monitor assumes what that picture file should be displayed as and if you print it, then the printer takes it's own assumptions.
To cut it short and get on topic,  preoccupied by all these assumptions and having problems with some inconsistent results, I tried to put some order into things and started with the most basic step you can take, the white balance.

The theory is pretty simple. Most respectable camera out there offers the option to set a custom white balance level based on a sample photo taken of a gray card or alike. Since I wasn't so found of the gray card idea, I choose the alternative, a white balance lens cap. Basically it's a lens cap that has an extra transmissive window in it that the camera can picture and consider for the custom white balance.

My fault was to grab whatever came first and trust the retailer, so I stopped on a so called Lambency 77mm White Balance Lens Cap. "so called" because after unwrapping it I couldn't find any reference about Lambency producer on the package, nor any other producer for that matters. Chose the 77mm because it would suit two of my four lenses.

The quality of the product is plain modest, cheep plastic and bad taste golden ring around the window. The fixing mechanism on the lens is the same as that of Nikon lenses. Took same test shots around the house and it did correct my incandescent light fairly well. Must be noted that in order to get the test shot with the cap on you need to set the lens on manual focus.  

The worst complain about this product is that it broke the very next day after I got it. While being on the camera in my backpack, the translucent dome came off. It turned out the locking mechanism was poorly designed and it broke with no way to put the dome back other than glue it back with a plastic hot glue gun. It's not a fix that will solve the problem for good since it's prone to failure because of the dome design that sticks out.

Conclusions:  attention, attention, attention.. Not to jump head first next time. I'm not sure how much I'll use this product from now on since I lost my trust in it and I already plan on getting a more reliable color checker board.

03 January, 2011

NiteRider Pro 1400 LED

NiteRider Pro 1400 LED
UPDATE: NiteRider Pro 1400 LED is now replaced by NiteRider Pro 3600 series

Just before the winter holidays started my latest obsession was finally in my hands, muhaha!! Yes, it's the new NiteRider Pro 1400LED bike headlight. Ever since I've seen it while surfing on Amazon I knew I must have it. Awesome specs, good reviews and huge potential to be the ultimate light source for all my outdoor activities: biking, caving, mountaineering and even photography.

So now that the holidays are over and I had the chance to put it to test in all the above mentioned activities, I can sit down a little and tell you all a little about this amazing product.

NiteRider Pro 1400 LED box back

NiteRider Pro 1400 LED box front
Starting with unpacking.. As I already knew from the reviews I read on the net the light came in a pouch with everything packed in really tight. So tight that once you get all the parts out, it's hard to put them back together to fit the pouch.

NiteRider Pro 1400 LED storage pouch

NiteRider Pro 1400 LED unpacked
Together with the light I also got the NiteRider Explorer Headband which is needed for using the light as a headlight in mountaineering or if biking without a helmet. The headband is wide enough to handle the 200 gr weight of the light head and offers 4 plastic hooks to aid cable routing to the battery pack. Wearing it I did get a little bothered by the head pressure caused by the light head support pressing. I guess more padding would have been needed but it's something you get used to.

NiteRider Pro 1400 LED headband

NiteRider Pro 1400 LED headband wrapped
First thing that stroked me after looking at the light head was the fact that it didn't resemble the picture on NiteRider's website. That's because the picture there is actually of a Pro 1200 light system. The difference between the previous Pro 1200 and the current Pro 1400, besides the actual light output, is the presence of two light pipes, one for each reflector. You can see them in the first picture as two small dots. Their purpose is mainly when using the light on a bike, to show you which reflector is turned on. The actual LEDs inside each reflector are Cree XLamp MC-E.

NiteRider Pro 1400 LED light head turned on

NiteRider Pro 1400 LED light head

Moving on with the close eye inspection, I checked the cables and the connectors. The cable is very thick and rugged and the connectors well build. They are trapezoidal in shape with a flat matching key, they lock securely and offer quite good water proofness. The only problem that i could see is extra caution needed when connectors are unplugged/plugged in dirt/wet filled environments.

NiteRider Pro 1400 LED connectors

The battery pack is the biggest and heaviest part of the system. That's usually overcame by fixing it on the bike frame or caring it in the backpack, keeping it in a pocket is very uncomfortable. Quality is great, rubber pad for fixed mounting on the bike frame with Velcro straps that can easily be removed if you want to gain weight and space in non-bike activities. I wanted a little more info about battery pack maintenance so here are the producers recommendations:
When charging the battery, it should be done inside at room temperature. The batteries should not be charged below or above certain temperatures. There is a safety circuit that will shut off the charge if it is in such temperatures. For long term storage, it is best to store the battery at about 40% charge. If you are storing the battery for longer than a couple of months, it is best to store it at 50% then, about once every six to eight weeks, fully discharge, fully charge then discharge to about 50% for storage again. 

NiteRider Pro 1400 LED battery mounted

NiteRider Pro 1400 LED battery and cradle
The helmet mount will only work with vented helmets. It uses two straps that need 4 frontal vents in the helmet to get a fix. It won't work on most full helmets or a climbing helmet like my Petzl Elios, since the need of the Explorer Headband.

NiteRider Pro 1400 LED helmet mount

The handlebar mount is pretty straight forward and easy to use. The material is plastic and not metal like I think i read on a website. Just in case you need it, it comes with an extra rubber pad and an Allen key.

NiteRider Pro 1400 LED handlebar mount

The unit also comes in with what one can call a docking station since it's more than just a charger. Besides the power jack and the battery cradle, the unit also has an mini USB port and a connector to plug in the light head. You do this to program the light head with custom user light patterns. One thing I don't like about the docking station is the empty plastic case feeling. I've seen one unit opened somewhere on the web and it's a certain fact the unit is not the smallest it could be and that is really important when traveling.
The great thing about the power adapter is that it has universal input (100-240V/50-60Hz) so you can use it anywhere and the voltage output is 12V which means you can use a car plug adapter to power the docking station when on the move. A diode or two might be needed to create some voltage drop and get a true 12V output but that's something left to be seen.

NiteRider Pro 1400 LED charger bay

NiteRider Pro 1400 LED power adapter

Besides all these hardware aspects there's also the software side. The unit has 1 factory program with 3 light levels and 1 flash pattern and 4 user configurable programs with at most 6 light levels combinations and 6 flash patterns per program. That sounds like a lot of fun when you first think of it but at least for me it turned out to be more than I needed so I ended up using only 4 light levels and 3 flash patterns for 3 of the programs.
In the flash window you can even set a custom flash pattern with 0.05-1s on/off time. This pattern is shared between programs so only one given custom flash pattern can be used at any given time on the unit. Also about flash patterns, even though you can set 6 patterns per program, there are only 5 distinct options to choose from so you either use the same pattern on two slots ore never use one slot.. that's a little awkward right? Maybe a second custom flash pattern should be there, right you guys from NiteRider?
One thing worth noting even if it's pretty much irrelevant is that on high speed flash patterns (like 0.05 on with 0.05 off) the light head's on-board controller doesn't keep up the count and lags a little from time to time.
The software that does all these is great but could have been better still. I'm not a fan at all for the applications with custom skins like this one and I don't understand why the Light window layout is one way while the Flash window layout, even though houses the same 6 settings style, is the opposite. Maybe I'm too fastidious..

Mods and tweaks
During prolonged bike tours in the countryside I considered some anti theft measures like replacing the battery pack's Velcro straps with plastic cable ties and replacing the "user friendly" screw and wing nut on the handlebar mount with an Allen head screw and a washer.
When I installed the Universal Handlebar Mount I noticed that the light head fixture wasn't adjustable like the helmet or head mounts. This meant that vertical adjustment of the light head had to be done by unscrewing and then tightening back the whole handlebar mount which is totally uncool. Salvation came from the helmet mount from which I took the light head support and switched it with the one on the handlebar mount. It's not a perfect switch since the systems are a little bit different but it can be done with no intrusive maneuvers in no time.

Official documentation
Prior to getting the real deal, the one thing that really bugged me was that the user manual on the NiteRider's web site didn't work. Hope I'm not breaking any rules but here is the scanned documentation that came with the unit.

As I've said in the beginning, these holidays i had the chance to give the unit a spin in all sort of activities. Used it in the cold, in the warm, when dry, when wet, low beam, high beam.. you name it.
First things first so I'll start with biking. Handlebar mounting wasn't a big thing, finding room for the battery pack was. The frame's down tube was already busy with the water bottle support that housed the AirZound Bike Horn so I had to squeeze the battery pack above it really tight. Since it's winter here I only had the chance for a quick 20 km city and surrounding trip. Light output is definitely enough for every need you can possibly have while riding and it's definitely more than you need within city limits.
The most annoying thing here is that you don't have enough control over the flash output. By default it is 700 lm on the flood reflector and you can't do anything about it. Why use the flood reflector? beats me cause it's definitely not something that you want to do with a 700 lm light source in traffic, where auto drivers freeze into panic when they see it but might just as well stop and beat the hell out of you.

While on the mountain I used the unit as a headlight. I tried using direct connection of the light head to the battery pack with the pack placed in my backpack's top pocket but it was to short so I had to add the extra extension. It put to shame my now discontinued Petzl Myo XP headlight and on paper it's far beyond the Petzl Ultra even though I didn't have the chance to see them side by side. For both biking and mountaineering most of the times I used 150 lm of spot light, adding extra only when needed.

I also had the chance to explore an old mining tunnel which was the only case when I felt flood light was better than spot. Having such a great light in  total darkness is a blessing for taking photos as it helps you find subjects to photograph, helps the camera auto-focus and can even be used as main light if no flash is at hand.
One thing that got me a little worried was the fact that while in the tunnel I actually heard the buzz coming from the inverter driving the LED's in the light head. When these switching power supply commutation noises can be heard it usually means somethings shaky inside, a coil or transformer not properly tightened. The noise disappeared once I was out the tunnel and haven't heard it since so it might have been a combination of factors like temperature and moisture (since the unit is not rated completely water proof).

All and all, the most important thing that must be kept in mind when dealing with this unit is the company's motto "Technical Lighting Systems". It is intended for off-rode night bike trips but it's definitely not worth the money if used just for that. You have a lot of light output, battery power and build quality but you loose something in the way whenever you turn sideways from it's main purpose.
Within city limits it's to big and heavy to use, it draws a lot of attention and changing from lighting to flash is not something that can be done easily while riding. That's why I won't give up the old Trelock LS330 which is perfect for the job.
On the mountain is just great on off-track trips to help you find your way into the night. You can spot tracks and signs that are hundred or thousands meters away which sometimes is a real life saver.

Am I happy with the purchase? Definitely yes! Could it be better? Definitely yes! Would I buy it again? I'm not sure..