Author Topic: Rosetta + Anker battery + on/off switch + eliminate microUSB  (Read 384 times)

bladeslapper

Rosetta + Anker battery + on/off switch + eliminate microUSB
« on: November 21, 2020, 12:00:15 pm »
Just an idea of a modification for those who are happy with disassembly and soldering directly on to a board.
Don't attempt this if you are not completely happy as you are likely to damage the Pi.

I wanted to get rid of the micro USB sticking out of the side and also fit a power switch. This way I can leave the plug connected all the time.
The switch is a latching push-to-make that I have recessed into the case (bottom right of case) so it doesn’t get easily accidentally knocked.

The +ve is soldered onto PP2 on the Pi so that the supply is still protected but it's not the easiest to solder to. You could us one the many 5v feeds elsewhere on the 2 boards to make the soldering easier but then you miss the protection.

I put the -ve onto the HDMI shield as it had a decent size tab with few tracks close-by. Needs a hot iron with a suitably sized tip as the shield sinks the heat.

That switch isn't the most suitable as they are not rated as high as I would like but realistically should be ok. I drilled the hole to the larger collar size and then just used epoxy to stick it in. I've left enough wire so I can swap it if it causes any problems. It only just fits under the ADS-B adaptor and with hindsight the switch could have gone 1mm rearward which would have been better. Alternatively just move the USB plugs around (2 and 3 instead of 1 and 4). The push button only just protrudes from the side of the case so unlikely to get knocked but the oversize hole makes it easy to access when required.

I removed the 2 USB signal wires and sealed them up. I retained as much of the shielding as I could. I soldered a replacement 24AWG silicone wire onto the ground as this was easier to run. Lots of little bits of heatshrink to ensure nothing can short in there. The outer shrink is a glued one and the hole in the case is a tight fit. This keeps it nicely secure but I also added a cable tie to prevent pull-outs. 24gague silicone wire also from the switch to the Pi. (20 won't be necessary for this internal wiring and would be very difficult to solder to the tabs)

Oh and decent quality 3M double sided foam to stick the pack on - but not on the removable Rosetta cover so you can still get to the ports (just!)

Small mod that hopefully makes it much more simple to use.

Next will be a change to the screen mounting method I think
« Last Edit: November 23, 2020, 06:18:26 pm by bladeslapper »

AlanG

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #1 on: November 23, 2020, 10:58:03 am »
Mmmm

Not sure how efficient your GPS is going to be as you appear to have just slapped a battery pack over the top of it.
Also if using it in the vertical position as in photo the GPS antenna is not facing the sky.
You may of course be using a remote GPS but you don't say that.


Regards
Alan

bladeslapper

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #2 on: November 23, 2020, 11:09:04 am »
Yeah I considered that but it seems to work equally as well in all orientations on the window sill but then it can only see half the sky so not a fair test.
Therefore no particular plans for orientation, there's no reason why it has to be that way up when stuck to the window in the a/c, that was just the easiest for a photo.
I'll be sure to report any problems.

bladeslapper

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #3 on: November 23, 2020, 10:09:08 pm »
Out of interest, when I was looking at the 'internal' GPS, I guessed that the aerial is on the side closest to the sticker/front of the rosetta? Is that correct?

exfirepro

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #4 on: November 23, 2020, 11:01:34 pm »
Hi bladeslapper,

The GPS antenna is the square ceramic block on what is supposed to be the ‘upper’ side of the GPS dongle.

The whole Rosetta unit is designed to sit horizontally, with the printed label uppermost, which is why the antennas are articulated - so they can be positioned vertically to minimise signal loss with the unit lying flat on its ‘back’.

That said, it might well work to a degree if mounted in a vertical orientation, but as Alan has said, it is much less likely to do so reliably with the GPS antenna sandwiched between its own circuit board and your battery pack. You could of course improve this slightly by moving the battery pack to the ‘underside’ of the unit, though it will be much better in the long run to orientate the whole unit horizontally (as intended) with the battery pack underneath.

Hope this helps. Please keep us posted.

Regards

Peter

bladeslapper

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #5 on: November 24, 2020, 12:16:05 am »
Thanks for the info. Yeah that was what I thought looked like the aerial.

Unfortunately the only option is to mount it on the inside of the screen/bubble either on its suckers or on a go-pro mount (I fly various heli types). The GPS aerial is therefore always going to be facing directly towards the front seats. With this in mind, while I was looking around inside the Rosetta, I was toying with the idea of moving the dongle to a better position but decided to leave it as is for now. There is plenty of space in there so I pondered turning the aerial to face the back/bottom and either leave it in the same compartment or perhaps put it under the Pi where the array of small holes are.

Having said that, I've had it attached to my office window for the past few days and it seems to be performing OK using only half the sky - currently using 6of12 sats. I have also tried turning the whole thing around 180 on the window so the dongle is at least at the top thinking this might improve GNSS reception but it doesn't seem to make a difference. I figured that having the aerials pointing straight down would be equally as good as straight up but I'm not certain about that?

One thing I did notice which was strange was apparent interference receiving GNSS data with the dongle plugged into USB port 2 and the ADS-B adaptor in port 3. This meant that the ADS-B aerial wire had to pass directly over the dongle's antenna rather than under and this was the only thing that I could think might be the cause. I left it for 2 hours and it managed to get 3or4 satellites out of about 6 but never managed to get a fix. Any ideas?

exfirepro

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #6 on: November 24, 2020, 08:06:15 am »
Morning bladeslapper,

The antennas work equally well pointing down or up, providing they are vertical. Putting them horizontal where those in ‘other aircraft’ (or Ground Stations) are vertical results in a nominal signal loss of 3dB (i.e. it halves the effective signal in or out) - though of course actual loss varies a fair bit in practice due to normal bank angles.

I know of at lease one heli operator on the Forum who uses a GPS mouse mounted away from the unit, and several users have relocated the GPS dongle outside the case on a short USB cable to keep it horizontal where they wish to mount the unit vertically. I have also come across several instances where the user was reporting serious GPS dropouts - and on investigation found that they had mounted the unit ‘label side down’ - in one case inside a ‘spam can’ - very effectively hiding the GPS from the satellites under the metal body of the aircraft and 2 x circuit boards (it’s own and the SDR).

He was amazed at the improvement when I relocated it ‘right way up’ under a clear roof panel for him.

I haven’t personally come across the interference effect you refer to, but probably because I have only ever run the GPS dongles in the ‘upper’ ports 1 or 3 (in the Classic- Port 3 was the ‘norm’ , but this was changed to Port 1 in Rosetta as the larger Rosetta GPS will only fit in Port 1 or 2 unless you use extenders). I will take a look at this when I get a chance. Thanks for the ‘heads-up’.

Please keep us posted. We are always interested in innovation.

Best Regards

Peter

bladeslapper

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #7 on: November 24, 2020, 08:34:34 am »
Thanks for the additional information. All my uses of PA so far have been installs I have done in helis using all 3 external antennae, in fact I posted details of an old one on here recently:
http://forum.pilotaware.com/index.php/topic,1974.0.html

I've never used the PA as a portable unit mainly because it isn't portable enough for my user case - hence this little project.

It's still working fine in the office window but I'll be sure to post details of how well it works once I get in the air again. Does the Pi log the GNSS reception 'quality' for post flight analysis ?



Admin

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #8 on: November 24, 2020, 03:23:59 pm »
It's still working fine in the office window but I'll be sure to post details of how well it works once I get in the air again. Does the Pi log the GNSS reception 'quality' for post flight analysis ?

this information is stored in the track files
thx
Lee

bladeslapper

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #9 on: December 01, 2020, 11:22:41 pm »
Update from today

I did a couple of hours in the heli today and the new arrangement seems to work fine despite the GPS receiver being in pretty much the worst possible position (see pic). The only thing I noticed were a few occasions where the traffic near me seemed to jump around. It did occur to me that this might be if I have lost position data and it jumped to assuming I was facing north?

How do I go about analysing the logs to quantify the quality of the GNSS data? I have them on my PC and open in notepad++ which I have identified as not ideal!

AlanG

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #10 on: December 02, 2020, 03:20:45 pm »
Hi Bladeslapper

So sorry to be negative about this but short of placing your unit in a metal or carbon fibre box it is hard to envisage a worse positioning of your unit.  Other than the position of your GPS which you have already acknowledged, your antennas are at such an angle as to be well out of phase with any incoming signals.  You will be broadcasting your P3i signal in roughly a doughnut shape at 90 degrees to the  length of your antenna and the majority of the forward transmission is angled upwards at apparently 45 degree, making it less likely for you to trigger a response from any groundstations you are approaching and seriously reducing the range of your air to air contacts I would think.  Rearwards you are broadcasting into a couple of bags of water and your aircraft interior whatever that my be made of.
Is it not feasible to fit the battery to the base and lay the unit flat with the GPS towards the window and then have the room to set the antennas to vertical further away from the screen. 

Regards
Alan

James Rose

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #11 on: December 02, 2020, 03:27:07 pm »
How do I go about analysing the logs to quantify the quality of the GNSS data?

If you upload your track file to https://aircrew.co.uk/playback/ (info: https://www.pilotaware.com/knowledgebase/tracks) you can view how many satellites are in view in the top left corner under "Flight Information" for any given part of the flight by dragging the slider along at the bottom. It will also show when you have no GPS lock. Typically you need at least 4 satellites in view for a fix, a good installation will get 10+.










bladeslapper

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #12 on: December 02, 2020, 10:16:40 pm »
Hi Bladeslapper

So sorry to be negative about this but short of placing your unit in a metal or carbon fibre box it is hard to envisage a worse positioning of your unit.  Other than the position of your GPS which you have already acknowledged, your antennas are at such an angle as to be well out of phase with any incoming signals.  You will be broadcasting your P3i signal in roughly a doughnut shape at 90 degrees to the  length of your antenna and the majority of the forward transmission is angled upwards at apparently 45 degree, making it less likely for you to trigger a response from any groundstations you are approaching and seriously reducing the range of your air to air contacts I would think.  Rearwards you are broadcasting into a couple of bags of water and your aircraft interior whatever that my be made of.
Is it not feasible to fit the battery to the base and lay the unit flat with the GPS towards the window and then have the room to set the antennas to vertical further away from the screen. 

Regards
Alan

Yes I completely agree but no that's pretty much the best we can do. It's the same in most helis. I've done a few semi-permanent installs now and they are much better as we can position the Rosetta elsewhere. Don't forget that most helicopters cruise with a slight nose down attitude compared to when on the ground. Not by much I admit.

bladeslapper

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #13 on: December 02, 2020, 10:36:50 pm »

If you upload your track file to https://aircrew.co.uk/playback/

That's great, thanks. I looked at my outbound track and inbound track and strangely they were markedly different. Outbound (30 mins travelling west) between 5 and 8 sats and about 10 very brief moments of no GPS. Return leg East (generally) for 1 hour and between 9 and 12 sats and only 2 brief drop-outs.

I'm surprised the GPS receiver works as well as it did to be honest. I'll probably modify it anyway tho.....I can't help myself sometimes!

bladeslapper

Re: Rosetta + Anker battery + on/off switch + eliminate microUSB
« Reply #14 on: December 02, 2020, 10:41:52 pm »
Is it not feasible to fit the battery to the base and lay the unit flat with the GPS towards the window and then have the room to set the antennas to vertical further away from the screen. 

I have considered this also....on a long RAM mount attached to the window with a 3D printed adaptor for the battery to connect to Rosetta on one side and the Ram mount on the other. But, I suspect I will never bother with the hassle of carrying it around with me. It's already barely small enough to take on a day of work TBH