ESP32: Enclosure Updates for ESP32 Based Frog

[keenanjohnson]

Hey @eaudiffred !

As we discussed in our team call earlier, I have fairly high confidence in the new processor that we would use for the microcontroller based version of the Frog.

Here is the actual part and link to adafruit: Adafruit ESP32-S3 Feather with 4MB Flash 2MB PSRAM - STEMMA QT / Qwiic

Implementation Notes

The power connector is a USB Type connector again shown on the left hand side of the image below. I imagine we would want to orient the board such that the power connector faces down like our previous designs

One thing that is a bit annoying is that USBC Power Adapters tend to be fairly large and not designed for outdoor applications, so I'm wondering if it might be worth designing around a USBC to Barrel Jack to USB C Adapter like this one?

Electrically this would be fine, but physically it will be perhaps mechanically wasteful as that adapter is almost the same length as the whole ESP board haha.

Would love any thoughts or opinions there :)

[muditprotect3d]

Great feedback @keenanjohnson, thanks! I also printed one last night, but I tweaked the dimensions ahead of time. I was able to get the board to slide in, but it was still a little too tight. I think 22.7mm, the exact width of the board will work well. we can increase tolerance in the slide then if it was too tight fitting in?

[eaudiffred]

@muditprotect3d, Yes. I put the edits in the main file.

[muditprotect3d]

@eaudiffred sounds good! Sorry about the dimensioning issues there. I'll also get a test print going for today

[eaudiffred]

@muditprotect3d, no worries! That's why we test print! Definitely an iterative process.

[keenanjohnson]

I can definitely try a print with the different cable routing @eaudiffred, but yeah I'm sorta leaning towards the right angle USB c adapter unfortunately possibly being the best answer.

In order to make it work without the adapter, I think we will need to add some strain relief retention features for the cables which could help take the strain away from the connector due to the bending? I'm thinking some sort of slots or something at locations like I've hastily drawn below (in red markup) that the cable could be pushed into? What do both of you think?

[muditprotect3d]

I think that could greatly reduce the strain in the wire -- if we want to make it slightly simple in terms of design we could make it tolerances clips against the side of the wall that the wire can be pushed into?

[muditprotect3d]

@eaudiffred in terms of the modular hooks I was thinking of something like this essentially with a similar hook mechanism as the shroud and then have different types of hooks available for the user to print? Not sure if that's what you had in mind but we can talk more during our meeting tomorrow as well!

[keenanjohnson]

Do you have any bandwith to take a shot at design of those strain relief clips @muditprotect3d and I could do a test print and assembly?

As for the hanging hooks, not to be annoying, but let's try to keep that discussion separate in #171

[muditprotect3d]

@keenanjohnson sorry about that! I have a midterm tomorrow but I can take a shot at those clips right after that if that works?

[muditprotect3d]

@keenanjohnson I think @eaudiffred was doing some work on changing the enclosure design for this issue here as well: https://cad.onshape.com/documents/b3e6eeabf50d585d20f25fc6/w/da7f4373da69947f3d05d9c4/e/634db96a0c5d4c7b0ff00c45

[muditprotect3d]

I have a test print in process right now for this enclosure structure

[eaudiffred]

@keenanjohnson, @muditprotect3d, I've been messing around with the base this morning trying different shapes. I have some time to build in the strain relief. I can get it done in the next few hours and have it ready for a test print. I'll report back when done.

[muditprotect3d]

@eaudiffred sounds good! Let me know if there is anything I can help with

[eaudiffred]

What do you think of this? There is a hole in the rounded piece for a ziptie.

[muditprotect3d]

That looks great! Do you think it would be worth to include a clip on the wall for the wire here or will this be sufficient for the strain issues

[eaudiffred]

Something like this with another ziptie? The only concern I have is the print quality. I usually have trouble with small things that over hang.

[muditprotect3d]

@eaudiffred that's a good point this would probably end up printing supports under it, not sure if that's worth the pain in such a small enclosed area I agree.

[damz]

Are we giving up on being able to stack a GSM modem wing on top of the feather?

[keenanjohnson]

It is a good point that routing the cable over the top of the circuit board would make it challenging to stack a cellular feather module on top. Have you identified what the ideal feather module is yet @damz or does that still need an evaluation?

Until we do a test print we still don't know if the strain relief strategy will work (I'll complete this later today hopefully), so we're not totally committed to that direction yet. However, if we haven't finished a good selection for cellular modules, I wouldn't want to hold up the first release here waiting for the cellular parts release quite yet.

We can always revise the enclosure for a cellular module later if needed.

[eaudiffred]

I just started a test print on this file.
Base - ESP32_V2 (3).zip

I think we can route the cable back over itself to avoid the area above the board. I'll see what I can make work with this print.

[damz]

Have you identified what the ideal feather module is yet @damz or does that still need an evaluation?

I am currently evaluating the qTop Adafruit Feather Compatible LTE Cat-M1/NB-IOT/EGPRS GNSS BG96 shield. It would sit on top of the feather.

[eaudiffred]

Not great results with the test print. There isn't enough space to slide the power port into the board. The cable flexes and fits, but I can't figure out a way to plug it in...

I'm back to this option. The red rectangles are supports for the adapter.

[muditprotect3d]

I think I agree with the idea that we have already reduced material usage so much and going back to this version of the sensor design makes the overall size much smaller too -- having a 90 degree adapter on the BOM should be okay considering in retrospect how much we are saving on material already with this design too @eaudiffred

[keenanjohnson]

I printed the latest version and everything looks very good to me!

My only two points of feedback:

• Two screws seems adequate for holding the esp32, however it was a bit tricky aligning it initially. Perhaps the other two non screw posts could have small bumps that stick up into the two holes on the board to help initially aligned it?
• I noticed the connector wobbles a bit when plugging in, not too concerning l, but perhaps in the future something could be added to prevent that.

https://user-images.githubusercontent.com/2559382/206041760-e2a2fb6a-5ac0-4d48-be69-0911ffd4b4b0.MOyV

[keenanjohnson]

@eaudiffred should we "release" this version of the enclosure and make additional changes as we go? I can create separate issues for the things above if so.

Do you need help tagging the latest version of the onshape assembly and everything or do you have that covered?

[muditprotect3d]

@keenanjohnson do you think we could include the hooks in this release as well?

[muditprotect3d]

I think they are ready after a couple of iterations -- but I can also make more edits if needed by the EOW

[eaudiffred]

@keenanjohnson, good points. I added the bumps for alignment. I did include a hole in the pad under the 90deg adapter that can fit a ziptie to secure down the adapter. I have not tested that out yet. Did it print out ok? Would a ziptie apply too much downward pressure on the adapter?
Another option to stiffen the adapter would be to add in some kind of blocking around the adapter:

[eaudiffred]

@keenanjohnson, Yes, I think its ready to be released! If we make any changes going forward they will be minor.

[eaudiffred]

@muditprotect3d, yes. Let's include these hooks in the release. The can be added to the build instructions as options for hanging in different situations.

[eaudiffred]

Do you need help tagging the latest version of the onshape assembly and everything or do you have that covered?

@keenanjohnson, what do you mean by tagging the latest version of the Onshape assembly?

[keenanjohnson]

Oh I just meant identifying which assembly and branch was the most up to date

[eaudiffred]

@keenanjohnson, gotcha! Yes, it's this one. Do you remember how to merge it back as the main? https://cad.onshape.com/documents/b3e6eeabf50d585d20f25fc6/w/da7f4373da69947f3d05d9c4/e/c221edb50cd05a98d22970e2

[keenanjohnson]

Yup! I can do that tomorrow :)

[keenanjohnson]

Ok @eaudiffred I've merged that branch into the main branch.

[eaudiffred]

@keenanjohnson @muditprotect3d, I would vote that we close this issue and release V4. I made one small change to the Head clips this morning, so I can create a PR to get the file changed in the parts file on GitHub.

[muditprotect3d]

@eaudiffred I agree! I think we are ready to release the v4

[keenanjohnson]

I know in discord there was some discussion on some very minor revisions for the head clips based on printing results. Do we need to add that here and commit new STLs before an official release?

[eaudiffred]

@keenanjohnson, yes. I'll get the revision printed tonight and make sure it fits tomorrow morning. Then I can submit the PR to update the file tomorrow.

[eaudiffred]

Opened PR #195 for the upload of the final version of V4-Head.

[eaudiffred]

Added some posts that secure the USBC Adapter in place and eliminate the need for a ziptie. It fits the adapter I used pretty well right now.
@keenanjohnson, do you have time to print a test to see if it works out? My only concern is that different adapters might be shaped slightly differently, in which case it would be important to always purchase a specific one.

BaseV4-Test.zip

[beriberikix]

Are we concerned about water/snow ingress? Outdoor enclosures usually use Cable Glands to prevent that, like this enclosure. It also has the benefit of allowing you to use a standard cable and pass it through. I found many 3d-printable cable gland on Thingiverse that may be able to incorporate into the design.

[keenanjohnson]

@eaudiffred mu test print finished and it feels vastly more secure than without the supports and no zip tie. The posts take the force of plugging and unplugging nicely which no longer leaves me concerned about breaking the connector on the board.

[keenanjohnson]

[keenanjohnson]

The design here is an excellent place. There are certainly improvements we can make in the future and let's open specific issues for each of those.