Author Topic: Custom case designs  (Read 5074 times)

Ian Melville

Re: Custom case designs
« Reply #15 on: January 30, 2018, 12:31:10 pm »
Hi Alan, would moving the switch allow enough space for a fan?

alan_d

Re: Custom case designs
« Reply #16 on: January 30, 2018, 12:45:14 pm »
Hi Alan, would moving the switch allow enough space for a fan?
Yes, that's possible. The switch could go horizontally on the other side below the GPS dongle.
Something like a 30mm 5v fan?
It would shorten the battery life a bit, would need to test to see by how long...

rogellis

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Re: Custom case designs
« Reply #17 on: January 30, 2018, 03:22:45 pm »
Interesting ‘enclosure’, Alan. 

But I am not sure about your external connector slots, as they are too easily disturbed or disconnected.  I have gone for the opposite philosophy, of having all the connections inside the box so they cannot be disturbed.  And the result is below, with just three leads comming out.   The dc converter is inside the box too.

(Update:  I see you are working with a 5v internal battery, which makes things simpler.  Mine is for a 12v external battery.)

If I was better at engineering, I would probably have screw connectors on the exterior of the box for the two aerials, like you have, to make removal of the box for servicing easier.  (The aerials are remote, and fixed to the airframe.)

Roger



.

« Last Edit: January 30, 2018, 03:37:02 pm by rogellis »

Keithvinning

Re: Custom case designs
« Reply #18 on: January 30, 2018, 03:35:52 pm »
Alan

Nice work
Have you done any work on testing the Lipo battery. These can get very nasty if not charged right and cause fire?

Regards

Keith

alan_d

Re: Custom case designs
« Reply #19 on: January 30, 2018, 03:52:18 pm »
But I am not sure about your external connector slots, as they are too easily disturbed or disconnected.  I have gone for the opposite philosophy, of having all the connections inside the box so they cannot be disturbed.  And the result is below, with just three leads comming out.   The dc converter is inside the box too.
Because of the internal battery and wiring between the battery module and the Pi, there is no need for any connectors in normal use. Just switch on and leave it alone.
Only connect to charge it - typically on the ground.

Have you done any work on testing the Lipo battery. These can get very nasty if not charged right and cause fire?

The off-the-shelf Pi battery module is an existing tried-and-tested design, with the battery charge controller etc on-board. Full info here: http://www.raspberrypiwiki.com/index.php/RPI_Lithium_Battery_Expansion_Board_SKU:435230
There is a red charge LED on the opposite side of the board, and a hole in the case to match. It charges from a micro-USB cable (the same as you usually use to power the PAW).
It takes about 2 hours to charge from flat, and automatically stops when full.

JCurtis

Re: Custom case designs
« Reply #20 on: January 30, 2018, 05:27:23 pm »
If you were looking to run 2 or 3 LiPo batteries in parallel to increase capacity, without monitoring each cell during charging, then things could get quite interesting if a cell were to degrade.  That board is designed to charge a single LiPo cell, so it would be interesting to know what capacities and topologies it supports.

I would be *very* careful about putting a modified unit in a cockpit without some serious testing, including emissions, as the base board seems to have no CE mark.  If you looking to sell these in the future you will legally have to prove compliance with the various regulations even with an unmodified unit.

Apart from that, neat idea, there are a few rapid prototyping / small run companies that can produce things like that in small quantities (1-100's) quite quickly should you decide to take things further.
Designer and maker of charge4.harkwood.co.uk, smart universal USB chargers designed for aviation.  USB power without the RF interference. Approved for EASA installs under CS-STAN too.

alan_d

Re: Custom case designs
« Reply #21 on: January 30, 2018, 05:37:30 pm »
I would be *very* careful about putting a modified unit in a cockpit without some serious testing, including emissions, as the base board seems to have no CE mark.  If you looking to sell these in the future you will legally have to prove compliance with the various regulations even with an unmodified unit.

Good point. I don't see the point of re-selling parts that anyone can buy from Amazon, only the case and hardware to assemble it.
I'll design a version of the case without the battery board also, when I get time!

Ian Melville

Re: Custom case designs
« Reply #22 on: January 30, 2018, 07:51:06 pm »
Hi Alan, would moving the switch allow enough space for a fan?
Yes, that's possible. The switch could go horizontally on the other side below the GPS dongle.
Something like a 30mm 5v fan?
It would shorten the battery life a bit, would need to test to see by how long...
I was thinking of the fans used in the Statux case, some of us have a few kicking around  :) which measure 30mm square, and are 5v 0.2A

If you switch to low power RTL-SDR you will be better off, just  :)
« Last Edit: January 30, 2018, 07:52:54 pm by Ian Melville »

alan_d

Re: Custom case designs
« Reply #23 on: January 30, 2018, 08:00:02 pm »
I was thinking of the fans used in the Statux case, some of us have a few kicking around  :) which measure 30mm square, and are 5v 0.2A

If you switch to low power RTL-SDR you will be better off, just  :)

Yes, I have one here, also from a Statux case ;)
I'm playing with the design now to move the switch to the opposite side, turn it 90, then mount the fan where the switch was.
I'd say a few holes at the antenna end of the box should encourage airflow from the fan past the dongles, battery voltage controller and Pi then out by the antennas.

Ian Melville

Re: Custom case designs
« Reply #24 on: January 30, 2018, 09:15:35 pm »
If you were looking to run 2 or 3 LiPo batteries in parallel to increase capacity, without monitoring each cell during charging, then things could get quite interesting if a cell were to degrade.  That board is designed to charge a single LiPo cell, so it would be interesting to know what capacities and topologies it supports.

I would be *very* careful about putting a modified unit in a cockpit without some serious testing, including emissions, as the base board seems to have no CE mark.  If you looking to sell these in the future you will legally have to prove compliance with the various regulations even with an unmodified unit.

This is one area that I have concerns. I have spent a lot of time around LiPos over the years, and a had a few that puffed up, but not caught fire. They frighten me. I use the latest hi-tech chargers, but this is no guarantee that it will be safe. In an aircraft, I would prefer to see Lithium-Ion batteries (LiFePO4), or 4 Eneloop AA cells, and charged away from the unit.  Along with extended flight time, that was why I asked about a design with removable batteries.

look696

Re: Custom case designs
« Reply #25 on: February 04, 2018, 01:18:05 pm »
What about packing those LiPos into a firesave cover, like they are for charging? Would mean bigger case, but for safety?
D-ERGM
1966 Beech Musketeer Super III
LOAV

JCurtis

Re: Custom case designs
« Reply #26 on: February 04, 2018, 02:35:48 pm »
What about packing those LiPos into a firesave cover, like they are for charging? Would mean bigger case, but for safety?

The aim is to have a charging system designed to handle the cells proposed, looking to add in something to contain the result if that isn't done is kind of the wrong approach.  These cells can fail not just during charging, the design needs to cater for errant cells.

Its really a case of taking the hit and always doing the right thing with battery technology.
Designer and maker of charge4.harkwood.co.uk, smart universal USB chargers designed for aviation.  USB power without the RF interference. Approved for EASA installs under CS-STAN too.

alan_d

Re: Custom case designs
« Reply #27 on: February 07, 2018, 02:25:22 pm »
Update...
The nice people at Pilot Aware contacted me to advise that 'PilotAware' is a registered trademark, so they would not allow me to write 'PilotAware' on my case, but I could sell it as a 'Case for PilotAware'.
So, I've removed the black text from the case lid.
Also, as a few people here and PilotAware themselves have concerns over the lithium battery used in the Pi power module, I have designed a battery-less version of the case, pictures below, complete with 30mm cooling fan.
The fact that this is the same battery technology used in most power banks that are the usual method of powering kit like this when the aircraft doesn't have a socket, and those are considered safer seems a mystery to me, but OK..
Conveniently, there are 5v and GND pins on the PilotAware module nearby which are ideal for powering the fan. I'm waiting for some short USB plugs to arrive to see if they will clear the fan as a plug-and-play fan power option. Space above the SDR dongle is tight.

If anyone is interested, I should be able to offer this as a kit complete with fan, antenna/cable and fixing hardware soon, or just case + hardware sooner if you have your own antenna etc.
I modified the original battery version to move the power switch and add a fan, for anyone who might be interested in that version, and the associated risks. :-\

I need to confirm the costs of the SDR antenna/cable, fan, hardware etc, but i'd expect the complete case kit to be in the region of £20-£30 if anyone's interested.

alan_d

Re: Custom case designs
« Reply #28 on: March 06, 2018, 01:23:21 pm »
All, the design has evolved a bit to allow a USB connected fan, but I finally now have all the parts so they are listed on ebay :)
https://www.ebay.co.uk/itm/162932416827

Alan.

AlanK

Re: Custom case designs
« Reply #29 on: March 06, 2018, 01:31:43 pm »
Looks good, will no doubt pick one up once I can convince others to share the PAW so I can stop paying for it all myself :)

Quick Q - why have option without lugs?