Sensor modules

AXS-004 — Vibration sensor PMOD module

Catalog #4 in the AruviX sensor line, level L1 (GPIO). An SW-420 spring vibration element biased by a 1 MΩ pull-up, RC-filtered, and sliced by an LMV7219 comparator against a Bourns TC33X trimmer threshold, so the host sees clean push-pull pulses per shake.

Level L1 ERC clean DRC clean Fab package 9 components

3D render of the AXS-004 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`
`C2`	100nF 16V X7R	RC filter capacitor (with R2), ~1 ms time constant	`GRM188R71C104KA01D` Murata	`C_0603_1608Metric`
`J1`	PMOD PLUG 2x6	PMOD peripheral plug (Digilent spec 1.2)	not selected generic	`PinHeader_2x06_P2.54mm_Horizontal`
`J2`	SW-420 ELEMENT	SW-420 spring vibration element soldered across two THT pads (non-polarized)	not selected generic	`PinHeader_1x02_P2.54mm_Vertical`
`R1`	1M	Element bias pull-up: node sits high, dips while the spring contact closes	`RC0603FR-071ML` Yageo Datasheet ↗	`R_0603_1608Metric`
`R2`	10k	RC filter series element (with C2) smoothing contact chatter	`RC0603FR-0710KL` Yageo Datasheet ↗	`R_0603_1608Metric`
`R3`	100R	Series protection on the module-driven VIB line	`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 VIB VIB_CMP VIB_ELEM VIB_FILT VIB_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-004-vibration

Catalog #4 in the AruviX sensor line (../README.md), level L1 (GPIO). An SW-420 spring vibration element biased by a 1 MΩ pull-up, RC-filtered, and sliced by an LMV7219 comparator against a Bourns TC33X trimmer threshold, so the host sees clean push-pull pulses per shake.

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

What it teaches#

Turning a noisy mechanical contact into countable events: pulse counting, integration over a time window to grade shake intensity, and (with RV1) what an analog threshold does to event rate.

Design#

The bare SW-420 spring element solders across a generic 1×02 THT pad pair (J2, PinHeader_1x02 footprint used as plain pads; element is non-polarized, MPN TBD).
1 MΩ pull-up biases the element node high; the spring contact pulls it toward GND while vibrating. A 10 kΩ / 100 nF RC (~1 ms) smooths chatter.
LMV7219M5 (SOT-23-5, push-pull): +in = filtered node, −in = RV1 wiper (TC33X-2-103E, 10 k trimmer across 3V3–GND). Output pulses low on vibration and passes a 100 Ω series resistor to PMOD pin 1 (VIB).
The spec's alternative LM393 was skipped: the stock symbol is multi-unit (the shared generator emits unit 1 only) and its open-drain output would need another pull-up. The single, push-pull LMV7219 was the spec's preferred option.
100 nF comparator decoupling.

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

Regenerate#

python3 generate_design.py

Remaining for release#

[ ] PCB layout (20 × 25 mm outline), DRC, fab outputs
[ ] hdl/: pulse counter + leaky integrator, testbench, ECP5 demo
[ ] BOM export, pin the SW-420 element source, design-review checklist