HM Case Customizer on Thingiverse


 

Tony L-Iowa

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Why does the 1A+ Pi selection put a notch in the case near the RJ45 jack of the HeaterMeter v4.3? I guess I need a connectorless customization for the Pi 1A+? The wifi USB connector is inside the case on the Pi.
 

Bryan Mayland

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Doesn't the 1A+ have a single USB jack that sticks out? Oh snap I guess it does not. I don't have one here so I used a drawing I found on google when I designed it. The Zero version would probably work as well, but without the little shelf. I can make the A+ version not have the bulgey side but do have the little shelf and microsd recess bit. Will that work?

Who the heck can find a Raspberry Pi 1A+! I came to hate the A varieties because the USB kernel driver for the A's USB host was always so flaky and would cause the wifi dongles to stop working.
 

Bryan Mayland

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Haha wow, people still have them eh? Well I am certainly not going to spend $30 to make the case fit an obsolete piece of hardware. I can certainly update the model file with the right dimensions though if the 1A+ fits the Zero case (and I'll include the other mounting bits).
 

Tony L-Iowa

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I printed the connectorless version and the A+ fits in it fine. The USB wifi dongle is just inside the case. :) I just bought this A+ Pi on Amazon a few weeks back. I think they come about on occasion. I now have two Pi Zero W's and will start to try them out. Love the new integrated wifi as an option.
 

Tony L-Iowa

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Also, have you considered a lower cost no LCD version and case being supported? I suppose the build would just exclude the LCD stack card and stack mating connectors? That would just leave the case without LCD/button holes?
 

Bryan Mayland

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Also, have you considered a lower cost no LCD version and case being supported?
The parts are separated out on the wiki and Mouser projects because I figured some people would want to do just this and the circuitry is divided such that the base doesn't need the LCD. I don't offer it as a kit option just because then I'd need to have separate parts lists and probably end up with extra LCD/Button boards because it would be difficult to anticipate how many people would want each variant. It isn't worth the hassle for me :)

Thanks for the information about the A+ fit, I'll update the file so it doesn't put any holes in the side. Does it need the little bump out bit to accommodate the wifi dongle or can I remove that too like I do on the Zero?
 

Tony L-Iowa

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I don't think the bump out is needed. I don't mind the bump being there so it's probably just as simple to add the a+ to the connectorless option and keep it independent. Another thing you may want to mention is for folks to pay extra close attention on different LCD's fitting into the case. I tried getting a RED LCD and it worked but its datasheet dimensions on the outside were just slightly bigger than the standard yellow LCD. The difference was only about 1mm but it was enough that I had to cut away a little plastic (~ 3 print lines) so the LCD frame went down into the pocket you created with the case. Do you make the SCAD files available if someone needs to make a custom tweak like that on the case design? That thingiverse customizer is pretty neat but I think it's options that you must have preset into it?
 

Bryan Mayland

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That's odd, I thought they all had the same dimensions. Especially odd is that the dimensions I used are 26.3mm for the frame, not the smaller 25.2mm size (look in the lcd_neg function). The SCAD file is on the thingiverse page on the Files tab, and is also available in the github repository. The customizer only shows special variables defined at the top of the scad file.
 

Tony L-Iowa

TVWBB Fan
The datasheet of the red one I had shows 26.3 +/- 0.2. I did test the yellow LCD (with datasheet showing 25.2mm) and they fit perfectly. Would it hurt if you tweaked that 26.3mm to 27mm or 27.3mm on the lcd_neg function? I think things feel pretty tight in the case when I sandwhich them all together I wouldn't think the LCD would slop around if left another 1mm of tolerance. I didn't pull other datasheets to see if the other color LCD's are closer to the 25.3 or 26.3mm marks.

On another note I looked at your SCAD file. Pretty impressive from what I see. Seems I have a lot to learn about 3d modeling and the OpenSCAD tool. I've fiddled around with AutoCAD 2017 some and it has lots of features for pretty much doing anything. It's definitely not free though.
 
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Bryan Mayland

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If you look at the finished scad file, you might think the whole thing was created in my mind then just typed in and it really looks impressive. In truth, I just made a cube and I just kept adding and removing stuff and printed something like 30 prototypes as I went.

The tolerance is tight because the screw holes are there and if you make it 1mm larger, there's not enough space to put perimeters between there and the screw holes. I might remove the screw holes entirely though because the locklip holds the LCD pretty well. Is that the only dimension that has an issue?
 

Bryan Mayland

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I pushed up a new revision of the case to thingiverse. I made the LCD bezel relief 1mm larger (27.3mm now), but moved it down 0.5mm. The grab latch I left in the same place so you'll get an extra mm overall. I found an error in my math which made the part where no plastic is 0.3mm too high as well. Those screw holes are now gone.

All the parts there are done off the dimensions in the datasheet and everything about all that stuff is relative to hole in pin 1 of the LCD connector. If I start moving it around too much then it won't line up once assembled (the LCD or the buttons). If I make it too loose with the dimensions then the slightly smaller LCD will slop around in there too. I've got a couple of those low power backlight LCDs here in the lab and they fit into the new dimensions (they are 26.5mm actual) but they do sort of snap into place. At the very least you should be closer, but 1mm probably isn't enough to make up 3 lines of plastic.

Maybe try printing just that part until it gets that high and then abort the print and measure the hole? 27.3mm should be enough to fit any of these LCDs.
 

Bryan Mayland

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Also, have you considered a lower cost no LCD version and case being supported? I suppose the build would just exclude the LCD stack card and stack mating connectors? That would just leave the case without LCD/button holes?
Just for my own reference if I ever go back to this (case interior dimensions):
Standard HeaterMeter build: 95.75mm x 95.25mm x 32mm
Headless HeaterMeter build: 95.75mm x 95.25mm x 22.4mm
Pi Zero Headless HeaterMeter build: 95.75mm x 70.25mm x 20mm

There would have to be a lot of rework of all the internal bits though, as everything expects the case to be at least a certain height so the nuttraps start getting split across the case, the lips run into board components, etc. It is non-trivial to made the modifications but you can see how tiny it would make the device even without doing any changes to the PCB layout to optimize the space.
 

Tony L-Iowa

TVWBB Fan
Quick and dirty option could be to just cover the button/lcd/led holes with solid (keeping case dimensions the same) and put up a couple of support pillars to hold things squeezed together where the LCD stack item would have been? I know I never use the buttons/lcd but I build my units with them anyway just because it looks fancier. I've been considering a headless case more just as some added potential "rain" protection. Whenever there's a chance a rain I usually throw my HM unit into a tupperware container that I trimmed some slots out of for the wires.
 

 

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