here's the thing. they say, dont go below 3v per cell static. that will damage it. however, your voltage drops under load, so they say dont go below 2.5v per cell under load. i guess i will be a bit more conservative and call it 8v per cell for the second LED. i am usre it will be fine at 9v and 8v.
Thanks,
-Clam

Got the new pcb.... time to start the soldering iron!

hey PuCkStAr,

I tried sending you a private mail, but doesn't work.....

Anyway, I passed on your e-mail to Gernot.

Thanks Tve,
I'm not too sure why PM's aren't working. My account seems to be somewhat restricted with regards to options and settings.
PuCkStAr

is it post related? ask rcadmin. if anyone can help it's him.
Cheers,
-Clam

Hope you guys don't mind me posting all these images

Not quite done yet, but it is going together nicely. I'll finish it tomorrow. One stupid mistake so far.... Somehow I managed to delete the mounting holes before I sent it off. It is going to be real fun trying to mount this thing....

Note that the yaw gyro/acceleromter pair is under the magnetometer... so you can't see it.

This is what I see....

OK ..... It's done. With fixed resistors the closest I could get was 9.02V and 7.93V
To get it perfect would have meant using preset pots, which I wasn't keen on, because of the possibility of accidental adjustment due to vibration or crash.
Shouldn't take long to get to the US from here.

Cheers ADI

Nice PCBs Tve. Any idea when she'll be flying ?

Cheers ADI

I hope very soon.... 2 weeks?

I haven't tested anything on the board yet ... so that might be jumping the gun
I will know more tonight after I get home...

puckstar,
scroll up to the top of the page. under where it says electrics, planes, helicopters, boats etc and find the tab that says settings. click on it. scroll down until you find the mox that says "allow others to send me private messages" and check it.

Hey guys... thought i might as well introduce myself a bit seem as my forum settings problem has sidetracked this thread.
I am in the fourth and final year of my degree doing Mechatronics Engineering in Australia.... and believe it or not.... i am building a DF for my final year project..................with my uni partner (Aussie Mechatronics Guy), WOW small world ay
I have been following all of your progress for quite some time now, but have somewhat been lagging the constantly growing size of this thread, as you can see now, i have finally caught up with you all.
im sure you'll see me around a little in the future making posts
PuCkStAr

Re: Spaceclam....
yes i have had that "allow other members to send you PM" box ticked since the day i registered with RCUniverse, so think i'll have to follow the matter up with Admin.
Thanks anyways

Hi hi, I'm also building the DF for my final year project in degree of mechatronics engineering....

hi all
over the past few days/weeks ive been working my way through this entire thread, i havnt read everything proply yet, started doing big jumps because theres just so much! but i will get through it. im hooked, and i wanna build a df!! cool hey. im currently in 3rd year electronic engineering in south africa (now you really do have people from all around the world) and im looking into building it next year for my final year design project, and if not for university i just want to build 1 for myself because they look really cool. so i want to get all the info and plans and thoughts done early so next year i can jump right into it without reading 85 pages of forum when i should be building my design...
im fairly clued up on programming a microcontroller (atmel avr's) the chip we've been using is the ATmega8515., and im in the process of studying PID control loops and all that stuff. one thing im not super jacked up on is RC stuff. ive had my share of radio controlled cars, ive built a couple, never more than 2 channel, and theyve all worked but i dont know exactly whats going on. could one of you 'experts' give a breakdown or flow diagram of what exactly happens from the transmitter until the signal reaches the micro.. from what i gather, you have the receiver (4 channel minimum) which basically feeds right into the chip and the chip does all the rest (assuming the chip has A/D capabilities), or are there some steps in between. has anyone drawn a block diagram of the entire system? (with nested blocks showing feedback control etc) sorry if this has all been discussed but i havnt read through everything yet, suppose i should do that before piping up here but you know how us engineers are, anxious to get ahead.
anyway its been great learning all i have so far and im sure il be in touch alot more in the future.
thanks for all the knowledge you guys have shared.
cheers

Hi guys, I'm back from my holidays. Wow, New York is a impressive city but can also be very stressfull. Now I would need another 2 weeks to rest from my holidays! but I have to go back to work very soon.[]

kwaiweng: Your videos are nice; It doesn't seem that you have stability problems; but this is what I can tell you:

- You should be able to do a complete z turn like I show in my video. The down movement in that video is not because of the algorithm. It's because of my finger (I found it difficult to move my thumb left-right without moving up-down) I have improved on that since them and now I can do it maintaining the same alttitude and without touching the right stick.
In other words, flying the DF needs not only a good algorithm but some finger-practice too. You may think that I'm a RC master but I'm not, I only have a glow trainer, a IFO slowflyer and I had never flown any helicopter of any kind before I made my DF.

- What you call your problem [1] is in fact done INTENTIONALLY in my algorithm because the stick movement is integrated as well as gyro output. Normally, with a small integration constant you wouldn't even be conscious of it, but if you don't like it at all, just remove the stick term from the integration equation; however it provides the necessary correction for the drift that the gyros have during the flight. Otherwise you would have to correct it with the trims and soon you would run out of trim control and you would have to land and take new references again.

- I may be wrong, but I think that 600g is too much for a single 1500mah Li-Po battery. Are you sure that total current is under rated CONTINUOUS discharge? Otherwise your battery won't last long.

-I also agree with the motor heating effect that Spaceclam describes.When small ICS-100 motors heat up, I loose a lot of thrust because hot windings and brushes means higher motor resistance (less power output). I normally allow them to cool down a couple of minutes and I'm able to take off again at full power without recharging the battery. I also wrapped the motors with a U shaped 0,2mm thick aluminium foil (large area and little weight).

Nice to read from all of you again, guys.

a lot of people see to do this for a final project for engineering. i was in personal contact with two university guys for a while too, so this makes about what 6 or 7 that i have come across.

i have also found that flying rc helis is actually a lot easier than flying DFs. the first time i got on an RC helicopter i had flown this many times, and i just got on the controls and flew it around without my instructor taking over on the biuddy box at all. DFs are fun that way.

i figured out that a lot of the power loss i was experiancing was becuase of vibration. not all of the power loss, but a significant bit. the motors are definatly worn a bit though. i talked to feigao about the motor things, and he said they warantee their motor, but he did not speak enough english to understand the words "4 rotor helicopter" so the thought i was trying to fly a 2.25 lb plane around with only 44watts input power, no matter how many times i told him otherwise[:@]

i think part of the problem i am experiancing is that i dont think my shafts heat treated correctly, becuase they still bend and stay bent, and they are made out of drill rod. the next time i start having problems i will anneal them and try again.

some awsome news guys.
i figured out what the problem is. all of my motors were lagging a bit from vibration, but only by about 50-100 rpm.
the real problem was my starboard motor. it runs about 550 rpm slower than the rest. i have swapped speed controls, swapped motors, swapped gearboxes, and it's definatly the motor. it was running 550 rpm slower, and at full throttle while the other motors were not. so, when my motor was lagging, i trimmed it to stay neutral. the motor could not go any faster, so what my trim did was slow down the other motor about 500 rpm to match it. then, this caused a torque effect. so when i gave it rudder, it slowed down the other motor to compensate. it was a chain reaction. this does not fix my gyro problem, but it could make this a lot easier to fly. we'll see.

Hi ADI, may I know how much weight is your DF and how much current it draw when hovering (sorry if this has been mentioned before as I'm lazy to search the whole thread again)? Mine one is not exactly 600g but it's something between 550g - 600g. I feel like it's a bit heavy and the power consumption is too much. My flight time is less than 5 minutes. I'm using a 20C Li-Po battery, so I assume that it still can handle the current (I never measure it before). but anyway my battery will become warm after flying for sometime but my motor is still considered cool...

wow. your guys's DFs are really light. it must have something to do with my half pound of electronics crap...

kwaiweng, as long as your battery is just warm (not hot) your battery is fine. some of the higher discharge, low impedance ones will get hot and still be fine, and 20c is pretty high discharge. you are fine

But I'm not happy with the flight time. Maybe I should get a long wire and fly my DF tethered. I just wonder how the original DF only draw about 7 amp when hovering. the weight for the original DF is about 480g. My Df just weight aobut 100g more than the original DF, but the current needed by my DF is much much more than the original DF...

ADI,can you tell me more about your yaw algorithm.In my opinion, I don't think yaw algorithm is the same as pitch and roll .we want control pich and roll angle at 0 degree (hoziroltal) but yaw angle can be any angle.
I have problem with intergrating yaw gyro ,it's seem to be have large error over long time(10 s).
Any idea to solve it?.I use ENC-03 Murata Gyro
Regards,

Hi Anthrax,

Believe me ... it is the same algorithm. Danvel, who came up with the algorithm will confirm this.
The 3 gyros and TX sticks are sampled just before takeoff. Their individual readings are then stored in memory and considered as 0 degrees in all 3 axis of pitch, roll and yaw.
You must understand that 0 degrees is nothing more than a 'no gyro activity' signal, ie gyros' stationary state. So the 3 gyro samples that are taken are just the voltage levels produced when DF is stationary.
Your TX sticks do over ride the gyros and Df gets shifted in the yaw axis, if you so desire, but eventually balances back to some stationary postion pointed in whatever direction you have chosen.
So if you remember that so called '0 degrees' is same as 'centre gyro' ie. 'stationary'.

Cheers ADI

PS: This algorithm is not actually dealing with any absolute angles relative to the ground below.
If it senses a (+) gyro signal in a particular axis, it will drive the appropriate motors untill it receives a gyro signal that reverses in the opposite direction through gyro centre, continuing untill a (-) signal of same proportion as original (+) signal is received. Then waits for this (-) signal to come back to centre again. It then considers that it must have corrected for the error and brought DF back to our sample reference position. It is in fact performing this task with it's eyes closed, in reality. It relies on the pilot to make any small adjustments if it doesn't perform this task perfectly.

Cheers ADI

In the other words, we can say that we are performing PID control on the angular velocity, not the absolute angle. So our P term will be the reading from gyro, which is the angular velocity. I term is the integration of the gyro reading, which is the angle. and D term is the derrivation of the gyro output which is the angular acceleration. So the set point for our PID control would be angular velocity = 0. I think that's why my problem 1 exist. It's because if I move my stick forward, then the DF will tilt forward. then I center the stick and the DF will remain tilting forward because it will try to match the set point and refuse to level back....Danvel, is my explanation correct??


p/s : adding the D term which is the angular acceleration will help much on the algorithm. To minimize the noise, I sample the gyro reading 100 times and I use the average value.

OK, kwaiweng. Now you got the idea. Our control variable here is angular velocity.
But I insist; due to the small integration constant it takes a large and long (in time) stick movement for the reference "level" to become tilted more than a fraction of degree. If you make a quick stick movement and then return to center, the DF should level back to about the same "horizontal" plane than before. If not; maybe your integration constant is too large. HINT:
I integrate every 1/50 sec or 20ms. Maybe you're doing this calculation more often? In that case you should reduce the constant accordingly.