Log 3LVIS: (3) (L)itre (V)ery small case with (I)nternal psu and (S)creen

infoberg

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Mar 23, 2021
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Guys, I need some advice. I am going to get a new top panel custom cut with an opening for the screen and some sort of ventilation holes. But I am not sure my idea regarding how to mount the screen to the panel is a good one.

The original top is 3mm thick, I am going to get the new one in 2mm or 3mm thickness, but ordering it in 4mm or 5mm would also be possible. The distance from the top of the screen to the mounting holes is 6mm, as shown in this picture.



Ideally the screen will of course be flush with the rest of the panel. I am thinking about getting some motherboard standoffs/spacers with a length of 3mm-4mm (depending on the thickness of the panel) and just glue them onto the inside of the panel with super glue. Does this sound plausible? The screen weighs about 250 grams (roughly 9 ounces or half a pound), so it won't be putting a lot of strain on the mounts...

Grateful for any input 😉
 

Valantar

Shrink Ray Wielder
Jan 20, 2018
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Guys, I need some advice. I am going to get a new top panel custom cut with an opening for the screen and some sort of ventilation holes. But I am not sure my idea regarding how to mount the screen to the panel is a good one.

The original top is 3mm thick, I am going to get the new one in 2mm or 3mm thickness, but ordering it in 4mm or 5mm would also be possible. The distance from the top of the screen to the mounting holes is 6mm, as shown in this picture.



Ideally the screen will of course be flush with the rest of the panel. I am thinking about getting some motherboard standoffs/spacers with a length of 3mm-4mm (depending on the thickness of the panel) and just glue them onto the inside of the panel with super glue. Does this sound plausible? The screen weighs about 250 grams (roughly 9 ounces or half a pound), so it won't be putting a lot of strain on the mounts...

Grateful for any input 😉
Superglue isn't good for metal-metal bonding, but some sort of epoxy should do the trick. Americans always recommend JB Weld, it's not available where I live and sadly I don't know of anything equivalent. Any epoxy advertised for adhering metals should work though. For some extra security you can run a line of hot glue or acrylic sealant around the edge of the panel afterwards (not enough for structural support, but it'll help keep things in place).
 

SFFMunkee

Airflow Optimizer
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Jul 7, 2021
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That specific item looks way too heavy duty, but some sort of cloth webbing might be good. Be mindful that gluing cloth to metal can be pretty tricky (and messy) though, and that a robust fabric-based tape will essentially be doing the same thing. It's not like this hinge will bear much of a load :) If you can find something like this in a slightly wider style that would be my choice.
Oh 100% agree, I just couldn't find a good image of a webbing-type hinge.
I'd use webbing like what you'd get for backpack straps, lightweight and plenty strong for hinges. You could use rivet or rivet-eyelets then screw those in, or try an adhesive. Just make sure the ends are sewn/glued/melted down to avoid fraying.

I think JB Weld is recommended because it's reinforced with some metal content in the epoxy itself, but any decent epoxy should work. Check for similar epoxy products from brands like Sika, Loctite, Permatex and Gorilla. Just verify that it's suitable for metal-to-metal applications, and that temp tolerance is reasonable (though I wouldn't expect a PC case to get much hotter than 45C anyway) and you should be all good.
 

infoberg

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Mar 23, 2021
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Thank you all for your input guys! Have to see when I will have all the necessary parts for the next build phase, we're starting a total lockdown on Monday, so no local shopping for parts is possible.

For the first step I will go with the tape/webbing hinge idea and having the lid stay open by some stands which are fixed to the lid with a hinge. But I am also still loooking for some other solution for that (beyond the actuators I want to use eventually), these cabinet door openers from IKA would have been perfect if they were 1cm shorter:

I am still trying to find shorter ones that will also fit in the 1cm space between mainboard and the side elements of the case.

On the other hand using standard hinges to mount the top panel to the case, I would need to make 2 parts. One about 3bm wide which would be screwed to the case and would provide an even surface to glue the hinges on. Doesn't sound much more complicated, but I will try the easy route with option 1 first and gradually improve on it if I'm not happy with it.

As for mounting the screen to the new top panel, this is fairly settled (as far as the plan goes). I will glue some M3 standoffs with 4mm length to the inside of the panel with JB Weld. These are in fact the shortest standoffs I could find (no 2mm or 3mm sizes), so the panel will have to be only 2mm thick to provide a total of 6mm which will leave the screen (more or less) flush with the panel.

By the way, this is a first design for that panel, to be cut out off brushed steel:

The source I found for this has a nice configurator which let's you do some pretty sophisticated designs, for all of us who don't know how to use a CAD programm 😁 It's pretty awesome that you can enter any text and it will present it as cutouts. Still thinking about changing the text and the whole name of the project though, so I didn't place an order yet...

That's it for now, no practical progress at the moment, just more thinking and scouring the Internet for ressources and parts.
 
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BaK

King of Cable Management
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May 17, 2016
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Grateful for any input
While Epoxy is surely the way to go, I successfully attached aluminium on aluminium, after some sanding, with super glue:

By the way, this is a first design for that panel, to be cut out off brushed steel:
Heh nice!
Wondering if the screen should be 'on top' (where your label is now) when the panel is lifted, or if this is not important?
 
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infoberg

SFF Lingo Aficionado
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Mar 23, 2021
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While Epoxy is surely the way to go, I successfully attached aluminium on aluminium, after some sanding, with super glue:

That looks awesome, great job. I think I will go with the epoxy as the PC might get quite hot inside, not sure if that's a healthy environment for the super glue.

Heh nice!
Wondering if the screen should be 'on top' (where your label is now) when the panel is lifted, or if this is not important?
Well, you're right. Of course the screen should be on top. But (and there's always a lot of "buts" with this build) there are other factors to consider. On one hand, there needs the be about 3cm distance from the edge of the case to the visible edge of the screen due to the mount points. On the other hand, the cooling in this case is not ideal. As I also have another one of these cases with the glass top, I know how hot it will get without the ventilation holes for the top panel. If the screen is placed on top, the CPU fan will be completely covered, all ventilation holes would be in other areas of the panel. So it's another compromise I had to take, as much as I would have wanted the screen on top. Or am I being too cautious here?
 
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BaK

King of Cable Management
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On the other hand, the cooling in this case is not ideal. As I also have another one of these cases with the glass top, I know how hot it will get without the ventilation holes for the top panel. If the screen is placed on top, the CPU fan will be completely covered, all ventilation holes would be in other areas of the panel. So it's another compromise I had to take, as much as I would have wanted the screen on top. Or am I being too cautious here?
For a few cm difference, I think it's the right decision.
As you say, everything that can help cooling the case should be applied!
 
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infoberg

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Mar 23, 2021
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Part 8: A New Hope​

New year - new update, although I hope the next update won't have to wait until next year...

Since the last post, I have taken delivery of the JB Weld glue and the 4mm standoffs, as well as the new top panel. I put them together and basically I now have a small PC with integrated touch screen - without internal PSU or any way to lift up the screen. But it's a step in the right direction.


The panel​


The brushed steel panel (here still with the protective film) looks quite good, all the cutouts were done as requested, really good - as it turns out, in stark contrast to my measurements. The cutout for the screen could have been 1mm shorter and the whole panel 1mm wider and 1mm taller. It is not very noticeable, so I will probably keep it this way. But I am thinking about giving the panel a matte black paint finish to match the rest of the case, not the least because every single touch of the panel leaves a visible fingerprint on it.
For a first fitting without hinge or lifting mechanism, I decided to keep the screw holes as on the original panel. If I ever succeed in having a hinge-mounted panel, I will probably use a few LEDs to close the holes. You can never have enough RGB, right?
It took only about a week from the time I ordered it until the panel arrived at a cost of about 40 Euros, including shipping. I am really happy with the supplier, I can only recommend John Steel (based in France) for any orders from Europe.

The screen​

The screen has 4 eyelets to mount it with screws to something. The plan was to glue the 4mm mainboard standoffs to the back of the top panel and screw the screen into them. A first test with the JB Weld KwikWeld glue showed that it's easy to use and indeed very strong. For a change, the mounting worked as planned, which was a nice surprise. The glue job doesn't look too professional, but as it's hidden on the inside, I preferred having a strong bond to having a nice-looking one. The screen sits perfectly flush in the panel, just the cutout is slightly too large because of my faulty measurement.


First run​


As you can see, the name and theme for the project have changed slightly, trying to make it a little bit more interesting. I might be adding a dust filter and some red backlight to the "HAL9000" cutout, to better fit in with the new theme. There's still a little residue from the protective film on the steel panel, which I didn't bother to remove yet.
Connecting the screen is easy, just one USB port needed, as it doesn't seem to draw more than 4.5 Watts. I am not sure how to connect it to the HDMI port on the I/O backplate, I don't really like the cable sticking out the back like it does now. I might just file off a little bit from the back panel so I can slide the slim cable through. Temperature is quite ok, only a few degrees more than with the original panel, running around 48°C in idle.

Lift-Off​

Pursuing the hinge idea, I am still working on implementing some kind of lifting mechanism. I got myself a nice little microcontroller, the Adafruit ItsyBitsy RP2040 and a matching motor controller, the Adafruit TB6612. I chose this specific version of a RP2040 controller board because it can output 5V while operating at 3.3V. In theory, the microcontroller should be able to provide enough power for the motor controller and the motor, all of them running only off the USB power.

The ItsyBitsy controller has a Micro-USB input that will be connected to the PC via one of the internal USB headers, as the screen luckily needs only one USB connection for touch and power. These two controllers together should make it relatively straightforward to build a lifiting device with a tiny stepper motor/linear actuator.

But as this is the first time I am working with microcontrollers or Python, there's still quite some learning to do...

I plan on having an application on the PC's screen which can be used to control the lifting of the screen and maybe also do some smart home automation tasks in the future. The .NET application and the communication with the ItsyBitsy RP2040 are basically done and communication via a virtual COM port works great. Now I just need to get the motor movement sorted out and then find a way to mount the motors safely in the case. Also still looking for motors with a larger stroke, but the space in the case is a limiting factor: the height can be a maximum of 70mm and the diameter of the motor a maxiumum of 12mm, so this is restricting the available choices a lot. Ideally, I would have wanted to get something with a 50mm or 60mm stroke, but I couldn't find any that were under 70mm long.


Next steps​

ToDo: master the art of connecting the microcontroller and motor driver with the stepper motor and adressing them with MicroPython. All the samples available online are using CircuitPython and it's libraries, but I would prefer sticking to MicroPython - unless I can't avoid it. Definitely enough things left to do during the next lockdown(s)...