# ESP32 GP2Y Dust Sensor

## Install

Designed to be used as an `esp-idf component`. Suggested usage is with  `git submodule`

```
git submodule add https://git.oit.cloud/morgan/esp32-gp2y.git components/esp32-gp2y/
git submodule update --init
```

## API

### `typedef gp2y_cfg_t`
`float K` Sensitivity. Default: 0.5
`float offset_voltage` Voltage level at 0ug/m3 dust. Defaults to 0.6v, dynamically lowers.
`int8_t pin_led` Pin to pulse LED on.
`adc1_channel_t adc_channel` ADC channel to read on. See IDF Guide to get pin to channel reference.
`adc_unit_t adc_unit` ADC unit to read on.

### `int32_t gp2y_read(gp2y_cfg_t *cfg, uint8_t samples)`
Passing a pointer to `gp2y_cfg_t` and number of samples to take. 100 is a good starting point.


## Example
```
#include <stdio.h>
#include <unistd.h>
#include "driver/gpio.h"
#include "driver/adc.h"
#include "esp32-gp2y.h"

#define PIN_LED         5

void app_main() {
    gp2y_cfg_t gp2y_cfg = GP2Y_DEFAULT_CFG;
    gp2y_cfg.adc_channel = channel;
    gp2y_cfg.pin_led = PIN_LED;

    gpio_config_t io_conf;
    io_conf.intr_type = GPIO_INTR_DISABLE;
    io_conf.mode = GPIO_MODE_OUTPUT;
    io_conf.pin_bit_mask = (1ULL<<gp2y_cfg.pin_led);
    io_conf.pull_down_en = 1;
    io_conf.pull_up_en = 0;
    gpio_config(&io_conf);

    adc1_config_channel_atten(gp2y_cfg.adc_channel, ADC_ATTEN_DB_11);

    while (1) {
      printf("aqi: %dug/m3\n", gp2y_read(&gp2y_cfg, 100));
      vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
}
```