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Feb 06, 2009, 02:12 PM
Quad Crash Test Pilot
Mikro's Avatar
Quote:
Originally Posted by Georges41
Please give the details (where from) concerning the Blue Tooth connection you used to communicate with the Arduino.
It's pretty easy to attach a Bluetooth modem to your system. Just connect the serial TX (pin 1 of the Arduino) to the RX of the Bluetooth modem and RX (pin 0 of the Arduino) to the TX of the Bluetooth modem.

The 2 modem's I've used are:
http://www.sparkfun.com/commerce/pro...roducts_id=158 (with http://www.sparkfun.com/commerce/pro...roducts_id=145) and
http://www.parallax.com/Store/Access...%2cProductName

The documentation with the products pretty well describes how to setup a serial connection through Bluetooth on Windows.

Have fun!
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Feb 06, 2009, 07:04 PM
Registered User
Free2move
Bluetooth module are nice.
I tested two of them, receiving data at a distance of 350m (LOS in airfield). Connection start to be difficult, but I could have go further f I had more space that day...


Few description of my project (autopilote with IMU for RC glider) with pinout for this bluetooth module : (under construction)
Feb 06, 2009, 11:06 PM
Registered User
RCvertt's Avatar
Hey Paulrene and Mikro. I'm wondering if you guys have figured out the IMU stuff already but are just expecting too much from it?

Basing this off of my Walkera UFO-5 experience.
It drifts all over the place but slowly. With it's gyro gain turned up all the way it is most stable when hovering but it definately drifts. The accel is definately doing some work because when I tilt the craft it constantly increases the lower motors untill I tilt the craft level again.

With it's gyro turned all the way up it slightly wants to return to a hover on it's own after some forward flight but it still requires you to add some oposite input to return it to a drifting hover. With the gyro turned down it's more difficult to controll and it doesn't want to return to a hover on it's own at all. This causes you to chase the craft around with oposite inputs to try and get the thing to hover again.

So from my experience so far with the Walkera UfO-5 is that it is a more stable, yet still drifting, aircraft than it other wise would be if it was just gyro controlled only with no accelerometer.

My little AlienAir saucer that only has gyros basically acts like the UFO-5 does when the UFO-5 gyro gain controll is turned all the way down.

Not sure how the MikroCopter or UAVP compare to the UFO-5 though for stability.

I'm assuming you guys have flown other quads so you probably have a better idea of the stability a gyro and accel 6dof IMU should provide.

But if the Quaduino is a more stable, yet still slightly drifting, craft than it other wise would be with just gyro controll then it sounds like you have succeeded in my book.

Plan to make the UFO-5 gyro/accel board plug and play, like Paulrene is doing, with my Quaduino next so I can really compare the two.
Last edited by RCvertt; Feb 06, 2009 at 11:44 PM.
Feb 07, 2009, 01:16 AM
Quad Crash Test Pilot
Mikro's Avatar
Quote:
Originally Posted by RoyLB
Here is the link I promised to the complementary filter:
http://www.kerhuel.eu/wiki/index.php...ion_algorithms
Thanks for the info! Currently I've resorted to the "dumb guy" approach. for both gyro and accel noise filtering I simply do:
latestSensorData = (pastSensorData * 0.8) + (newSensorData * 0.2);

Then I just experiment with the PID gains till it fly's stable. Just tonight, I've rebuilt my frame to eliminate the vibration issues I'm having. I'm going back to playing with auto level again.

I've realized that maybe for the hardware I currently have I might have too high expectations for an auto level? I imagined that it would go straight up when lifting off and stay in a hands off hover indefinitely. With my current approach I can fly hands off for 10-25 seconds then need to manually adjust... but the adjustment is slight. I realized that my MK fly's similarly with the accels turned on. I probably could tune up the PID values on my MK but... maybe I've already implemented an auto level with my MikroQuad that is good enough already? I'll post another video and let you guys judge.
Feb 07, 2009, 01:29 AM
Quad Crash Test Pilot
Mikro's Avatar
Quote:
Originally Posted by vassilis
I am not using the same microcontroller but my project is quite similar and we seem to be facing the same issues, see http://vrhome.net/vassilis for more details. I am planning to release the source code once I get some time to clean it up.
Nice job! I originally was playing with a Stamp Basic, and was also looking at the Propeller... but then I found the Arduino! It's great you got yours off the ground in short order (judging form the timeframe of your blog entries).

I'd like to go back and play with a Kalman filter I got off the internet. Looks like you have one implemented for your quad. May I ask you some questions? First, here's my code for it at: http://code.google.com/p/mikroquad/s...c=svn112&r=112

I never quite understood what the three values meant that could be adjusted in the filter initialization for: Q Angle, Q Gyro and R Angle.

The sparse description I found was that Q Angle and Q Gyro was how much you trusted data from those sensors (I assume in radians)? Is that right, and what about R Angle?

Also I recently ordered this: http://www.adafruit.com/index.php?ma...roducts_id=123 as I've been running out of execution space with my Arduino. Since I've received it I'm planning to install it and experiment with the Kalman Filter again (I also think this is the reason why I haven't been able to execute my code under Arduino 0012, I noticed the binary was bigger so for sure I'd run out of execution space).
Feb 07, 2009, 01:45 AM
Quad Crash Test Pilot
Mikro's Avatar
Quote:
Originally Posted by RCvertt
Hope the 10amp ESCs didn't get too toasty for you.
Hah! I built up two frames, one for the 2410-09 / 10A Turnigy ESC's and the other for 20-22L / 18A Turnigy ESC's.

For the 2410-09/10A ESC frame I hid the ESC's inside the arms of the quad. I'm sure they got hot. I can't currently access it (which is probably bad) so I'm not totally sure. The motors feel slightly warm to the touch though. I do have a problem though as the rear of the quad keeps falling (I don't have this problem with my second frame). So it's a problem pointing to either the motor or ESC.

I'm curious, how do you guy's frames look? I try to hide all my wires, but my frames end up being a bit heavy (just bit the bullet and ordered some T-REX 600 CF tail booms to try). Do you guys have any suggestions for an aesthetically pleasing frame, but still light in weight?
Feb 07, 2009, 02:15 AM
Registered User
@Mikro

Many thanks for the answer. For what are you using the parallax version? When using the sparfun set is it possible to use a conventional Bluetooth PC on the other side?


Quote:
Originally Posted by Mikro
It's pretty easy to attach a Bluetooth modem to your system. Just connect the serial TX (pin 1 of the Arduino) to the RX of the Bluetooth modem and RX (pin 0 of the Arduino) to the TX of the Bluetooth modem.

The 2 modem's I've used are:
http://www.sparkfun.com/commerce/pro...roducts_id=158 (with http://www.sparkfun.com/commerce/pro...roducts_id=145) and
http://www.parallax.com/Store/Access...%2cProductName

The documentation with the products pretty well describes how to setup a serial connection through Bluetooth on Windows.

Have fun!
Feb 07, 2009, 09:18 AM
Registered User
Hi Frank,

I've just received all the bits I need to give the walkera gyro / acc board with a quaduino. Having searched around a number of RCGroups threads I couldn't find any details of the board's pinouts.

So, I decided to put my UFO-4 board back in an old X-UFO frame (partly to check if the Spektrum RX I've just wired into it works - it does), but also to see if I could deduce the pin-outs for the acc + gyros.

I've combined my findings with some other details (taken from a range of other's folks posts that I've found v. useful), and put it on a one-page summary (attached) - Would be keen to see if it makes sense to you. Also I'm not entirely sure if the Vref really is a Vref (when in use, that pins just sits at a rock-solid 2.77 volts)

Cheers

Pip.

Quote:
Originally Posted by frank48
@Mikro, PaulRene

I dont know if you guys have seen this vid using an arduino + acc to stabilize a camera. I guess the principal is the same for use on the quaduino. I realise they are using a servo but could the code be modified for use with the ESCs?

I think it may be helpful as the code used is published aswell

BTW - anyone had any success with the walkera ufo gyro/acc board??

http://maple.ces.kyutech.ac.jp/~jkob...ation%20Sensor

Cheers,
Frank
Feb 07, 2009, 09:38 AM
Tri-Quad-Hexa-Octo-copters!!
@Pip,
Very, very nice and useful Walkera UFO board summary.
Thanks for your time!
Cheers,
Jim
Feb 07, 2009, 11:10 AM
Registered User
@Jesolins

Thanks - hope it might be useful for someone out there (however as I said, must of the info came from regulars on RCGroups like yourself)

I've built myself a 50cm MK frame, with Towerpro w25a ESCs (not I2C modified yet, but prepared to do that if I go the MK route eventually), and Turnigy 2217 860kv BL motors, with EPP1245 Props, along with the good old Spektrum RX.

However, I really like the idea of using a Arduino (actually, I've got some freeduino clones instead), and using Mikro & PaulRene's code to build up a Quad myself in manageable stages, so I can really understand what's 'under the hood' as I go.

However, I'm at a bit of a crossroads - I'm tempted to do Quax's 'FET gate to PWM BL ESC Mod' with a couple of ATTiny13's to just see if I can get the thing in the air using the Walkera control board first (wouldn't take long to try).

Alternatively, I go straight to dismantle the Acc's and gyro's from the Walkera board, and try it them with my Arduino. Looking at recent posts from Paul - it sounded like he was on the verge of testing the Walkera gyro board himself a few weeks ago, which if it works would be a fantastic step to proving a lower cost, and software tweakable BL Quad. I'm just not sure I'm brave enough to try it first when I'm still so unfamiliar with the code.

So I'll think I'll try the Quax BL mod first, just taking the pulsed drive signal from the FETs' gates. One of my key questions on this, given I'm not doing the OMM opto mod is, will I need to put a dummy load on across the FET's (in place of the Brushed motors) in order to get the Walkera board to arm itself?

Perhaps the only way to find out is to try it (by disconnecting the brushed motors, and seeing if the board still arms), and if not finding what kind of minimum dummy load will work..

Will report back on progress - worst case I'll just get right onto trying the Walkera gyro+acc into the ADC ports of the Arduino, see what I get.

Final thing, just keen to get some general suggestions: the quadino-ng and Mikroquad - both look great to me. I wonder if there's anything to bear in mind as I chose which one to try first - e.g. which might be the best match for the kit I have. Is one easier to fly or set up perhaps?

Regards,

Pip
Feb 07, 2009, 11:44 AM
Went to mow a meadow
frank48's Avatar
Pip

Re your brushless conversion, I don't know if you saw (Jo)Hannes post, he has tried quax's mod and came to the conclusion the refresh rate was not fast enough to control a quad https://www.rcgroups.com/forums/show...&postcount=515

BTW I have a similar ref voltage (2.80v) on the third pin

Cheers,
Frank
Feb 07, 2009, 03:29 PM
Registered User
Frank,

Thanks - Ah, very interesting, I'd seen it, but wasn't sure if this was something to do with the specific 'converter+ESC' being used in that case. The following thread:

http://forum.xufo.net/bb/viewtopic.p...r=asc&start=30 that I followed from (Jo Hannes) site has a bit more info.

I'm not optimistic, it seems as if the introduction of the converter just add too much of a lag to the system. Shame, but never mind, back to plan B.

Thanks for the sanity check!

Pip
Feb 07, 2009, 04:05 PM
Finally got around to doing some more work on my Quaduino. Just updated my wiki/svn with all the new progress as well.

Wiki
SVN

The wiki has a few articles with basic info and two pictures on my projectso far. If anyone would like elaboration please ask and I'll put up more details.

On the software side of things I only just got my Sparkfun 5DOF so I haven't been able to do anything of much use. The Processing application that was asked about before is up on subversion however there may be a few lines that need to change as I was only using it with one gyro to test.

I do have two questions, I'm not too familiar with the RC side of things.
  1. For my ESCs I have Plush 12As, the three wires that connect to the motor - what is the difference between the three? There seems to be no discernable markings on them.
  2. Also, the pins that connect to the receiver (red/black/white) what are the wirings on them? I'd assume PWR/GND/SIGNAL-PWM... I'll need to interface these with the Arduino.

My MediaWiki installation seems to be having issues with upoading images. If you see a 500 error, that's why. I'll get around to fixing it in a while.
Feb 07, 2009, 04:12 PM
Went to mow a meadow
frank48's Avatar
Quote:
Originally Posted by minusthetiger
  1. For my ESCs I have Plush 12As, the three wires that connect to the motor - what is the difference between the three? There seems to be no discernable markings on them.
  2. Also, the pins that connect to the receiver (red/black/white) what are the wirings on them? I'd assume PWR/GND/SIGNAL-PWM... I'll need to interface these with the Arduino.
1. You can connect these any which way to the motors, they are 3 phase connections. If the motor rotates the wrong way just switch 2 of the wires over.

2 Yep, thats ok

Cheers,
Frank
Feb 07, 2009, 05:37 PM
Registered User
Fredjikrang's Avatar
Just curious, but are you guys flying with the brake on or off on your speed controllers?


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