First Quadcopter build started - video diary

dtrewren

dtrewren

Well-Known Member
Evening people,

No video 'this time' but I have acquired a new module that I am very excited about (must get out more) !

Got my hands on a XL-MaxSonar EZ4 MB1240 module - this little module is very cool in my opinion. It has approximately a seven
meter range +/- 1cm ... well here is the spec :
  • Resolution of 1 cm
  • 10Hz reading rate
  • 42kHz Ultrasonic sensor measures distance to objects
  • Read from all 3 sensor outputs: Analog Voltage, Serial, Pulse Width
  • Virtually no dead zone, objects closer than 20 cm range as 20 cm
  • Low 3.4mA average current requirement
  • Real-time automatic calibration (voltage, humidity, ambient noise)
  • Firmware filtering for better noise tolerance and clutter rejection
  • Narrowest beam of the XL-MaxSonar-EZ products
  • Highest noise tolerance of the XL-MaxSonar-EZ products
  • Great for large target applications
  • Maximum range of 765 cm (300 inches)
  • Hardware gain of 250
  • Short range, narrow detection zone for small targets
The Arducoper firmware takes 60% of the maximum range so ~4.5m as a switch point above which the barometric pressure
sensor is used and below which the MaxSonar is used.

After my fight with wind over the weekend I thought I would try and stabilize my altitude hold performance by integrating
this module which also gets used for auto landing.

I will post up a video of performance once I get the module fitted - off to Paris for a few days to party but back soon :)

Cheers,

Dave


Now that is a cute module .....
MB1240.jpg
 
dtrewren

dtrewren

Well-Known Member
Morning Quad people,

I can report back the ground sensing Sonar works REALLY well :)

Mounted the module in a little box and mounted the box to the rear of the Quad - only space I had left. Three connections
to the Arducopter A0 port. As recommended I also fitted a simple power supply filter consisting of a 10ohm (ish) resister
and a 100uF capacitor.

I then enabled the Sonar input from within the flight planner. Then attached to the Arducopter using the terminal window.
Once connected entered test mode by typing 'test' and the Sonar logging by typing 'sonar'. Data immediately streamed out
indicating the minimum distance of 20cm. I used a meter rule from my workshop floor and the data stream indicated 100cm
absolutely bang on - well the specification is +/-1cm.

Weather is a bit rubbish here but had to try a quick test flight. Entering altitude hold at about 2m the Quad was very
stable in terms of altitude ! Very cool the way it hugs the ground and as you manoeuvre over obstacles the Quad faithfully
maintains the altitude, rising and falling in height :)

Right, off to Paris ....

Any question please fire away,

Cheers,

Dave


Sonar fitted.jpg
 
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H

Hugh Hemington

Well-Known Member
I've really only heard of interference related to things that radiate a lot of power, like the ESCs or main battery cable (or FPV tx). It's pretty common to build FPV "modules" with an OSD and camera switch in close proximity with no issues.
 
H

Hugh Hemington

Well-Known Member
I would be interested to know how your sonar unit does at the higher limit of its range. Will it hover and hold at 6 meters? And what mode do you use? If altitude hold, is APM smart enough to cut out the sonar and use only baro/GPS above a certain point?
 
dtrewren

dtrewren

Well-Known Member
Afternoon Hugh,

I don't seem to be suffering any interference problem at all at the moment. All the 12V gear is running from a dedicated UBEC
and looking on my scope the supply looks nice and clean. As I mentioned I also fitted a simple single pole RC filter to the
supply input to the Sonar although the supply look clean to start with.

My understanding is the Arducopter firmware sets the maximum usable altitude of the Sonar at 60% of the manufacture
specified maximum range so in my case (60/100)*7.6 ~ 4.5m

Below the 4.5m imposed range I believe the Arducopter uses the sonar and above which it uses the barometric sensor. I
will do some flight tests once I have recovered from Paris and it has stopped raining :) Will also see about getting Sonar
sensor telemetry data.

I wanted to fly some relatively low level video and so wanted the Quad to ground hug as opposed to ditch on the first upward
ground undulation !

Cheers & happy flying,

Dave
 
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dtrewren

dtrewren

Well-Known Member
Evening all,

I have such a fun hour or so this afternoon flying and testing out the Quad !

Hugh in answer to your questions regarding the Sonar altitude hold .... it works really well. The Arducopter firmware appears
to switch between the Sonar and the barometric sensor automatically and when flying you don't really notice. The only thing
I have noticed is as you bank steeply using the Sonar obviously the distance measured to the ground will increase as the sensor
is no longer pointing straight down ..... Pythagoras and all that :) So the upshot is as you bank you tend to loose some height
and then you re-grain the height as you level off - measurement to the ground as opposed to the absolute measurement
provided be the baro.

I still have a small video camera stability issue. The gimbal is working perfectly but the camera is bouncing I think due to the
weight of the camera/gimbal causing the frame to flex. I reinforced the frame with an aluminium strip but I think this has
pulled away - I only used double sided tape. So I think I need to re-attach the plate with contact adhesive.

Here are bits of the two videos I shot (not terribly interesting) one from the Boscam HD08 camera and one from the Sony
FPV camera with OSD recorded on the Quad using the little SD video recorder.

Cheers,

Dave


Main Boscam HD08 camera on the Gimbal :



Sony FPV camera & OSD recorded on the Quad :

 
H

Hugh Hemington

Well-Known Member
I'll look into adding SONAR. My Parrot has it, but the controller probably can't apply the return data fast enough, so it isn't worth much on that platform.
 
dtrewren

dtrewren

Well-Known Member
Morning GJH105775,

Yes you are correct the HUD information is introduced onto the video link on the Quad using a telemetry video
overlay module. If you pop back to the previous page of this thread about two thirds down the page there is
a bunch on information (video & basic schematic) showing the set up I used.

I used the MinimOSD module :
https://code.google.com/p/arducam-osd/wiki/minimosd

In a nutshell :
The module inputs telemetry information from (in my case) the Ardupilot flight controller via a dedicated
serial link. A microprocessor on the OSD module processes the telemetry information and configures a
video overlay device. Composite video from the camera inputs & outputs the OSD module having the telemetry
information superimposed onto the camera video stream.

I went one small step further and added a dedicated SD video recorder so I could grab clean video on the quad
rather than broken up video on the ground.

A nice feature of the MinimOSD is you can download a piece of set up PC software and configure the module
to display a huge range of telemetry information !
https://code.google.com/p/minimosd-extra/

OR
https://code.google.com/p/arducam-osd/wiki/OSD_Config_Tool

Any question fire away :)

Cheers,

Dave
 
GJH105775

GJH105775

Off and on
Moderator
dtrewren said:
Evening all,

I have such a fun hour or so this afternoon flying and testing out the Quad !

Hugh in answer to your questions regarding the Sonar altitude hold .... it works really well. The Arducopter firmware appears
to switch between the Sonar and the barometric sensor automatically and when flying you don't really notice. The only thing
I have noticed is as you bank steeply using the Sonar obviously the distance measured to the ground will increase as the sensor
is no longer pointing straight down ..... Pythagoras and all that :) So the upshot is as you bank you tend to loose some height
and then you re-grain the height as you level off - measurement to the ground as opposed to the absolute measurement
provided be the baro.

I still have a small video camera stability issue. The gimbal is working perfectly but the camera is bouncing I think due to the
weight of the camera/gimbal causing the frame to flex. I reinforced the frame with an aluminium strip but I think this has
pulled away - I only used double sided tape. So I think I need to re-attach the plate with contact adhesive.

Here are bits of the two videos I shot (not terribly interesting) one from the Boscam HD08 camera and one from the Sony
FPV camera with OSD recorded on the Quad using the little SD video recorder.

Cheers,

Dave


Main Boscam HD08 camera on the Gimbal :



Sony FPV camera & OSD recorded on the Quad :

Click to expand...

Can't believe how much of a difference self levelling gimbals make. I synced the two videos together, played them and was supprised.
 
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