Sensor modules

AXS-011 — Photodiode light sensor PMOD module

Catalog #11 in the AruviX sensor line, level L1 (GPIO). An ams-OSRAM BPW34S PIN photodiode in photoconductive mode with an LMV7219 comparator and Bourns TC33X threshold trimmer.

Level L1 ERC clean DRC clean Fab package 8 components

3D render of the AXS-011 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	Comparator supply decoupling	`GRM188R71C104KA01D` Murata	`C_0603_1608Metric`
`D1`	BPW34S	Silicon PIN photodiode, 850 nm peak, SMD	`BPW34S` ams-OSRAM Datasheet ↗	`Osram_BPW34S-SMD`
`J1`	PMOD PLUG 2x6	PMOD peripheral plug (Digilent spec 1.2)	not selected generic	`PinHeader_2x06_P2.54mm_Horizontal`
`R1`	1M	Photoconductive load: photocurrent x 1M = node voltage	`RC0603FR-071ML` Yageo Datasheet ↗	`R_0603_1608Metric`
`R2`	100R	Series protection on the module-driven LIGHT line	`RC0603FR-07100RL` Yageo Datasheet ↗	`R_0603_1608Metric`
`R3`	100R	Series protection on the raw analog node brought out for probing	`RC0603FR-07100RL` Yageo Datasheet ↗	`R_0603_1608Metric`
`RV1`	10k TRIM	Threshold-set trimmer, 10k, Bourns TC33X	`TC33X-2-103E` Bourns Datasheet ↗	`Potentiometer_Bourns_TC33X_Vertical`
`U1`	LMV7219M5	7 ns push-pull comparator, 2.7-5 V, SOT-23-5	`LMV7219M5X` Texas Instruments Datasheet ↗	`SOT-23-5`

Signals#

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

3V3 GND LIGHT LIGHT_CMP LIGHT_NODE LIGHT_RAW LIGHT_TH

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-011-photodiode

Catalog #11 in the AruviX sensor line (../README.md), level L1 (GPIO). An ams-OSRAM BPW34S PIN photodiode in photoconductive mode with an LMV7219 comparator and Bourns TC33X threshold trimmer.

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

What it teaches#

An analog quantity squeezed through a comparator: light level becomes a node voltage, the trimmer sets the slicing point, and the raw analog node is brought out on PMOD pin 2 so users can scope the truth behind the digital LIGHT bit (and later feed it to an ADC module).

Design#

BPW34S reverse biased: cathode on 3V3, anode into a 1 MΩ load to GND — photocurrent × 1 MΩ makes the node voltage rise with brightness.
LMV7219M5 (SOT-23-5, push-pull): +in = photodiode node, −in = RV1 wiper (TC33X-2-103E 10 k across 3V3–GND). LIGHT is high above the threshold.
100 Ω series resistors on both module-driven lines: LIGHT (pin 1) and the raw analog node LIGHT_RAW (pin 2). Keep host loading on LIGHT_RAW light — the source impedance is ~1 MΩ.
MPN is BPW34S (the SMD variant matching the Osram_BPW34S-SMD footprint); 100 nF comparator decoupling.

PMOD pin	1	2	3	4	5	6	7	8	9	10	11	12
Net	LIGHT	LIGHT_RAW	NC	NC	GND	3V3	NC	NC	NC	NC	GND	3V3

Regenerate#

python3 generate_design.py

Remaining for release#

[ ] PCB layout (20 × 25 mm outline, diode clear of shadowing parts), DRC
[ ] hdl/: light-edge events + hysteresis-in-time, testbench, ECP5 demo
[ ] BOM export and availability check, design-review checklist