First Quadcopter build started - video diary

[dtrewren]

Yep, we have blade servers at work and they need crazy cooling !

I think we used these little 1 inch fans a few years ago sat on top of the older generations of Xilinx FPGA for
cooling. The ones we use now (Kintex 7) don't need external cooling and so the fans were obsolete - but
perfect for a Quad cooling project

Cheers,

Dave

 

[dtrewren]

Hugh,

Question for you .....

Do you have CW & CCW prop hubs for your x3108s motors - I am having a hard time
finding a supplier of CCW hubs in the UK

Cheers,

Dave

 

[Hugh Hemington]

My SunnySky motors came with Nyloc nuts (nuts with nylon inserts) so they don't get loose in flight. I'd get a set of those and not sweat it. You'll also want some kind of ratchet and socket. My nylocs are 10mm and I use a "palm ratchet" -- a flat round knurled-edge socket holder. You don't need the leverage from a handle ratchet to tighten the prop nuts.

 

[dtrewren]

Hi Hugh,

Ah ok, I have gone for it and ordered up some motors to give me a bit of power headroom. Looking at the image of 'the bits' it looks like the nuts are possibly Nylocs. I have a load of Nylocs in the workshop so will pop some on should the supplied nuts be a standard type.

Yep, as you say you don't want to over tighten the prop bolts the web covered in cases where guys have over tightened and stripped the thread.

Cheers for the info,

Dave

 

[dtrewren]

Hello & good evening !

I have not forgotten the forum ...... been working on the Quad and have now got things to report.

First off, one reason for the delay is that I made a school boy error ! Even though I do electronics for a living managed to reverse
polarity connect the battery ...... too late and not paying attention. Anyway the upshot was it blew up the power module being
quite cheap I decided to buy a new one locally but it turned into a bit of an ebay nightmare and had to wait two weeks obviously
not being able to fly or test in that time. So don't reverse polarity connect because the power module will die.

New power module now fitted and working well.

Having looked around and taking on-board Hugh's recommendations I invested in a set of SunnySky X3108S 720kv motors. They
are really nice, very smooth and quiet with lots of power. I have fitted them with carbon fiber 11 x 4.7 props.

I have also been experimenting with different batteries and have had a great afternoon test flying with the following :

- Turnigy Nano-Tech 4S 5000mAh
- Turnigy Nano-Tech 3S 6000mAh

Both batteries have the same form factor and fit the quad frame perfectly achieving spot on CG with the gimbal and camera up front.
I have also fitted a 12V UBEC to supply the Boscam FPV camera & gimbal hardware.

The first thing I noted with the 4S 5000mAh battery fitted was some vibration but this was easily cured but reducing the P gain on pitch
and roll from 1.536 to 1.335. This is not surprising as the higher voltage will make the motors more responsive and there was just a touch
too much gain in the loop.

Both batteries have been cycled from new twice and produce almost exactly the same flight time. Before fitting the new motors and
with my original 3300mAh standard Turnigy battery I was getting about 7 minutes flight time until the alarm went off.

With the new motors, props and either battery I am getting about 13.5 minutes flight time

I would say the 4S battery makes the quad more responsive when maneuvering but both are solid when loitering.

Looking at the logs with the 4S 5000mAh battery fitted the voltage current looks like :

- Initial take off with fresh battery : ~15.7V @ ~17.2A ~4.3A/motor Loitering
- At the point the alarm went off : ~12.2V @ ~23.5A ~5.8A/motor Loitering

The motors were cool on landing and the fan cooled Q-Brain just a little warm.

So overall a really nice improvement and must more usable flying time.

Any questions please fire away.

Cheers,

Dave

 

[Hugh Hemington]

Battery connectors are polarized, so how did you manage to connect it backwards?
I'm glad you like the SunnySky motors. If I have the scratch, I'll never buy anything else.

I remember when I first changed the battery connector and made the mistake of cutting both leads off the old connectors... yeah, you know where I'm going with that!

 

[dtrewren]

Hi Hugh,

You are completely correct the battery connectors are polarized ..... and should be fool proof.

Turnigy batteries are supplied with a bullet style connector which as you say is polarity sensitive. I have been using a bullet to XT60
adapter to connect to the APM power module rather than hacking the battery connector.

I had been running a flight test of around ten minutes and then landed to switch batteries. The cable & connector were a little warm
due to the load. I think because the adapter was warm the plastic of the bullet connector was very flexible. Although it was not
possible to plug male/male together it was possible to make momentary contact and that was enough to cook the power module.

I have now marked each correct respective side of the connector with a black line and make a mental note to stop and think before
making a connection !

Cheers,

Dave

 

[dtrewren]

Good afternoon guys,

I have been having fun flying and testing this afternoon. I am very pleased with the Quad now, it is flying really well - very
stable and responsive with a nice 14 minute flight time.

This afternoon I have been working on improving the HD camera stabilization. The Boscam HD camera is mounted on a
two axis active gimbal which I have tweaked to get nice smooth performance. The weak point was the fact that the gimbal
itself is mounted hanging off the front of the Quad. The Quad frame base plate is essentially made from fibreglass or
possibly FR4. This mounting is quite flexible and I think was oscillating so I have re-enforced with a 30mm wide strip
of aluminium. I also added some foam to the gimbal to stop the lower plate bouncing on the anti vibration supports.
These two actions completely cured the jello and frame bounce issues I was seeing.

I have produced a video (crowd goes wild) showing an inset video of the Quad being thrown around by yours truly and
the main frame which is the output from the Boscam gimbal stabilized camera.

Although some movement of the main camera is inevitable due to the gimbal being a PID feedback mechanism and
not a time machine the results are very nice and stable.

Comment always very welcome !

Cheers,

Dave

Little edit, here is a full size of the Quad from the ground

 

[dtrewren]

Evening all,

Today I got my hands on a 5.8GHz FPV receiver and screen. The little 5 inch unit also operates as a PVR and
has a 32Gb micro SD in the side allowing recording as well as viewing. The screen fits to a bracket which then
fits to a lightweight carbon fibre bracket that mounts onto the carry handle of the Turnigy 9x Transmitter.

I do have some goggles (without an integrated Rx) but not quite confident enough to use them yet. The little
screen also has a video out connection which will allow me to feed the goggles from the screen receiver
in the future.

The screen is very nicely made but at the same time light at only 200g - it doesn't come with a sun shield
so that is something I will have to fabricate.

Receives signal from the Boscam TR1 camera perfectly - I will probably upgrade the antennas at some
point but initially will be keeping things close range.

Hope you like ..... ?

Cheers,

Dave

 

[Hugh Hemington]

Good setup. Are you still able to use a neck strap to relieve the weight? Seems like you may need to extend and move the attachment point to the base of the antenna for this rig.
Have you noticed any range loss from having an RF noise emitter so close to the radio antenna? It won't be long before you go to goggles and hand that screen to spectators. Then you'll probably want a separate receiver so you aren't tethered to those watching the screen.

 

[dtrewren]

Hi Hugh,

Sorry for the delay in responding .......

Yes the neckstrap works very well, in fact better than before the monitor was fitted. I replaced the dry cell battery box with a 2200mAh recharge but this had the effect of making the Tx bottom heavy - the new monitor counteracts the weight of the battery and the Tx has now much better balance.

Didn't really notice any loss of range caused by the radio antenn. I am about to replace the stock monitor antenna with a clover leaf style antenna which will be positioned much further away from the Tx antenna.

The main issue at the moment is the Boscam TR1 camera seems to produce quite a dark output and its AGC appears to expose the sky perfectly at the expense of the ground. There is no way of changing the camera gain so I think the only solution is to point the camera downward slightly so as to include less sky in the frame and hopefully better expose the ground.

Also need to build a simple sun shield for the monitor ....

So many projects and so little time

Cheers,

Dave

 

[Hugh Hemington]

It's odd the TR1 darkens the ground. I've seen many videos from them that look good. Maybe there is an adjustment?

That doesn't look like captured FPV footage, but I can't imagine the realtime video is very different from what gets recorded.

 

[Hugh Hemington]

Is this what you're experiencing?

Apparently this guy tilted it down a little. I think I'd look for a different camera.

 

[dtrewren]

Hello Hugh et al,

Yes the FPV transmitted output appears to have poor dynamic range. I suspect the HD recorded data has a similar issue but
it is less noticeable due to wider dynamic range. It's a bit difficult to say for sure because there is very little information available.

I have looked into the possibility of adjusting the camera settings but as far as I can tell they are factory fixed.

If I shoot (using FPV) a scene with say ~30% sky the below horizon detail is very badly underexposed. Shielding the camera lens with ones hand immediately causes the AGC to increase the gain and the below horizon detail becomes much more acceptable. This is very much less apparent when viewing the data stored on the MicroSD card. The only solution seems to be to point the camera down to avoid as much bright sky as possible.

However, this is not the main issue I have with using the camera for FPV. I very much want to integrate the OSD video overlay module I have. Unfortunately on inspection the TR1 design is heavily integrated and does not have an internal discrete RF power module. I 'could' find the composite video input to the RF PA and break it out but this would mean butchering the camera to some extent rendering it unsellable. So I have decided to move on and get a separate FPV camera (Sony HAD 600 tvl) and a discrete 200mW RF PA module. Now I can break the video out easily and integrate with both the OSD module and Mavlink radio telemetry module.

Here is a video showing the Sony camera I have gone for :

A project is like a living thing - it evolves .....

Dave

 

[dtrewren]

Good evening everyone,

I have been having big fun modifying my Quad and adding new & interesting things

First thing I have removed the Boscam TR1 integrated camera & transmitter. I have spent some time playing with this camera but unfortunately have come to the conclusion that the low light and dynamic range performance is not really good enough. The camera appears to record onto the integrated Micro SD card with reasonable results but the FPV output suffers from poor dynamic range (in my opinion).

So I replaced the Boscam TR1 with a Sony Super HAD 600tvl camera. I cannot confess to have flown the camera yet but my initial impressions are that is it a marked improvement over the TR1. The Sony camera has an impressive range of on screen configuration functions including a wide dynamic range feature ..... even pointing the camera into a very bright foreground light source the background exposure is still really very good and well exposed.

I have also fitted a 5.8GHz eight channel radio transmitter module to replace the TR1 integrated transmitter.

The main bulk of the work has been constructing a Quad rear mounted subsystem housing the radio telemetry module & OSD display module. I removed the module headers and fitted vertical headers to allow the modules to be mounted together on a single board housed in a single enclosure. Enough text ..... it's easier to have a look at the video

Hope you like, any questions please fire at will !

Cheers,

Dave


Quadcopter - new FPV camera, 5.8GHz Tx & integrated telemetry + OSD unit :

 

[dtrewren]

Evening one & all,

As promised attached is a simple schematic showing how I integrated the OSD module, telemetry module, Arducopter, camera & power together. The switch can be seen multiplexing the module Tx lines into the flight controller.

Notice the RF PA is sourcing the 12V power after the UBEC, this keeps the PA, camera & OSD module all running from the same power supply. Other things are connected to the raw 12V UBEC output such as fan & gimbal.

Any questions please fire away

Cheers,

Dave

 

[dtrewren]

Morning all,

It's a posting bonanza

Now I have the OSD module fitted and working I really wanted to be able to record output from the FPV camera with the overlay
information also included. I could simple record this on the ground as my monitor screen has the ability to record video. However,
recording on the ground would suffer from reduced quality and inevitable video breakup over the radio link.

So I have hunted about and found a perfect little solid state video recording unit. The unit simple has video/audio in/out and a remote
control to select operation.

The only downside is the unit is a bit heavy and with connectors attached bulky - see attached video to see the plan for mounting
the video unit on the Quad.

Cheers,

Dave


Solid state DVR - lets take it apart and make it better !

 

[dtrewren]

Evening everyone ....

Bit of a posting tick on my part

Ok, I looked at changing the enclosure on the video recorder and in the end decided to keep the aluminium enclosure supplied
as the weight difference compared with a new enclosure was negligible and not worth the hassle swapping. I also kept the internal
top board I originally thought of discarding but did remove all the connectors and replaced with a wiring loom to make the
integration with the OSD module easier.

So I have put another little video together detailing my thoughts on the recorder and showing some live recorded output. A
very windy day so it's not great footage but shows the gear in action.

Cheers,

Dave

Any comments very welcome.

 

[Hugh Hemington]

When you pulled the DVR guts out, my first thought was you ditched your shielding and that DVR would dump all over your other gear, so it may be good you decided to stick with it!

 

[dtrewren]

Hi Hugh,

I was expecting a problem when I put the OSD & telemetry modules in such close proximity and thought I might have to add some RF shielding tape. However, so far I have not had an issue with any type of interference. I did make a conscious effort to keep the main 5.8GHz transmitter away from anything sensitive.

Now just want to get out and do some flying and try and get used to flying FPV .... it is a slightly odd feeling !

Cheers,

Dave