Auren Shield Component Fit

[biomurph]

@eyuan-creare @cab-creare-com
This issue is about the Auren Shield PCB design.

Here's a draft of the Auren Shield. Based on the EarPiece Shield.
This one is a little bit longer. It will stick out over the Tympan more than the EarPiece Shield.
The EarPiece Shield is 38mm wide by 40mm long.
This Auren Shield is 38mm wide by 44mm long.

Other Changes

• Moved the Rs and Cs above the AIC closer to it

These are the copper layers from Top to Bottom. lmk what you think.

GND layer

1.8V layer

GND layer

3.3V layer

[cab-creare-com]

@biomurph Would you share the schematic?

[biomurph]

On the road for a couple hours. Will add when I land

[biomurph]

@cab-creare-com Just pushed the pdf.
Please find it here
https://github.com/Tympan/auren-hardware/blob/main/auren-shield-schematic.pdf

[cab-creare-com]

@biomurph Please add a 33R in series with both PDM_CLK (between P2 and J3) and PDM_CLK1 (between U2 and J3). Those are series termination resistors to avoid transmission line ringing.

[biomurph]

@cab-creare-com
Added the two 33R in series with the PDM clock lines.
Schematic https://github.com/Tympan/auren-hardware/blob/main/auren-shield-schematic.pdf

Here's the effected layer. Resistors added near the HDMI connector.

[b-graybill]

thanks, @biomurph - if we remove J1 and J2, can we recover the original size?

[biomurph]

@b-graybill yes, removing the audio sockets J1, J2 will allow room for the HDMI within the outline of the Ear Piece Shield this was designed after. If you want to go that route, do you want to keep the mic and headphone circuits, and change the connector to solderable pads?

[b-graybill]

That sounds great, @biomurph - thanks!

[biomurph]

Resized the board after removing audio jacks and replacing with solderable header rows.
PCB is now 38mm wide and 40mm long. Same size as the Ear Piece Shield.
The HDMI connector will stick out beyond the PCB edge the required amount per datasheet.

Shcematic https://github.com/Tympan/auren-hardware/blob/main/auren-shield-schematic.pdf

@cab-creare-com @b-graybill If this looks good to you, please green light and I will get the job underway.

Top Layer GND

In 1 Layer 1.8V

in 2 Layer GND

Bottom Layer 3.3V

[cab-creare-com]

@biomurph Would you pull J3 pins 15 and 16 (TP1 and TP2) out to solderable pads?

Otherwise, looks good.

[biomurph]

Oh, duh. Of course!
https://github.com/Tympan/auren-hardware/blob/main/auren-shield-schematic.pdf

Here are the finished layers

[cab-creare-com]

Looks good to me. Thanks for all the silkscreen labels!

[b-graybill]

@biomurph - can you export a STEP file of this board populated with components? Then we can revise the enclosure that houses the main board and shield in one. Thanks!

[eyuan-creare]

@biomurph - can you export a STEP file of this board populated with components? Then we can revise the enclosure that houses the main board and shield in one. Thanks!

I remember this being a bit tricky. It you run into issues with STEP, check out this lnk: https://community.element14.com/products/pcbprototyping/b/pcb-blogs/posts/kicad-6---exporting-models-to-mechanical-cad-programs-1415903452

While you are at it, you might export it under the other file types that KiCAD offers as well.