mirror of
https://github.com/eddyem/eddys_snippets.git
synced 2025-12-06 02:35:12 +03:00
159 lines
5.4 KiB
Markdown
159 lines
5.4 KiB
Markdown
Reading information from different T/P/H sensors
|
|
================================================
|
|
|
|
Supported sensors: AHT10, AHT15, AHT21b, BMP180, BMP280, BME280, SHT3x, SI7005
|
|
|
|
|
|
|
|
|
|
| Sensor | Precision H/T/P | Address | Max speed | Comment |
|
|
|---------|-----------------|---------------|-----------|---------|
|
|
| AHT10 | 2%/0.3°/- | 0x38/0x39 | 400k | ADDR selects lowest address bit |
|
|
| AHT15 | 2%/0.3°/- | 0x38 | 400k | what is the difference from AHT10? |
|
|
| AHT21b | 3%/0.5°/- | 0x38 | 400k | |
|
|
| BMP180 | -/1°/12Pa | 0x77 | 3.4M | could also works by SPI |
|
|
| BME280 | 3%/1°/0.2Pa | 0x76/77 | 3.4M | SDO allows to select lowest I2C address bit; supports SPI |
|
|
| SHT30 | 3%/0.3°/- | 0x44/0x45 | 1M | SHT31 have higher humidity precision (2%); ADDR selects address lowest bit; hav ALERT pin |
|
|
| SI7005 | 4.5%/1°/- | 0x40 | 400k | ~CS can select sensor if several are on bus |
|
|
-------------------------------------------------------------------
|
|
|
|
|
|
## Install library
|
|
|
|
1. Download: `git clone` or other way.
|
|
2. Create building directory: `mkdir mk`. Go into it: `cd mk`.
|
|
3. Run `cmake`: `cmake ..`.
|
|
4. Build and install: `make && su -c "make install"`.
|
|
|
|
### Cmake options
|
|
|
|
Marked options are ON by default:
|
|
|
|
- [ ] DEBUG - compile in debug mode;
|
|
- [x] EXAMPLES - build also examples (they won't be installed, you can use them just in build dir).
|
|
|
|
## How to use
|
|
|
|
After installing library you can use it including `i2csensorsPTH.h` into your code and linking with `-l i2csensorsPTH`.
|
|
Also you can use `pkg-config` after installing library:
|
|
|
|
```
|
|
pkg-config --libs --cflags i2csensorsPTH
|
|
|
|
```
|
|
|
|
|
|
### Base types
|
|
|
|
#### `sensor_status_t`
|
|
|
|
Status of given sensor. `SENS_NOTINIT` means that you should init device; also if you get `SENS_ERR` you should try to reinit it.
|
|
Receiving error on init function means that there's troubles on the bus or with sensor.
|
|
|
|
```
|
|
typedef enum{
|
|
SENS_NOTINIT, // wasn't inited
|
|
SENS_BUSY, // measurement in progress
|
|
SENS_ERR, // error occured
|
|
SENS_RELAX, // do nothing
|
|
SENS_RDY, // data ready - can get it
|
|
} sensor_status_t;
|
|
```
|
|
|
|
#### `sensor_props_t`
|
|
|
|
Properties: if the corresponding field sets, the device have this ability. `flags` allows to use all together as bit fields.
|
|
|
|
```
|
|
typedef union{
|
|
struct{
|
|
uint8_t T : 1; // can temperature (degC)
|
|
uint8_t H : 1; // can humidity (percent)
|
|
uint8_t P : 1; // can pressure (hPa)
|
|
uint8_t htr : 1; // have heater
|
|
};
|
|
uint32_t flags;
|
|
} sensor_props_t;
|
|
```
|
|
|
|
#### `sensor_data_t`
|
|
|
|
Gathered data. The fields that are zeroed in sensor's properties are undefined.
|
|
|
|
```
|
|
typedef struct{
|
|
double T; // temperature, degC
|
|
double H; // humidity, percents
|
|
double P; // pressure, hPa
|
|
} sensor_data_t;
|
|
```
|
|
|
|
### Functions
|
|
|
|
#### `int sensors_open(const char *dev)`
|
|
|
|
Open I2C device by path `dev`. Returns `TRUE` if all OK.
|
|
|
|
#### `void sensors_close()`
|
|
|
|
Close I2C device.
|
|
|
|
#### `char *sensors_list()`
|
|
|
|
Returns allocated string with comma-separated names of all supported sensors. Don't forget to `free` it later.
|
|
|
|
#### `sensor_t* sensor_new(const char *name)`
|
|
|
|
Search `name` in list of supported sensors and, if found, returns pointer to sensors structure. Returns `NULL` if sensor not failed or some error oqqured.
|
|
|
|
#### `void sensor_delete(sensor_t **s)`
|
|
|
|
Delete all memory, allocated for given sensor.
|
|
|
|
#### `sensor_props_t sensor_properties(sensor_t *s)`
|
|
|
|
Allows to check sensor's properties.
|
|
|
|
#### `int sensor_init(sensor_t *s, uint8_t address)`
|
|
|
|
Try to find given sensor on the bus and run initial procedures (like calibration and so on). The `address` argument shoul be zero to use default I2C address or non-zero for custom.
|
|
Returns `TRUE` if all OK.
|
|
|
|
#### `int sensor_heater(sensor_t *s, int on)`
|
|
|
|
Turn on (`on == 1`) or off (`on == 0`) sensor's heater (if sensor supported it). Returns `FALSE` if sensor don't support heater or some error occured during operations.
|
|
|
|
#### `int sensor_start(sensor_t *s)`
|
|
|
|
Start measurement process. While measuring, you should poll sensor until data would be ready (or you get timeout error).
|
|
|
|
#### `sensor_status_t sensor_process(sensor_t *s)`
|
|
|
|
Polling sensor and gathering all data in simple finite-state machine. Checks if sensor is still busy and asks for data portion on each measuring stage.
|
|
Returns current sensor's state. If you get `SENS_RDY`, you can ask for data.
|
|
|
|
#### `int sensor_getdata(sensor_t *s, sensor_data_t *d)`
|
|
|
|
Get data into your variable `d`. Returns `FALSE` if data isn't ready (e.g. you didn't run `start` or sensor is still measuring).
|
|
|
|
### I2C functions
|
|
|
|
Of course, you can wish to work with I2C directly (e.g. to switch multiplexer's channel and so on), so here are some usefull functions.
|
|
|
|
#### `int sensor_writeI2C(uint8_t addr, uint8_t *data, int len)`
|
|
|
|
Write `data` array with len of `len` bytes with device address `addr`. Returns `FALSE` if failed.
|
|
|
|
#### `int sensor_readI2C(uint8_t addr, uint8_t *data, int len)`
|
|
|
|
Read `len` bytes of `data` from address `addr`. Returns `FALSE` if failed.
|
|
|
|
#### `int sensor_readI2Cregs(uint8_t addr, uint8_t regaddr, uint16_t N, uint8_t *data)`
|
|
|
|
Read content of `N` 8-bit registers starting from `regaddr` to array `data`. Returns `FALSE` if failed.
|
|
|
|
#### `int sensor_writeI2Creg(uint8_t addr, uint8_t regaddr, uint8_t data)`
|
|
|
|
Write `data` to single register `regaddr`. Returns `FALSE` if failed.
|
|
|