Cable for Sensirion SFM3300-D

[hydronics2]

@fpdotmonkey @Burhan-Q should I order the PCB?

Also Fletcher, just checking but you have the mating phoenix phoenix connector... maybe do a quick visual inspection to make sure it plugs in; that is, the female connector can mate with the PCB-male-phoenix connector. make sense?

[fpdotmonkey]

@hydronics2 yes order the PCB

[fpdotmonkey]

@Burhan-Q that distance is .727" or 18.47mm

[hydronics2]

OK, PCB is ordered. thanks, thomas Don't forget to order the pogo pins. https://www.digikey.com/product-detail/en/mill-max-manufacturing-corp/821-22-004-10-002101/ED8199-04-ND/1146641

[Burhan-Q]

@Burhan-Q that distance is .727" or 18.47mm

You can most easily see the difference looking at the right edge of the clip. I measured the displacement to about .075"

So I can tighten this up some if need be. I didn't know the exact spacing so I left 0.9mm clearance overall (which is about half the amount of movement you're seeing). The contact pads (on the Sensirion model) are 2.3 mm wide and have 0.24 mm gap between them, so I'll lower the spacing to 0.5mm and that should avoid any chance of a short between pins.

Sensirion SFM3300-D model

Clip current width

[fpdotmonkey]

For the print, I used Hatchbox white PLA. The spool is a few years old; idk if the material quality degrades over time.

For settings, I had the temps set to 225 end/80 plate, the "standard quality" template on Cura, and the retract speed set to 45mm/s

If there's a way to save out the entire settings file, I'd be happy to do that, but a quick search didn't yield me that result.

[Burhan-Q]

For the print, I used Hatchbox white PLA. The spool is a few years old; idk if the material quality degrades over time.

I believe it will if not humidity controlled

For settings, I had the temps set to 225 end/80 plate, the "standard quality" template on Cura, and the retract speed set to 45mm/s

Those temps seem quite high (to me), I also use Hatchbox PLA and print at 200/50 w/ default retraction speed

If there's a way to save out the entire settings file, I'd be happy to do that, but a quick search didn't yield me that result.

Would be one of the 2 CFG files found in this directory (Win10), not all settings are included, my settings for the print are shown at the bottom. You can also pull the settings from the GCODE file as well, I made a PowerShell script that pulls the settings from a Prusa Slicer GCODE files (which should be mostly similar to the Cura files).

%APPDATA%\cura\

[general]
version = 4
name = creality_base_extruder_0 #2_user
definition = creality_ender3

[values]
brim_width = 2
filter_out_tiny_gaps = True
infill_enable_travel_optimization = True
infill_sparse_density = 15
ironing_only_highest_layer = True
retraction_hop_enabled = True
skirt_line_count = 2
speed_infill = 75
speed_print = 60
support_connect_zigzags = False
support_infill_rate = 10
support_tower_maximum_supported_diameter = 1
support_tree_angle = 60
support_tree_branch_diameter = 1
support_tree_branch_distance = 0.01
support_tree_collision_resolution = 0.1
support_wall_count = 0
wall_line_count = 4
wall_overhang_angle = 70
wall_overhang_speed_factor = 80
z_seam_type = sharpest_corner

Additionally: adaptive_layers = True layer_height = 0.2 slicing_tolerance = Middle

[fpdotmonkey]

Got the board in, but it's wider than we expected. The one I 3D printed is 18.08mm wide, whereas this one is 18.88mm. We'll need to adjust the clip to handle this as presently it doesn't fit at all. @Burhan-Q

[fpdotmonkey]

In case it's relevant, the fully extended length of the pogo pins from the top surface of the board is 6.79 mm and the fully retracted length is 5.76mm

[fpdotmonkey]

The big green Pheonix connector is 16.14mm wide, 9.21mm deep, and 7.06mm above the top surface of the board

[fpdotmonkey]

Here's a drawing of the dimensions of the board from the factory + me soldering the pogo pins and pheonix connector on Sensirion Connector Board.pdf

[Burhan-Q]

@fpdotmonkey could you get me the inside dimensions (HxWxD) from the printed harness (height to under the hold downs)? The current model has an inside width of 19.80mm, so it seems there's some significant material shrinkage and knowing what the difference is will be instructive on how to modify the dimensions.

The model I printed measures: depth ~ 20.2mm height ~1.5mm (overall pcb harness height minus bottom of pcb harness to bottom of hold downs) width ~19.5mm

[fpdotmonkey]

I'm getting 18.65mm. I also noticed there was a bit of extra material there from bad printer settings, so I could change my settings to make it better. But it may also be good to note on the drawing that the slot that the board goes into needs to be clean.

[Burhan-Q]

I'm getting 18.65mm. I also noticed there was a bit of extra material there from bad printer settings, so I could change my settings to make it better. But it may also be good to note on the drawing that the slot that the board goes into needs to be clean.

@fpdotmonkey, since we have essentially the same printer and filament, maybe you could try using my GCODE file to print the same version I did. That way we can narrow down the issue to printer settings or an issue with the printer or filament. I've attached a zip folder with two versions of my GCODE, one with bed mesh leveling, the other without (since I don't know which you use). These were sliced using Cura 4.3 setup for my Ender 3 using Hatchbox PLA. I don't expect the model to come out perfectly, but it should at least allow us to compare more directly the results from your printer and mine.

40min_P-TET-000027-0.zip

Additionally, I'm open to any other suggestions or ideas to troubleshoot this issue if you or anyone else have some. Please let me know if you have any questions or issues with the attached GCODE, and I'll keep an eye out for updates on your results.

[fpdotmonkey]

So I printed a couple, and the widths of the PCB slot are 18.55mm and 17.84mm.

Other than that, I think the diagonal orientation for the part you're doing is a lot better that the flat one I've been doing. Way less cleanup and so less risk of breaking the part. There's also virtually no slop along the sensor's axis and the snap onto the sensor is very clear and satisfying.

[fpdotmonkey]

If it fits it ships

[fpdotmonkey]

Things left to do in testing

• [ ] theres a bit of slop now in the sensor axis still. Probably not consequential, but increasing that width a smidge would be nice
• [ ] validate that the electrical connection is good
• [ ] make 4 at once

After all that, I'm ready to say this part passes review

[fpdotmonkey]

Oh also, is the intention for assembling this that the PCB and the clip are put together before the clip is attached to the sensor? If not, then board doesn't do that. I think the issue could be that there's a little resistor on the sensor that would block the pogo pin from pushing forward.

[Burhan-Q]

Oh also, is the intention for assembling this that the PCB and the clip are put together before the clip is attached to the sensor? If not, then board doesn't do that. I think the issue could be that there's a little resistor on the sensor that would block the pogo pin from pushing forward.

@fpdotmonkey Yes, the aim (as far as I'm aware) would be to put the PCB into the harness and then attach to the sensor. Just to clarify, you're saying that assembling the clip and the PCB control board first, then to the sensor is possible?

[Burhan-Q]

STL file for P-TET-000027-0 P-TET-000027-0.zip

[Burhan-Q]

@fpdotmonkey are the design changes you mentioned critical for this iteration or are they lower priority (pushed out for beta)?

[fpdotmonkey]

The design change I suggested isn't critical

[fpdotmonkey]

you're saying that assembling the clip and the PCB control board first, then to the sensor is possible?

Yes this is possible

[Burhan-Q]

The design change I suggested isn't critical Okay, then I will make a new ticket for these changes and tag them for the beta prototype

@fpdotmonkey Are you willing to act as reviewer for this design since you've got the printed part(s)? You can review the assembly here on the web.

I will remove myself from the assignment while you're reviewing. Once you have finished your review, comment here with the outcome of your review, then please assign the task to me (and remove your assignment), and finally if the design passes your review, please indicate that the design is ready for approval.

[fpdotmonkey]

Review approved :thumbs-up:

[Burhan-Q]

@mechatroniks-git would you be willing to approve this part? The STL file is in the comment above and @fpdotmonkey commented about noncritical changes for the next version

[mechatroniks-git]

P-TET-000027-0 looks good to me. Approved.