søndag den 12. januar 2014

BradWII firmware

I´ve read a lot of stuff lately on quads and yesterday when i searched Google for the term "auto pid tuning" it mentioned Bradwii, clicking on the article, i found a firmware coded by this guy Brad, part of his code was ported from Multiwii. The intresting thing about his firmware was what it has to offer.
Take a look at this list:-

- Level, Acro, and Semi-Acro flight modes. - Multi-Wii Config compatible (including bluetooth apps, etc). Works on any (and multiple) serial ports. - Simplified settings means there are fewer things (especially PID) that need to be adjusted. - Auto PID tuning! - Position Hold - Mag Hold - Altitude Hold - Return to Home - Standard or DSM2 Satellite receivers - Throttle Helper - Automatically applies extra throttle when tilted in attempt to maintain attitude. - Uncrashability Mode - Takes over when you get below critical attitude or get too far away. Practice those Acro maneuvers without being able to dumb-thumb it!

Not bad...two things really wanted me to try this firmware, the Auto PID tuning and the Uncrashability Mode, if i could run on a correctly PID tuned quad and have the ability to fly without crushing all the time, it would give me some valuable flight time.

unless you can program, the firmware currently runs on these three Hobbyking boards:

- Multi-Wii Pro 2.0
- Multi-Wii 328p
- Multi-Wii NanoWii

No libraries are required to flash the firmware and flashing the firmware is done pretty quickly compared to MegapirateNG, only one file has to be edited and that is config.h,the Bradwii har support for bluetooth and GPS, but my Gimbal was not coded in the software so had to loose that. After flashing. It can be run on MultiWII GUI 2.2.

Took my quad for a spin in the garden where i had my previous crashes in the neighbours garden and with the default settings the quad was very stable, didn' t try the auto PID tuning as i might require more space than my back garden. Must say i am pretty impressed, found a soccer field and here i gained some good flight time, no broken props, and gave me a chance to learn flying. Very stable and quick to trim. This is a good beginner firmware.

Look at this site for more info on this firmware



Flight controller

Looking for a new Flightcontroller, well this site http://oddcopter.com/flight-controllers/ shows you the different controllers, their capabilities and a price comparism. Each controller is reviewed and a link to their rspective web page is also provided. Check it out quite a good site.

fredag den 3. januar 2014

Gain flight time by stabilizing your battery

Stabilizing the quad was for me a daugnting task, when i first powered the quad and tried testing it, it simply shook in all directions and was unflyable, searching the net, i read about PID tuning and have to this day still not mastered it correctly, but hopefully i will learn it at some stage. One of the main issues i had when i PID tuned and tested was that the quad kept drifting to the one side, i was convinced that this had to do with the PID tuning being wrong, as i thought that the flight controller would automatically compensate in keeping the quad level so i kept at it and never did find the answer until i after searching the internet i found a thread that explained this issue, after realising that it had more to do with the quads center of gravity, using the transmitt i trimmed the quad accordingly and was able to fly.

After some time of flying i got fustrated because i had to ever so often trim the quad everytime the battery moved this due to a heavy landing or simply because it wasn´t strapped down hard enough, i got extra straps, but the didn´t solve the problem.

The X650F frames comes with a small battery holder, which is almost impossible to stabilize the battery in the same position, so i decided to get rid of it.
After getting rid of it, i mounted the battery directly on the frame, used two velcro straps to stabilise it and that helped somewhat, but small movements still occured.
and time was still being spent trimming. I went down to the local fabric store and bought some velcro with tape on the opposite ends.
Taped some velcro on the battery mount and a bit on the battery. Mounted the battery and used the straps i previously had to tie it down and now my center of gravity is always the same, if you use different batteries you could align each battery and mark the spot, so you can place the battery at the same spot each time. 

If you have some other crazy idea let me know, it might be worth while trying and sharing with others....

A small trick to quickly mount and dismount your gimbal

Well my heatshrink finally arrived, time to get busy. The last time i flew the gimbal kind of fell apart, had to get my tools, unscrew the top housing to remove the wiring under the frame, remount everything before flying again, took about 10 minutes standing in the cold, too long...
So i wanted to find a new and quicker way of removing everything and though up something very simple, all you need are solder skills, even shitty ones like mine, a bit of cable, and two JST connectors.
The idea is to combine both + cables from the two gimbals and both - cables, connect the + them and add a wire thats long enough to reach the edge of your frame, at the end of the wire, do this with the - wire then solder a JST female plug, heatshrink the cables as you normaly would do, then add a coloured heatshrink on the outside.
The two signal wires from the gimbals are also fed up to the edge of the frame they are soldered onto a JST connector, remember to note which side is soldered where, as you will need to connect them correctly on the flight controller, i didn´t have an extra JST female, so used a power switch connecter from an old PC works fne. If you get confused and forget which was roll and pitch, plug the signal cable of the gimbal into one of the reciever ports, Throttle, yaw, ailiron or elevator, turn on your transmitter and move the sticks, your gimbals should react thus finding out which is which.

 The cables is then mounted into a JST male connector that is superglued on the frame, the left side which is the power, red for + and  black for -, has also been heatshrinked so  as not to confuse the two connectors. The right side is the signal, one for pitch, the other for roll.

The power cables are fed to your power source, in my case i have a UBEC where i branched the cables and have power for different units, like the flight controller, reciever etc.

The unit can be unmounted or mounted in 30 secs. flat

30. seconds later....

 The two superglued connectors run under the frame, the left  providing power to both gimbal and the right sendes the two signals, one for roll, the other for pitch to the flight controller.
Anyway just another crazy idea....hope you can use it....

onsdag den 1. januar 2014

From one novice to another

Flying a quad is not as easy as it looks, i usually go into my garden and  train my lifting off, hoovering in the same spot, then start manouvering around. As often, the quad may start to drift or i end up pulling the wrong stick so the quad goes in the wrong direction...then it suddenly ends up on its way over the hedge into the nieghbours garden...what to do panic...drop the throttle, the quad comes crushing to the ground. Upon inspection broken props again. Firstly if i flew the damn thing on an open field, then  i would have more space to learn...anyway rather than buy props from your local store, search Ebay for bulk props, they are adequate for learning and breaking and cost next to nothing, they are not very well built in comparism with other models, they are thinner and probably not balanced properly but they do help you learn to fly your quad keeping the cost at a minimum. i bought a set of 8 pcs Nylon 10x4.5"  Propellers for the sole price of $7 including postage, Hobbyking are relatively cheap on their props around $8,50, but then i have to deal with the $8 dollars charged for postage and the fact that the European warehouse often has no stocks available. My local store charges about $6 per prop, pretty steep price for learning to fly a quad.

Read extensive prop reviews and buy expensive props and propeller balancers once you have become an expert, until then save the money...

 Take a guess.. one prop is from Ebay and is made in China, the other is a Hobbyking version
The red prop is the Ebay version, it has a thinner blade, holds up quite well despite the price and the quality.

Powering your system with a UBEC

I use a UBEC to power the MultiWii pro, my two servos on the gimal and the reciever. I ordered two switchable UBECs off Ebay for $5, i am going to use the one UBEC to power the flight controller and the other to control the two gimbals on a separate battery.

There are different types of UBECS available but this one can be used and regulated between 5v and 6v and can be used with 2s up to 6s lipos. converts from 5.5volts to 26 volts into a constant voltage of either 5volts or 6 volts depending on the jumper setting. You could off coarse use your ESC to power your board, (if yours are still working in contrast to mine) but there is a chance that using the ESC´s you might draw too much power, making your multi-rotor fall out the sky if the flight controller powers off. Have  a look at this video that explains how a BEC works http://www.youtube.com/watch?v=hgXP4__GjSo

Firstly i found that most lipo batteries come with differnt connectors, JST, Dean, EC3, EC5, XT60 connectors and its quite a hassle converting from one to the other, i myself started using XT60 connectors and i bought a stack of XT60 connectors from China through Ebay they are pretty cheap and you will be amazed how often you need to use on of these connectors. I am no expert on lipo batteries but check out this guys page http://www.rchelicopterfun.com/rc-lipo-batteries.html he will tell you what there is to know on Lipos, chargers and the works. Read the safety precations on using lipo´s almost at the end of his article. he explains how not to puff your battery, but also what could happen if you are not cautious,.

Anyway i converted all my batteries with XT60 connectors, You can of coarse buy converters, they will convert from one to the other in a jiffy, but i am a true DIY man, so soldering is the thing i prefer to try and end up fucking it all up in due process. when soldering the connectors on and off take care not to short your battery in anyway, otherwise, puff and the thing grows to 4 times its size, gives you some awful smelling smoke and a fucked up battery (tried that too), lucky for me the thing never caught fire. So if you are newbie like me take great care and as i mentioned earlier read the advice posted in the link above.
What i initially learnt was to solder one cable at a time, cut the red, solder and then heatshrink it before moving on to the next wire, this way the chances of shorting are minimal.

I grabbed the UBEC and soldered a XT60 connector on the OUTPUT wire, remember to get the polarity right, red on +, black on - otherwise puff, another fucked up battery.

I cut  off the connector and striped the wire, found two red and two black wires

 Soldered the extra set of red wires together.
 soldered the two blacks together
Soldered the black/negative cable with the black/negative from the UBEC and the red/positive with the red/positive wire.
 Should look a bit like this, but with better soldering skills.
 Mounted the connector i had cut off again , had to find an extra connector to mount on the other cable.

 I have run out of heatshrink, this does a much neater job than duct tape, but this will do for now, notice that i now have two connectors available each giving five volts, you could make additional connectors if needed, i only need two, one for my reciever and one for the MWII flightcontroller.

 I connected the one connector into the Orange DSM2 through the BATT/BIND port, the middle rail has to be red/+ and the bottom black/- leaving the top signal rail empty.
On the last connector i took one of the signal wires from any of the 4 ESC´s and plugged it in to the empty slot next to the red/+ wire

Plugged the connector into the MultiWii pro board, in my case i used D5 which is motor 3, the red and black provide power to the MultiWii board and the green is the signal cable to the ESC from the MultiWii Pro board. Remember the inner rail is signal, middle is + and bottom is - on the Hobbyking MultiWii pro board.

A nifty tool for building multi-rotors

If you want to save yourself the hassle of  using all kinds of ways in keeping your wires stable when soldering, get yourself this nifty helping hand, you can order this at your local store or find on Ebay for about $10, from Asia, takes about 30 days but worth the wait.

A large part of my quadcopter was built trying to solder without a helping hand and how i regret, takes half the time to solder with this instrument, more precise and less fustration. Not that my soldering techniques are any good, but they seem to have upped a bit using this tool.