Sensor modules

AXS-025 — LD2410C mmWave presence carrier PMOD module

Catalog #25 in the AruviX sensor line, level L4 (UART binary protocol + simple presence GPIO).

Level L4 ERC clean DRC clean Fab package 6 components

3D render of the AXS-025 PCB — Rendered from the PCB layout. No physical board has been manufactured.

Components#

Every placed component, with the reason it is on the board. Extracted directly from the schematic, so this cannot drift from the design.

Ref	Value	What it does on this board	Part number	Footprint
`C1`	100nF 16V X7R	Socket decoupling	`GRM188R71C104KA01D` Murata	`C_0603_1608Metric`
`C2`	10uF 10V X5R	Radar chirp-current bulk reservoir at the socket	`GRM21BR61A106KE19L` Murata	`C_0805_2012Metric`
`J1`	PMOD PLUG 2x6	PMOD peripheral plug (Digilent spec 1.2)	not selected generic	`PinHeader_2x06_P2.54mm_Horizontal`
`J2`	LD2410C HEADER	LD2410C 1.27 mm header: 1 VCC(3V3), 2 GND, 3 OUT, 4 RX (host TXD), 5 TX	not selected generic	`PinHeader_1x05_P1.27mm_Vertical`
`R1`	100R	Series protection on the module-driven presence output	`RC0603FR-07100RL` Yageo Datasheet ↗	`R_0603_1608Metric`
`R2`	100R	Series protection on the module-driven UART TX line	`RC0603FR-07100RL` Yageo Datasheet ↗	`R_0603_1608Metric`

Signals#

Net labels used in the schematic, which are also the names the HDL top level should use.

3V3 GND LD_OUT LD_TX PRESENCE RXD TXD

Production status#

Schematic ERC	0 violations
PCB layout	complete
DRC	0 violations
Fab package	exported (24 gerbers + drill + CPL + BOM)
Fabricated	no — design stage only

Source: boards/sensor-modules/axs-025-mmwave

Catalog #25 in the AruviX sensor line (../README.md), level L4 (UART binary protocol + simple presence GPIO).

Status: schematic generated, ERC clean (0/0), netlist reviewed. PCB layout not started. Not released.

What it teaches#

Two abstraction levels of the same sensor. The OUT pin (PMOD pin 1) is a plain presence GPIO — usable on day one. The UART carries the LD2410 binary protocol at 256000 baud: command/ack framing, periodic data frames with moving/static distance gates and per-gate energy values, and an engineering mode — a substantially richer protocol parser than NMEA, hence L4.

Which module variant (important)#

This carrier targets the HiLink LD2410C, which accepts a 3.3 V supply. The plain LD2410 requires 5 V and must not be fitted — there is no 5 V on this board. The pin order used for J2 (LD2410C 1.27 mm 5-pin header):

1 VCC (3V3), 2 GND, 3 OUT, 4 RX, 5 TX

This order is taken from the vendor drawing; clones circulate with other orders — verify against your purchased module before soldering the socket.

Design#

J2 = 1×5 header, 1.27 mm pitch (Connector_PinHeader_1.27mm:PinHeader_1x05_P1.27mm_Vertical, MPN TBD:).
100 Ω series on both module-driven lines: OUT (→ PRESENCE) and TX (→ RXD).
Host TXD drives the module RX directly (host-driven line).
100 nF + 10 µF at the socket (radar chirp current).
PMOD Type 3 UART with the presence output in the pin-1 position.

PMOD pin	1	2	3	4	5	6	7	8	9	10	11	12
Net	PRESENCE	TXD	RXD	NC	GND	3V3	NC	NC	NC	NC	GND	3V3

Regenerate#

python3 generate_design.py

Remaining for release#

[ ] PCB layout (keep the radar antenna face clear of copper), DRC, fab
[ ] Pin the 1.27 mm header/socket orderable part (MPN is TBD:)
[ ] Verify LD2410C pinout against a purchased module
[ ] hdl/: UART core at 256000 baud, protocol parser, presence debounce, testbench, ECP5 demo
[ ] BOM export and availability check, design-review checklist