The Sweptback WiiCopter

[copterrichie]

I upgraded my Sweptback copter from the Flymentor to the MultiWiiCopter version 1.7. It flies so well with this version till I am very reluctant to change anything at this point. It is using an unmodified Wii itg3205 clone and a MMA7455 Accelerometer.

http://www.youtube.com/watch?v=ELOChv2Drxo






My next stage is to integrate FPV

[copterrichie]

Here is another video of the Sweptback titled: Invasion of Bird land.

After watching this video, I upgraded the tail motors from 1100KV to 1450KV and increased the Yaw Rate.

http://www.youtube.com/watch?v=1AFDdbES8xc

[copterrichie]

Here is the Sweptback after the tail motors were up graded. Hope you will enjoy it.

Thanks.

http://www.youtube.com/watch?v=KyAI4NLfPMI

[quax]

awesome

Can you give me some more construction information?

Is the MMA7455 with it's +/- 127 solution satisfying?

Did you ever recalibrate the MMA7455?

[copterrichie]

awesome

Can you give me some more construction information?

Is the MMA7455 with it's +/- 127 solution satisfying?

Did you ever recalibrate the MMA7455?

Well, all of this is very subjective but I find the MMA7455 performance Amazingly accurate on my copters. With this said, the only other Accelerometer I have used is the BMA020 and there is no comparison. Once the MMA7455 is calibrated, I have never had to recalibrate them and there is absolutely no drift. Zero is Zero. I am still using version 1.7 because for some unknown reason, I can not get it to work well with version 1.8. The code for version 1.7 is very simple, nothing special at all.

Code: Select all

// Developmental code for the MMA7455
#if defined(MMA7455)
static int8_t rawADC_MMA7455[6];

void i2c_ACC_init () {
  delay(10);
  i2c_rep_start(0x3A);    // I2C write direction
  i2c_write(0x16);        // Mode Control
  i2c_write(0x25);      // Set Sensitity Value @ 2g
  //i2c_write(0x21);      // Set Sensitity Value @ 8g
  
  
  acc_1G = 64;
  acc_25deg = 27; // = acc_1G * sin(25 deg)
  accPresent = 1;
}

void i2c_ACC_getADC () {
  
  TWBR = ((16000000L / 400000L) - 16) / 2;
  
  i2c_rep_start(0x3A);     // I2C write direction
  i2c_write(0x00);          //Registry to start reading from.
  i2c_rep_start(0x3B);  // I2C read direction => 1
  
  for(uint8_t i = 0; i < 5; i++) {
    rawADC_MMA7455[i]= i2c_readAck();}
    rawADC_MMA7455[5]= i2c_readNak();

    accADC[PITCH] = -((rawADC_MMA7455[1]<<8) | rawADC_MMA7455[0]);
    accADC[ROLL]  =  ((rawADC_MMA7455[3]<<8) | rawADC_MMA7455[2]);
    accADC[YAW]   = -((rawADC_MMA7455[5]<<8) | rawADC_MMA7455[4]);
 }
 #endif

[copterrichie]

P.S. This is just my opinion but because of the resolution of the MMA7455 makes it LESS susceptive to vibration.

[copterrichie]

Here is another one of my practice session. Hoping the build up the courage to venture out over the water soon.


http://www.youtube.com/watch?v=l5glXutAkAU

[copterrichie]

Maiden FPV Flight coming Soon.

[zarkon]

what the frame made off? aluminium?

[copterrichie]

what the frame made off? aluminium?

Yes 1" aluminum, wall thickness .020

[zarkon]

what the frame made off? aluminium?

Yes 1" aluminum, wall thickness .020

ok thanks, I never a saw an aluminium like that here, most of them are solid steel

[copterrichie]

Here is a short video of my latest FPV equipment testing. The Sony bloogies Requires lots of light because of the CMOS lens, I shot this early in the morning about 6:30 am. By no means have we arrived at our final configuration and there is still much to be done. The flight was short and done with LOS. I discovered some problems with the OSD and the Vupoint DV Recorder is no good for this application. Just as well, we get what we pay for, I picked this one up for $17 bucks plus shipping. Anyway, just figured I would share.

http://www.youtube.com/watch?v=bxx6eX7cEVE

[Noctaro]

hey,
nice testings!
do you have a seperate lipo for fpv gear? this should solve the problems with the stripes. I tried many kinds of cleaning the signal from flight lipo, without succsess. Tried ferrit cores, elkos,...
But only a small 3s lipo could solve my problem. Keep up the nice work!

greetz Noc

[copterrichie]

thank you Noc, yes I have also tried a separate battery but that is not the problem. It was the OSD, the lines are visible in this ground test video also. At the time, I thought it was my WiFi router. I have built a new OSD and the lines are gone on Ground testing, I have not aerial tested it yet.

http://www.youtube.com/watch?v=FBaWsjBz5IA

[copterrichie]

This is a morning test video to determine vibration levels and how level I can maintain flight using the updated MWC 2.1 firmware.

https://vimeo.com/50988916

[copterrichie]

The mission of this copter is to carry a camera payload to a predetermined altitude and location, hover about, then return home. So none of my video will be about proving how well this design can handle 3D or Sport Flying. First rounds of testings looks very promising, nice and stable in mild winds, gust about 10-14mph. In this video, only the Gyro and Accelerometer are used. Next rounds of testing will include GPS and Altitude holding.

http://youtu.be/t-cZpvOf2cw

[kataventos]

Subscribed

[copterrichie]

Took the Sweptback II out to the park for additional flight testing, have not flown it since the upgrade to MWC 2.2. Wanted to test the Gyro Scale factor for the L3G4200D mentioned here: viewtopic.php?f=8&t=3520



I would say, Kudos and Job Well done!!!

[NikTheGreek]

How many projects are you running at the same time ?

[copterrichie]

How many projects are you running at the same time ?

Actually, I have lost count but it is just how I do things. When one project becomes stagnant or I have issues with it, I set it aside until the answer comes. many of the projects are so unique, I can't ask others for assistance. So I just have to work things out for myself. The answer to this one came in the form of the Gyro Scaling, made a huge difference in the flight quality.

[Freelancer]

copterrichie:

I'm working with a MMA7455 accelerometer right now. Could you tell me anything about how to find yaw data using it? Thanks.

[copterrichie]

copterrichie:

I'm working with a MMA7455 accelerometer right now. Could you tell me anything about how to find yaw data using it? Thanks.

No ACC has any control over the YAW axis, the Z axis of an ACC is up and down. With the MultiWii, Yaw is control with the Gyro only.