Enclosure

A reference enclosure design for FDM printing. The measurements assume the exact modules from the bill of materials; verify against your parts before printing, module clones vary by a millimeter or two.

Case dimensions

Dimension	Size	Driven by
Length	110 mm	Battery plus PN532 side by side
Width	75 mm	Display plus encoder column
Height	35 mm	Speaker depth
Wall thickness	2 mm	Standard for FDM strength

Internal layout

┌────────────────────────────────────────────┐
│  ┌──────────────────────────────────────┐  │
│  │        ST7735S display               │  │
│  │        visible area 35 x 28 mm       │  │
│  └──────────────────────────────────────┘  │
│                                            │
│  ┌───────────┐  ┌────────┐  ┌───────────┐  │
│  │ ESP32-S3  │  │MAX98357│  │ PN532 NFC │  │
│  │ 51x25 mm  │  │18x20 mm│  │ 43x40 mm  │  │
│  └───────────┘  └────────┘  └───────────┘  │
│                                            │
│  ┌──────────────────────────┐   ┌──────┐   │
│  │ 103450 LiPo, 51x34x10 mm │   │ EC11 │   │
│  └──────────────────────────┘   └──────┘   │
└────────────────────────────────────────────┘

Placement rules that matter:

• The PN532 sits directly under the top face with nothing metallic between it and the outside. NFC range through 2 mm of PLA is comfortable; through a battery it is zero. Keep the battery on the opposite side.
• The speaker needs a grille: a hexagonal pattern with 2 to 3 mm holes over the speaker face, and an enclosed volume behind it improves bass noticeably.
• Keep the ESP32 antenna end (the side away from the USB connector) at least 5 mm from any copper or battery, and never wrap it in foil-lined material.

Cutouts

Cutout	Size	Face
Display window	36 x 29 mm	Front
Encoder shaft	7 mm hole	Front or top
USB-C	10 x 4 mm	Side, aligned with the dev board
Touch pad recess	to your pad size	Top, wall thinned to 1 mm behind it
Speaker grille	hex pattern	Front or side
SD card slot	12 x 3 mm	Side, aligned with the breakout
Charge LED light pipe	2 mm hole	Optional, above the TP4056

The touch sensor works through plastic if the wall behind the pad is thinned to about 1 mm; a small circular recess on the inside face does it.

Mounting

• Four M2 standoffs (5 mm) under the ESP32 dev board.
• The display and the PN532 sit in printed clip frames rather than screws; both boards have fragile mounting holes.
• Corner assembly: M2.5 x 8 mm screws into heat-set inserts, or self-tapping into printed bosses.

Print settings

Setting	Value
Material	PLA or PETG
Layer height	0.2 mm
Perimeters	3
Infill	20 percent
Supports	Only for the USB cutout overhang

PETG tolerates a warm car dashboard much better than PLA; if the device will live near a window, print PETG.