Transparent "Lidded" Enclosure

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Have had a request from a designer friend who is looking for an existing enclosure with a clear lid. His product is using the display from a Nokia 5110 and he wants it all enclosed and capable of operating in a marine environment... so probably  with an O-ring seal of sorts. Hammond came to mind, but I am sure there are others.

 

The pcb is approximately 100mm by 80mm. He hopes for production quantities... eventually.

 

Suggestions sought with thanks.

Ross McKenzie, Melbourne Australia

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I use a nice Bud box with transparent lid. PN-1323-CMB. Exterior 115mm x 90mm and 55mm high with the lid on. Inside, corner notches are required in a circuit board. Four interior mounting bosses. IP65 which is good but not submersible. Mounting tab at each end. Available from Mouser. 

 

On my next product, I am changing to a Polycase WH-02. Very slightly larger, transparent lid, but the lid is hinged and latched so that no tools are needed to get in. That is good in inaccessible locations like high in a tree. Oh, its also only 3/4 the price of the Bud box. The lid is not quite high quality optical, I suspect.

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

Last Edited: Mon. Nov 23, 2020 - 08:02 AM
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Another option might be a case from Pac Tec Enclosures.

 

I used the Model  SODCT6235-2.5 for a couple of projects.

 

It is (was) IP 65 rated, and had a rubber gasket seal.

 

I don't think this particular model is still made.

 

FYI:  CT = Clear Top.

 

They have many, many models of cases, so it will take a while to find what is suitable for his project.

 

When I laid out the PCB I didn't know how to shape the corners of the board's edge, so it underwent a "Cornerectomy" on the benchtop before I installed the components.

 

JC

 

(Pre_shrunk JS)

 

Edit:

 

I can't seem to edit the image size... <sigh>

And the forum shrunk the image horizontally, it is actually more of a rectangular box.

 

JC

Last Edited: Mon. Nov 23, 2020 - 09:50 PM
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The box that DocJC shows has the same "corner problem" that the Bud box does. It looks very similar, in fact, with the same kind of gasket. The Polycase box is more rectangular inside but still requests notches at the board corners because the bosses for external hardware mounting are several mm higher than the board mounting bosses. Major oversight, seems to me. For me, I have daughter boards that plug in at the ends and over-hang those cutout areas, so I'm OK with that.

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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DocJC wrote:
It is (was) IP 65 rated, and had a rubber gasket seal.
I recall the issue (IIRC, burps air around the gasket)

In Avon Ohio is Polycase; the following is a bit short on one dimension :

ML-34F | Outdoor NEMA Enclosures | NEMA 4X Rated Boxes

with an IP68 vent accessory though not much air flow (so, limited power dissipation)

Vent Plug | Cable Management & Venting Accessories

 

P.S.

DocJC wrote:
I can't seem to edit the image size... <sigh>
May need to be patient (wait one or two minutes, was faster)

 

"Dare to be naïve." - Buckminster Fuller

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John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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gchapman wrote:
DocJC wrote:
I can't seem to edit the image size... <sigh>

May need to be patient (wait one or two minutes, was faster)

This has been a know issue for a long time now: https://www.avrfreaks.net/forum/...

Top Tips:

  1. How to properly post source code - see: https://www.avrfreaks.net/comment... - also how to properly include images/pictures
  2. "Garbage" characters on a serial terminal are (almost?) invariably due to wrong baud rate - see: https://learn.sparkfun.com/tutorials/serial-communication
  3. Wrong baud rate is usually due to not running at the speed you thought; check by blinking a LED to see if you get the speed you expected
  4. Difference between a crystal, and a crystal oscillatorhttps://www.avrfreaks.net/comment...
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I edited the post and shrunk the picture to 1000 pixel wide.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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I've used a few of things like these:

https://www.eaton.com/us/en-us/c...

 

They survive reasonably well in marine environments. Might be a bit of overkill for the intended application though.

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Said designer friend here smiley.  Thanks Ross, starting a thread here is a really good idea.

 

What I'm working on is a marine autopilot, from the design and software here:

 

  https://www.youtube.com/watch?v=...

  https://www.pypilot.org/

 

Here are some pictures of my v0 autopilot.  Since it's really a collection of off-the-shelf modules, there's no PCB and I've just connected all the modules together with wires for a test (it worked).  Everything was jammed into a sealable lunchbox.  

 

  https://photos.app.goo.gl/kWuzHooS4Fmwunc19

 

You can also see the 10x10cm V1 PCB I designed (0805 components).  It works but I haven't sailed with it (we're just coming out of the world's longest lockdown).  

 

I've started working on the V2 board, which will be about 95x82mm, and uses 0603 components:

 

  V2 PCB

 

The board is designed to provide bidirectional control of a 12V motor at up to 30A.  I'd like to try these out on a few boats over summer, with the possible goal of it becoming a side business.

 

My original question to Ross was in search of enclosure ideas.  The sea is an unfriendly environment for electronics.  The air corrodes things over time, and it's even possible for a wave to climb into the cockpit with you (almost as much fun as a 'roo coming through the windscreen when you're driving).    So everything needs to go into a sealed box, with cables going through cable glands.

 

Requirements for the enclosure are that they fit the PCB (PCB could be redesigned to have corner cutouts), the front is clear (so the LCD can be read), be at least 115mm wide to fit the membrane keypad, and ideally, to have mounting flanges.  I followed Ross' suggestion and looked at the Hammond offerings.  I'm surprised to see that Hammond boxes here in Australia are reasonably priced on Element14/Farnell.  And when looking there, I noticed Serpac.  Gosh they have some nice enclosures:

 

  https://www.serpac.com/

 

In particular, for my needs, the RBF series:

 

  https://www.serpac.com/rbf-serie...

 

I can probably push things around to fit in an RBF53. AUD25.95 (USD16.27) from Element14.

 

  https://au.element14.com/serpac/...

 

Any ideas for enclosures which are cheaper and/or nicer?  (For example, rounded edges)

 

Thanks!

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So who is doing the boards for you now?...... cheeky

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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This company has some very 'nice' enclosures. With prices to match. I have used some extruded enclosures of theirs with nice die-cast endplates. Have survived quite well being exposed, but to to marine environments. 

http://www.takachi-enclosure.com

 

Make sure any screws etc are stainless steel. Plated steel won't last. The other thing to consider is UV. Cheap plastics will discolour and turn to chalk. For sealed enclosures, put a dessicant bag inside. Unless hermetically sealed, boxes will 'breathe'.

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js wrote:

So who is doing the boards for you now?...... cheeky

 

G'day JS.  I like JLC, especially because they'll also load 95% of the SMT parts.  And since you kinda asked, JLC and one other supplier were my main suppliers back in the day.  So much fun navigating their 中文 websites, and talking Chinese to their customer support.  Things have all changed now.  

 

 

Last Edited: Tue. Nov 24, 2020 - 03:58 AM
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Cool ... and well done!

CapnKernel wrote:
... with the possible goal of it becoming a side business.
Linux is reasonably rated on SIL; there are RTOS that have greater SIL.

Consider an RTOS?

Reasons :

  • liability roosts ... on whom or what
  • safety standards and a software development process
  • autopilots don't need a complete operating system

 

Raspberry Pi have a reduced temperature range (flash and DRAM will become faulty at some temperature below freezing); there are

  • Python on some MCU and RTOS
  • Industrial SoM (Linux, bare board)

CapnKernel wrote:
Requirements for the enclosure are ...
UV resistance?

A sunshade will help though UV will reflect off water.

IIRC, polycarbonate can be "buffed" to remove the yellowing due to UV exposure.

Polycarbonate can be coated for scratch resistance.

 

Power dissipation?

Raspberry Pi produce significant heat.

CapnKernel wrote:
... to fit the membrane keypad, ...
fyi, an operator's finger pressure can be sensed through sheet aluminum or stainless steel.

 


SIL - Safety Integrity Level

Zephyr Project RTOS – First Functional Safety Certification Submission for an Open Source Real Time Operating System - Zephyr Project

zephyr/boards/arm/sam_v71_xult at master · MicrochipTech/zephyr · GitHub

micropython/ports/zephyr at master · micropython/micropython · GitHub

Zerynth Integrations | Zerynth

Raspberry Pi Compute Module 4

[page 13]

...

Operating temperature range: -20°C - +85°C Non-condensing. ...

Sama5d27Som1EKMainPage < Linux4SAM < TWiki

atmel-software-package/target/sama5d2 at master · atmelcorp/atmel-software-package · GitHub

Giant Board - Crowd Supply | Mouser

 

Implementing Metal Over Capacitive Touch Sensors (Microchip)

 

"Dare to be naïve." - Buckminster Fuller

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gchapman wrote:

Cool ... and well done!

 

Thanks!

 

gchapman wrote:

Power dissipation?

Raspberry Pi produce significant heat.

 

While the RPi 4 you linked to generates lots of heat, power consumption of the Raspberry Pi Zero W I'm using is about 200mA max when doing autopilot duties, so that's about 2½W, which I can accept.  The unit can be totally sealed and won't need a fan or air ingress/egress.  

 

I'm currently using a VNH5019 for the motor control.  Worst case resistance is 37mOhm for the H-bridge in the chip, plus 9mOhm from the reverse polarity MOSFET.  A normal load is 12V at 1A.  P = I²R = 1 * 1 * 46 / 1000 = 46mW.  At 12V and /30A (peak current on a hydraulic system), this would generate P = I²R = 30 * 30 * 46 / 1000 = 41W.  That power is likely to be intermittent, either when stalled (end of travel), or very rough conditions and the gains are set to work too hard.  The unit monitors current and temperature and handles it appropriately.  

 

gchapman wrote:

Consider an RTOS?

 

Yes.  The existing software runs on Linux, which takes time to boot.  I don't think that's acceptable for an autopilot.  At present, the RPi software is in Python, and there's an Arduino nano running C code which does the motor control, fault detection, and analog and digital sensing (RPis don't have any analog inputs).  The Python software has recently been ported to the ESP32 running MicroPython, and my goal is to switch to the ESP32.  (I have some ESP32 modules here with psRAM that I'll try).  I'm also thinking that since the ESP32 is dual core, one core could run MicroPython, and the other core could run the motor+I/O C code.

 

gchapman wrote:

CapnKernel wrote:
... to fit the membrane keypad, ...

 

fyi, an operator's finger pressure can be sensed through sheet aluminum or stainless steel.

 

Worth thinking about, thanks.  At the moment I'm using these:

 

  https://www.ebay.com.au/itm/3027...

 

I don't expect them to last too well, but they're cheap and easy to use, so that's what I have for the moment.  I'm considering custom moulded silicone button membranes such as on remote controls.  That also solves the problem of preventing water ingress through the keypad tail.

 

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Clearly what is missing from this Thread is a picture of the boat that is being used for the testbed!

 

JC

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CapnKernel wrote:
The Python software has recently been ported to the ESP32 running MicroPython, and my goal is to switch to the ESP32. 
Consider Microchip Technology?

Reason : PIC32MZ W1 though

  • no port of MicroPython to MIPS
  • four times the price

 

micropython/ports at master · micropython/micropython · GitHub

PIC32 Wi-Fi module | AVR Freaks

 

"Dare to be naïve." - Buckminster Fuller

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gchapman wrote:

Reason : PIC32MZ W1 though

  • no port of MicroPython to MIPS
  • four times the price

 

micropython/ports at master · micropython/micropython · GitHub

PIC32 Wi-Fi module | AVR Freaks

 

You're really selling it!

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DocJC wrote:

Clearly what is missing from this Thread is a picture of the boat that is being used for the testbed!

 

  https://photos.app.goo.gl/K6gU7oKVRQ2ivufS8  https://www.google.com.au/maps/@-39.4560277,147.3271576,1802m/data=!3m1!1e3

  https://photos.app.goo.gl/EYX3rtY6144q38rX8  https://www.google.com.au/maps/@-38.1109742,144.6538458,459m/data=!3m1!1e3

 

A bit scruffy, just like the owner.  Ross will attest.

 

 

Last Edited: Wed. Nov 25, 2020 - 12:53 AM
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Remember the old joke? "Man, looking for good woman that can cook and clean, and has a boat. Please send picture of boat."

 

Nice boat!

 

JC

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CapnKernel wrote:
A bit scruffy, just like the owner.  Ross will attest.
Will I now?

Ross McKenzie, Melbourne Australia

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Arrrrrrrr! That be a fine vessel.

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DocJC wrote:

Remember the old joke? "Man, looking for good woman that can cook and clean, and has a boat. Please send picture of boat."

 

I spent all my money on boats, broads and booze.  The rest I wasted.

Last Edited: Wed. Nov 25, 2020 - 11:19 AM
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valusoft wrote:

CapnKernel wrote:
A bit scruffy, just like the owner.  Ross will attest.
Will I now?

 

Could attest laugh.