Author Topic: Custom case designs  (Read 4936 times)

alan_d

Custom case designs
« on: January 23, 2018, 05:00:49 pm »
I'm working on a custom 3D-printed case design to hold the PAW hardware, a Pi battery board and a screw-on SMA mounted RTL-SDR antenna, more info below. The goal is for all the parts to be self-contained in one box without needing external cables to work.

Is there any reason for the RTL-SDR and PAW 'bridge' antenna (or whatever the correct name is) not to be close to each other? Currently I have them both on the same face of the case.

Initial testing with the Pi battery (like this: http://amzn.eu/585S6ia) shows it will run the PAW kit for about 2.5 hours. Obviously external power can be connected to give longer.
The case has openings for each port, SD card slot and all LEDs, as well as airflow holes. I've provided support for the USB GPS dongle internally (minus it's plastic housing) rather than relying purely on the USB port to support it.

Once i've finalised the design i'll post pictures - and if anyone would like a case with or without battery provision I can sell them cheaply :)
And if anyone has suggestions of what a custom case should include, let me know!

exfirepro

Re: Custom case designs
« Reply #1 on: January 23, 2018, 05:47:29 pm »
Alan,

The antennas can be placed fairly close to each other without causing any issues. There are several examples on the forum where users have put all the bits in one box, or simply cut down the 1090MHz antenna (which is receive only) and its cable and sat it on top of the standard case near the 869MHz P3i antenna to keep the unit more 'contained', without any reduction in system effectiveness.

It will be good to see your design once you get it finished.

Regards

Peter

Deker

Re: Custom case designs
« Reply #2 on: January 23, 2018, 06:11:01 pm »
Initial testing with the Pi battery (like this: http://amzn.eu/585S6ia) shows it will run the PAW kit for about 2.5 hours. Obviously external power can be connected to give longer.
And if anyone has suggestions of what a custom case should include, let me know!

Sounds interesting Alan.
I think it needs a bigger battery.  For example :- I'd want to be able to fly 1.5 hrs - consume burger - fly home for 1.5hrs
3 hrs run time would be an absolute minimum, 4 would be better.
ATB
Deker.

alan_d

Re: Custom case designs
« Reply #3 on: January 23, 2018, 07:33:36 pm »
I think it needs a bigger battery.  For example :- I'd want to be able to fly 1.5 hrs - consume burger - fly home for 1.5hrs
3 hrs run time would be an absolute minimum, 4 would be better.

I used an off-the-shelf battery for convenience. With a slightly bigger case it would be possible to use 2x 18850's to give longer run-time. I use these with Pi3's in another project i'm involved with (to scan runners with RFID tags at outdoor events) and we get about 28 hours from 6x quality 18850's running the Pi3, a 3.5" screen and WiFi connected.

Based around the current battery, it could be connected to the plane's fag-lighter socket or a power-bank to extend run-time or re-charge the battery.

The current case design is 62x128x42mm all-in.

Ian Melville

Re: Custom case designs
« Reply #4 on: January 23, 2018, 09:46:42 pm »
Is there any reason why you cannot make a trap door for the battery so that it can be swapped. I don't think many flights will be over 2 hours, so One battery outbound and another for return?

alan_d

Re: Custom case designs
« Reply #5 on: January 24, 2018, 02:56:47 pm »
Is there any reason why you cannot make a trap door for the battery so that it can be swapped. I don't think many flights will be over 2 hours, so One battery outbound and another for return?

Yes that's possible.
I'll finish the current design based around a standard Pi battery first then look at alternatives. A dual 18850 holder is probably ideal for this.

Current headache is that the power switch on that Pi power board is bypassed when plugged into charge - which means that the Pi etc is powered up when charging, and that charging takes longer than it needs.
Workaround is to remove the on-board switch and fit a DPDT switch to the case wall to both switch on the power module and feed the Pi, so when in the off position then it will charge the battery and NOT power the Pi.
As I can't find a suitable small rocker switch it'll have to be a slide switch - so design on-hold until switches arrive to design mount in case for it...

alan_d

Re: Custom case designs
« Reply #6 on: January 24, 2018, 02:59:52 pm »
Alan,

The antennas can be placed fairly close to each other without causing any issues. There are several examples on the forum where users have put all the bits in one box, or simply cut down the 1090MHz antenna (which is receive only) and its cable and sat it on top of the standard case near the 869MHz P3i antenna to keep the unit more 'contained', without any reduction in system effectiveness.

It will be good to see your design once you get it finished.

Regards

Peter

Thanks Peter. I hope to have it finished to test-fly it at the weekend. Will upload photos etc when done.

alan_d

Re: Custom case designs
« Reply #7 on: January 30, 2018, 09:42:54 am »
OK, here's the current case I designed & 3D printed, for a one-box solution without cables everywhere.

It includes a standard Pi battery (Like this: http://amzn.eu/fcGY5lz), and a SMA pigtail antenna mount + antenna from here http://amzn.eu/6UoJcMx for the RTL-SDR.

I removed the case from the GPS dongle to make it fit. There is support in the case wall for the GPS board.
The battery lasts about 2.5 hours, and it has a standard micro-USB connector for charging.
Rather than an external USB to micro-USB cable for power, I soldered the wires internally, via the switch.
The lid is dual-colour 3D printed. I tried the same with the case for the lettering but the results aren't great.
For updating you can get to the ethernet socket with the lid removed - I did this without issue today.

If anyone is interested in one of my cases, I'll list them on ebay in a few days. I'm currently waiting for proper sized M2.5 pillars for mounting between the Pi and the lid to arrive, and will probably sell it as a kit with the pillars, switch, screws etc.
And if anyone would prefer a version without the battery, i'll work on a version like that soon.

Any suggestions to improve it further welcome. I've already recessed the power switch by a further 2mm in the design, which will be in the next print.

AlanK

Re: Custom case designs
« Reply #8 on: January 30, 2018, 10:44:26 am »
Newbie here (so new my PAW hasn't even arrived yet), but as fly open cockpit in a shared machine I plan to keep this very mobile and been reading this thread with interest as it would beat faffing around with cables etc in the map pocket.  Be interested to see how this box works out and get one of you if sold as a kit that I can transpose my unit into.

PaulSS

Re: Custom case designs
« Reply #9 on: January 30, 2018, 10:54:16 am »
Very neat solution Alan (D). Have you tried your PAW inside this box yet and was the GPS reception affected? What are the box dimensions and the overall weight, with the Pi battery added.

I think you might do quite well from this  :)

alan_d

Re: Custom case designs
« Reply #10 on: January 30, 2018, 11:19:28 am »
Have you tried your PAW inside this box yet and was the GPS reception affected? What are the box dimensions and the overall weight, with the Pi battery added.

GPS when I tested it at home (with the lid on, on my windowsill in the middle of a housing estate) was showing 6 satellites. I expect more with a decent view of the sky.
I kept the lid thin over the GPS antenna ;) lid picture attached.

Box dimensions are 62x128x44mm
Total weight including both antennas is 327g
« Last Edit: January 30, 2018, 11:29:34 am by alan_d »

mmcp42

Re: Custom case designs
« Reply #11 on: January 30, 2018, 11:31:27 am »
I'm VERY interested in this
do let us know the instant they're available on a well known bay! :)

alan_d

Re: Custom case designs
« Reply #12 on: January 30, 2018, 11:48:42 am »
I'm VERY interested in this
do let us know the instant they're available on a well known bay! :)

Will do. As the pillars are needed to mount the lid, I need to wait until they arrive before I can sell it as a kit. In the meantime i'll get on with printing some and work out the costs.
Any preference of colour? I tried one in black but it looked a bit boring!
Also (to the PAW staff), what is the font of the 'PilotAware' text so I can use the correct one for the lid?

exfirepro

Re: Custom case designs
« Reply #13 on: January 30, 2018, 12:00:44 pm »
Hi Alan,

Your case looks very professional, I’m impressed!

A couple of issues you should consider though, mainly regarding ventilation. The SDR dongle tends to run hot (which has caused a couple of failures, probably linked to running in enclosed spaces) and will run even hotter shut inside your case. The Pi may also get hotter than is good for it unless some ventilation is supplied.

The Stratux cases (see Amazon) incorporate passive ventilation slots and also a fan, in fact the case has just been updated and the Mk.II (or maybe that should be Mk.III) version now incorporates 2 fans. I would suggest at the very least some ventilation slots and removing the case from the SDR dongle if you wish to avoid problems.

Best Regards

Peter

alan_d

Re: Custom case designs
« Reply #14 on: January 30, 2018, 12:09:50 pm »
Hi Alan,

Your case looks very professional, I’m impressed!

A couple of issues you should consider though, mainly regarding ventilation. The SDR dongle tends to run hot (which has caused a couple of failures, probably linked to running in enclosed spaces) and will run even hotter shut inside your case. The Pi may also get hotter than is good for it unless some ventilation is supplied.

The Stratux cases (see Amazon) incorporate passive ventilation slots and also a fan, in fact the case has just been updated and the Mk.II (or maybe that should be Mk.III) version now incorporates 2 fans. I would suggest at the very least some ventilation slots and removing the case from the SDR dongle if you wish to avoid problems.

Best Regards

Peter

Peter - yes additional holes are already on my 'to do' list. I added some to the lid already as you can see on the photos. I'll add some around the case walls also before the next print.
I've tried the lid ones at 3mm and 2mm - the 3mm looked a bit big, so the photo above is 2mm holes. Will probably use the same size for the walls.
Removing the SDR case will also help it fit better next to the wifi dongle, so will do that soon.

I'll upload some photos of a 'holey' case when complete.