Sensirion

All Sensirion sensors use I2C digital interface (some variants support alternate addresses).

MPN Structure

Sensirion MPNs follow this general structure:

[PREFIX][SERIES]-[VARIANT][GRADE]-[REEL]
   │       │        │        │       │
   │       │        │        │       └── Reel option: R2, R4 (tape & reel qty)
   │       │        │        └── Accuracy grade: A, B, F
   │       │        └── Variant code: DIS, AD1B, D, P, etc.
   │       └── Series number (30, 31, 40, 41, 45, etc.)
   └── Family prefix (SHT, STS, SGP, SCD, SFA, SPS, SLF, SDP)

Example Decoding

SHT31-DIS-B
│  │  │   │
│  │  │   └── B = Accuracy grade B
│  │  └── DIS = Digital sensor variant
│  └── 31 = Series 31 (mid-range accuracy)
└── SHT = Humidity & Temperature sensor

SHT40-AD1B-R2
│  │  │  │ │
│  │  │  │ └── R2 = Tape & reel (2000 pcs)
│  │  │  └── B = Accuracy grade B
│  │  └── AD1 = Alternate I2C address variant
│  └── 40 = Series 40 (4th generation)
└── SHT = Humidity & Temperature sensor

SGP40-D-R4
│  │  │ │
│  │  │ └── R4 = Tape & reel (4000 pcs)
│  │  └── D = Standard digital variant
│  └── 40 = Series 40
└── SGP = Gas sensor (VOC)

SLF3S-1300F
│  │  │   │
│  │  │   └── F = Variant identifier
│  │  └── 1300 = Flow range identifier
│  └── 3S = Series/size
└── SLF = Liquid Flow sensor

Variant Codes

Package/Variant Codes

Reel Options

Accuracy Grades

Sensirion sensors come in different accuracy grades. Higher accuracy = tighter tolerance.

Grade Ordering (best to worst): A > B > F

Compatibility Rule: Higher accuracy grades can replace lower grades (A can replace B, B can replace F).

Series Families

SHT Humidity & Temperature Sensors

Compatibility: SHT4x can replace SHT3x (next generation, same function).

Within series: SHT35 > SHT31 > SHT30 (accuracy ordering)

STS Temperature-Only Sensors

Compatibility: STS4x can replace STS3x.

SGP Gas Sensors (VOC)

Compatibility: SGP4x can replace SGP3x (improved performance).

SCD CO2 Sensors

Compatibility: SCD4x can replace SCD3x (miniaturized, same accuracy).

SDP Differential Pressure Sensors

Not interchangeable - different pressure ranges require design consideration.

Supported Component Types

From SensirionHandler.getSupportedTypes():

Set.of(
    ComponentType.SENSOR,              // Generic sensor
    ComponentType.HUMIDITY_SENSOR,     // SHTxx, humidity measurement
    ComponentType.TEMPERATURE_SENSOR,  // SHTxx, STSxx temperature
    ComponentType.PRESSURE_SENSOR,     // SDPxx differential pressure
    ComponentType.SENSOR_FLOW,         // SLFxx liquid flow
    ComponentType.IC                   // SGPxx, SCDxx (complex sensors)
)

Pattern Registration

Package Code Extraction

The handler extracts package codes from the variant portion after the first hyphen:

// Input: SHT31-DIS-B
// After first dash: "DIS-B"
// Package part: "DIS" (before second dash)
// Returns: "DFN" (mapped)

// Input: SHT40-AD1B-R2
// After first dash: "AD1B-R2"
// Package part: "AD1B"
// Returns: "DFN"

Package Code Mappings

Note: Most Sensirion sensors use DFN (Dual Flat No-lead) packaging.

Series Extraction

The handler extracts series by grouping based on prefix patterns:

// Input: SHT31-DIS-B
// Base part: "SHT31" (before first dash)
// Starts with "SHT3" → Returns: "SHT3x"

// Input: SCD40-D-R2
// Base part: "SCD40"
// Starts with "SCD4" → Returns: "SCD4x"

Series Groupings

Replacement Compatibility

Official Replacement Logic

The handler implements isOfficialReplacement() with these rules:

1. Same series: Compatible if accuracy grade allows

   • A can replace B or F
   • B can replace F
   • F cannot replace A or B

2. Cross-series replacements:

   • SHT4x can replace SHT3x (next generation)
   • STS4x can replace STS3x
   • SGP4x can replace SGP3x (improved gas sensor)
   • SCD4x can replace SCD3x (miniaturized CO2)

3. Not interchangeable:

   • SDP3x and SDP8x (different pressure ranges)
   • Different sensor families (SHT cannot replace SGP)

Example MPNs

Handler Implementation Notes

Interface Extraction

// Most Sensirion sensors use I2C
// AD variants indicate alternate I2C address

if (upperMpn.contains("-AD")) return "I2C-ALT"; // Alternate address
return "I2C"; // Default

Accuracy Grade Extraction

// Grade embedded in variant code or as suffix
// SHT31-DIS-B → grade "B"
// SHT40-AD1B → grade "B" (from "1B")

if (upperMpn.contains("-B") || upperMpn.contains("1B")) return "B";
if (upperMpn.contains("-F") || upperMpn.contains("1F")) return "F";
if (upperMpn.contains("-A") || upperMpn.contains("1A")) return "A";

Related Files

• Handler: manufacturers/SensirionHandler.java
• Component types: SENSOR, HUMIDITY_SENSOR, TEMPERATURE_SENSOR, PRESSURE_SENSOR, SENSOR_FLOW, IC

Learnings & Quirks

• All sensors use I2C: Sensirion standardizes on I2C digital interface across all product families
• DFN is dominant: Most sensors use DFN (Dual Flat No-lead) packaging; "P" suffix indicates pin header for development
• Generation upgrades: 4x series generally replaces 3x series with improved specs and smaller footprint
• Accuracy grade hierarchy: A > B > F; higher grades can replace lower but not vice versa
• Dual-function sensors: SHTxx measures both humidity AND temperature; use appropriate ComponentType based on application
• Complex sensors as IC: Gas (SGP), CO2 (SCD), and particulate (SPS) sensors are registered as both SENSOR and IC due to their processing complexity
• AD variants: "AD" in variant code indicates alternate I2C address for multi-sensor configurations
• Reel quantities: R2 = 2000 pcs, R4 = 4000 pcs tape and reel
• Pressure sensors not interchangeable: SDP3x and SDP8x have different pressure ranges; check specs before substitution
• No manufacturer-specific ComponentTypes: Unlike TI/ST handlers, Sensirion uses generic types (HUMIDITY_SENSOR, not HUMIDITY_SENSOR_SENSIRION)