HeaterMeter Hardware v4.3.3 and v4.3.4

BigDave

New member
John - Thanks for your help. You are a part searching machine. :) Without having assembled an HM before, I would be concerned about using the shorter standoff height on the 6202 version of the part at Arrow. I will go with the Harwin or the Generic version from Pololu. Hopefully Bryan will respond to my second question that will help me decide.

Bryan - While looking at the assembly videos to see if there would be a clearance issue with a shorter female standoff, I noticed the part is actually on the HM board and not the LCD/button board assembly. The parts list in the Wiki has it as part of the LCD/Button board project. Just an FYI.
 

Bryan Mayland

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What is the second question? A shorter pinheader would be fine as far as clearance on the base board to LCD board, but then the case would be 1.4mm too tall so everything in the front would be set back from the face (most importantly the LCD would flop around). The question of if the Harwin part is identical can be solved by just comparing every physical dimension.

The part is listed in the LCD/Button board parts because it is only needed if you're going to build the LCD/Button board so it isn't technically a Base board part.
 

BigDave

New member
The 2nd question was what to be concerned about by using a different header since you said you had a bag full of headers that didn't work. I figured it was just physical dimensions but I wanted to be sure. You answered it.

Thank you so much for all your help.

Now I just need my new soldering station delivered and get my parts ordered. I've got an 18 lb brisket sitting in the fridge and I would really like a decent night's sleep for once while cooking a brisket.

Thanks again.
 

Bryan Mayland

TVWBB Hall of Fame
Great! Yeah I've got some with the tail length (the bottom exposed pins) too long or too short, mating distance (the depth the pins go into it) too long and too short, things with 2.5mm spacing instead of 2.54mm, plugs that had a photo of what we want but in actuality had giant holes for big round pins, some with weird square holes that are clearly made for a different pin geometry so pinheaders fall right out, and I even have one I have yet to be able to figure out how in the heck it would be used at all because it has openings on both sides and the pins are offset to one side...

For something you'd think is so common you really gotta study the datasheets and sanity check every dimension and look for anomalies so I have virtually no confidence in recommending a new part without seeing it myself. I'd hate to make someone mad by suggesting a replacement part and have it turn out to be problematic in some way. Although you give me some brisket, I'll come over with a pair of 1x5 female connectors for ya! :)
 

BigDave

New member
I'd hate to make someone mad by suggesting a replacement part and have it turn out to be problematic in some way. Although you give me some brisket, I'll come over with a pair of 1x5 female connectors for ya! :)

I promise I won't hold you responsible if the Harwin doesn't work, the data sheet appears to show it will (fingers crossed). I would take you up on the offer and share some delicious brisket :wsm:, but it is a LONG drive from Tampa to Dallas ;)

I love stuff like this so I can get in touch with my inner engineer since I made the mistake of becoming a project manager right out of college. My wife and I had fun looking through her old controls text last night to get more info on PID control systems. (Geek couple fun - sad, I know).

Thanks again for all your help and time you have obviously put into this project.

-Dave
 

BigDave

New member
Argh! I spoke too soon. The Harwin pins are only 3.00+/-0.25 mm instead of the 3.50+/-0.1 on the 3M part.

Do you think 3 mm is long enough to get a good solder joint?

-Dave
 

Bryan Mayland

TVWBB Hall of Fame
See, that's how they get you! You think everything is identical and then boom. 3mm should be plenty long. Our boards are only 2 layer on 63mil FR4 which works out to be about 1.7mm thick. I don't think you'll even notice the difference.

And geek couple stuff is fun. Science is awesome, especially when we can bend it to our will to make delicious foods while we sleep.
 

BigDave

New member
Looks like the Harwin header worked. Did all the soldering today and booted the HM. I don't have a fan yet, but it looks like all is working.

The only issue I had was getting the buttons centered in the holes of the HM case. I don't know if I did something wrong or if it is just the nature of the beast. I had to file the lower half of all the holes to make them bigger and file the inside of the lip in the case that holds the LCD board. Looks pretty good now.

Thanks for the help and the quick shipping so I could get it done this weekend.
 

Bryan Mayland

TVWBB Hall of Fame
Great! You're in the home stretch now.

The case is designed to have a little bit of tolerance in it when it comes to fitting the parts together inside of it, but there are a lot of places in the soldering that can add up to exceed that tolerance. The biggest two are the RPi header and the two LCD header halves (the part where it goes into the LCD and the part where it goes into the LCD/Button board). The LCD header can be soldered at enough of an angle that you can easily shift the board 3mm or more. Just a small amount of angle can add to be a big error on the parts just because it is multiplied by the largest distance from the case to the solder point.
 

Ryan.Flagler

New member
Alternative Parts

So unfortunately I didn't see the discussion on the replacement header before I placed my order. Here are the parts that were unavailable to me yesterday and the parts I chose instead. Anyone see issues with them? I think everything will work, but someone more knowledgeable might save me some headache before I go to solder it together when it arrives. If these components work, we can update the wiki with additional alternatives too.

ValueDevicePartsMPNMPN Replacement
100u/25CPOL-USE2.5-6C4UPW1E101MEDUPW1E101MED1TA
8k2R-US_0204/7R9291-8.2K-RCCFS1/4CT52R822J
LCD1F, LCD2FPINHD-1X5 FJP1, JP8960105-6303-AR801-87-005-10-005101
 

Bryan Mayland

TVWBB Hall of Fame
Anyone can edit it I think but I've just made the changes with the alternate part numbers. Does the 1TA suffix on the capacitor mean that it came on a piece of paper tape for feeding into a machine?

And thanks for finding the parts and reporting back, I'm sure those will be helpful for others!
 

Ryan.Flagler

New member
Anyone can edit it I think but I've just made the changes with the alternate part numbers. Does the 1TA suffix on the capacitor mean that it came on a piece of paper tape for feeding into a machine?

And thanks for finding the parts and reporting back, I'm sure those will be helpful for others!

Based on the datasheet it looks like 1TA is some type of taping code, but I'm no expert!
 

Bryan Mayland

TVWBB Hall of Fame
I've published the updated 4.3 case with support for Pi3A+. There are also a couple of minor changes:
  • Raspberry Pi 3A+ option
  • Less round nuttraps for straight-only overhang. The old nuttrap tops had their corner radius extend over the insertion holes, which meant it was not only a bridge, but the curved part was unsupported as well. Now the curved part is supported and the overhang is a straight bridge which prints much cleaner. The old curved corner would just be a blotch of drippy filament.
  • Corner radius now a function of wall thickness for consistent thickness at corners. The curves were always 4mm radius before so the thickness of the wall along the curves would be inconsistent for any wall size other than ~2.5mm. It now scales with wall thickness to stay roughly "wall" thick through the corner.
  • Removed pin cutout by LCD. The LCD pins are even shorter than the shift register pins so there's no need to make extra space for them. Even if the pins are inserted completely incorrectly, they can still be snipped off to fit without the extra space in the case.
 

JRob

New member
Hi guys,

I just got a 3d printer and after a week of getting my feet wet printing mods for the printer itself (Ender 3 pro), I'm ready to tackle a bigger project - reprinting the case for my HM 4.3. My old one was black PLA printed by another board member, and as Bryan mentioned, it absorbed enough sunlight to warp the case.

I'm hoping someone here can give me some info on slicer settings. I'm using Cura 4.3, printing on white PLA this time (I may reprint again using PETG down the road).

My main question is how to address Bryan's comment on thingiverse to "Be sure your slicer fills the posts between the USB jacks and the locklip with something (infill or solid) or they will be brittle." I'm not sure how to interpret this comment, but saw the issues in the thread others mentioned, and I'd like to avoid them.

Any help?
 

Bryan Mayland

TVWBB Hall of Fame
My main question is how to address Bryan's comment on thingiverse to "Be sure your slicer fills the posts between the USB jacks and the locklip with something (infill or solid) or they will be brittle." I'm not sure how to interpret this comment, but saw the issues in the thread others mentioned, and I'd like to avoid them.
It just means to look at the slicer's output and make sure that the little teeny posts where the Pi's connectors come through the case are filled with plastic, and not just a single extrusion that is hollow. A picture would probably help


Same thing for the "locklip" which are the two big snaps on the top of the case that join it together, although that's rarely an issue because they're relatively big.
 

JRob

New member
Thanks Bryan! For some reason, I was thinking that you meant I needed to fill the gap across the posts with support material. Totally missed the point!

One other question: Didn't someone make a sliding back case for the 4.3? I found the files for the one for 4.2, but I could have sworn there was one for 4.3 as well. But it's been 2 years since I was looking, so I'm not sure. Just thinking about options...
 

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