Sensor modules

AXS-012 — APDS-9301 ambient-light PMOD module

Catalog #12 in the AruviX sensor line, level L3 (I2C). Uses the APDS-9301 instead of the catalog's original BH1750: no stock KiCad assets exist for the BH1750, and the APDS-9301 teaches the same lux- sensor lesson (dual channels, lux computed from raw counts, threshold interrupt) from stock symbols and footprints.

Level L3 ERC clean DRC clean Fab package 10 components

3D render of the AXS-012 PCB — Rendered from the PCB layout. No physical board has been manufactured.

Circuit review & bench-test guide →

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	U1 VDD decoupling	`GRM188R71C104KA01D` Murata	`C_0603_1608Metric`
`J1`	PMOD PLUG 2x6	PMOD peripheral plug (Digilent spec 1.2)	not selected generic	`PinHeader_2x06_P2.54mm_Horizontal`
`JP1`	SDA PULL-UP	Cut to remove the SDA pull-up when chaining modules	—	`SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm`
`JP2`	SCL PULL-UP	Cut to remove the SCL pull-up when chaining modules	—	`SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm`
`JP3`	ADDR 0x29/0x49	I2C address: 1-2 GND 0x29 (default), 2-3 VDD 0x49, all open (cut 1-2) float 0x39	—	`SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm`
`R1`	4.7k	I2C SDA pull-up	`RC0603FR-074K7L` Yageo Datasheet ↗	`R_0603_1608Metric`
`R2`	4.7k	I2C SCL pull-up	`RC0603FR-074K7L` Yageo Datasheet ↗	`R_0603_1608Metric`
`R3`	10k	Pull-up for the open-drain INT output	`RC0603FR-0710KL` Yageo Datasheet ↗	`R_0603_1608Metric`
`R4`	100R	Series protection on the sensor-driven INT line	`RC0603FR-07100RL` Yageo Datasheet ↗	`R_0603_1608Metric`
`U1`	APDS-9301	Miniature ambient-light photo sensor, dual channel, I2C, lux output	`APDS-9301-020` Broadcom Datasheet ↗	`Broadcom_APDS-9301`

Signals#

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

3V3 ADDR_SEL ALS_INT GND LIGHT_INT SCL SCL_PU SDA SDA_PU

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-012-ambient-light

Catalog #12 in the AruviX sensor line (../README.md), level L3 (I2C). Uses the APDS-9301 instead of the catalog's original BH1750: no stock KiCad assets exist for the BH1750, and the APDS-9301 teaches the same lux- sensor lesson (dual channels, lux computed from raw counts, threshold interrupt) from stock symbols and footprints.

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

What it teaches#

I2C command/register access with the SMBus-style command byte, integrating light on two photodiode channels (visible+IR and IR-only), the empirical lux formula over the channel ratio (fixed-point exercise), and a programmable threshold interrupt for event-driven design.

Design#

Broadcom APDS-9301-020 (chipscale, OptoDevice:Broadcom_APDS-9301), 100 nF decoupling.
Address (ADR_SEL, JP3): 1-2 GND = 0x29 (default), 2-3 VDD = 0x49, float = 0x39 — floating requires JP3 fully open, i.e. cut the factory 1-2 bridge and bridge nothing.
INT is open-drain: 10 kΩ pull-up on-module (R3), then 100 Ω series (R4) to PMOD pin 1 as LIGHT_INT.
4.7 kΩ bus pull-ups through JP1 (SDA) / JP2 (SCL), fitted by default; cut when another module on the chain provides the pull-ups.

PMOD pin	1	2	3	4	5	6	7	8	9	10	11	12
Net	LIGHT_INT	NC	SCL	SDA	GND	3V3	NC	NC	SCL	SDA	GND	3V3

Regenerate#

python3 generate_design.py

reports/erc.rpt is the last kicad-cli ERC run.

Remaining for release#

[ ] PCB layout (light aperture over U1 — no silk/mask obstruction), DRC, fab outputs
[ ] hdl/: I2C master core, APDS-9301 controller + lux math, testbench, ECP5 demo
[ ] BOM export and availability check, design-review checklist