sgp4x 1.0.0

Rust driver for the Sensirion SGP41 gas sensor with VOC and NOx measurement capabilities.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134

# sgp4x
Platform agnostic Rust device driver for Sensirion SGP4x created based on https://crates.io/crates/sgp40. At the moment, it supports both SGP41 and SGP40 (although NOx will fail for SGP40)

[![Build status][workflow-badge]][workflow]
[![Crates.io Version][crates-io-badge]][crates-io]
[![Crates.io Downloads][crates-io-download-badge]][crates-io-download]
![No Std][no-std-badge]

Platform agnostic Rust driver for Sensirion SGP41 gas sensor using the [`embedded-hal`](https://github.com/japaric/embedded-hal) traits.

## Sensirion SGP4X

Sensirion SGP4X is a low-power accurate gas sensor for air quality applications. The sensor uses I²C interface and measures both VOC (*Total Volatile Organic Compounds*) and NOx (*Nitrogen Oxides*) providing comprehensive air quality monitoring capabilities.

Key features:
- **Dual gas measurement**: VOC and NOx indices
- **Temperature/humidity compensation**: Improved accuracy with environmental data
- **Low power consumption**: Optimized for battery-powered applications  
- **I²C interface**: Simple integration with 0x59 address
- **No-std compatible**: Works in embedded environments
- **Gas index algorithms**: Uses official Sensirion algorithms via gas-index-algorithm crate

Datasheet: <https://www.sensirion.com/file/datasheet_sgp41>

## Usage

### Basic VOC and NOx Measurements

```rust
use linux_embedded_hal as hal;
use hal::{Delay, I2cdev};
use sgp41::Sgp41;

let dev = I2cdev::new("/dev/i2c-1").unwrap();
let mut sensor = Sgp41::new(dev, 0x59, Delay);

// Warm up the sensor (first 45 samples should be discarded)
for _ in 0..45 {
    sensor.measure_voc_index().ok();
}

// Individual measurements
let voc_index = sensor.measure_voc_index()?; // 1-500 (100 = average)
let nox_index = sensor.measure_nox_index()?; // 1-500 (1 = average)

// Combined measurement (more efficient)
let (voc, nox) = sensor.measure_indices()?;
```

### Temperature and Humidity Compensation

```rust
let humidity = 50_u16; // 50% RH  
let temperature = 25_i16; // 25°C

// Compensated measurements
let voc = sensor.measure_voc_index_with_rht(humidity, temperature)?;
let nox = sensor.measure_nox_index_with_rht(humidity, temperature)?;

// Combined compensated measurement
let (voc, nox) = sensor.measure_indices_with_rht(humidity, temperature)?;
```

### Raw Signal Access

```rust
// Individual raw signals
let voc_raw = sensor.measure_raw()?;
let nox_raw = sensor.measure_raw_nox()?;

// Combined raw signals
let (voc_raw, nox_raw) = sensor.measure_raw_signals()?;
```

### SGP41-Specific Features

```rust
// Conditioning (recommended for new sensors)
sensor.execute_conditioning()?;

// Conditioning with VOC reading
sensor.execute_conditioning_with_voc_read()?;
```

## Migration from SGP40

The SGP41 driver maintains API compatibility with SGP40 for VOC measurements:

```rust
// SGP40 code
use sgp40::Sgp40;
let mut sensor = Sgp40::new(i2c, 0x59, delay);
let voc = sensor.measure_voc_index()?;

// SGP41 equivalent  
use sgp41::Sgp41;
let mut sensor = Sgp41::new(i2c, 0x59, delay);
let voc = sensor.measure_voc_index()?; // Same API
let nox = sensor.measure_nox_index()?; // New capability
```

## Examples

- [`main.rs`](examples/main.rs) - Linux example showing all measurement types
- [`nrf52-example`](examples/nrf52-example/) - Embedded no-std example for NRF52

## Development status
The crate is feature complete with full VOC and NOx measurement capabilities.


## License

Licensed under either of

 * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
   http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or
   http://opensource.org/licenses/MIT) at your option.


### Contributing

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall
be dual licensed as above, without any additional terms or conditions.

<!-- Badges -->
[workflow]: https://github.com/mjaakkol/sgp40-rs/actions?query=workflow%3ARust
[workflow-badge]: https://img.shields.io/github/workflow/status/mjaakkol/sgp40-rs/Rust/master
[crates-io]: https://crates.io/crates/sgp41
[crates-io-badge]: https://img.shields.io/crates/v/sgp41.svg?maxAge=3600
[crates-io-download]: https://crates.io/crates/sgp41
[crates-io-download-badge]: https://img.shields.io/crates/d/sgp41.svg?maxAge=3600
[no-std-badge]: https://img.shields.io/badge/no__std-yes-blue