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devices/sen6x/pm.go

55 lines
1.6 KiB
Go

// Copyright 2026 The Periph Authors. All rights reserved.
// Use of this source code is governed under the Apache License, Version 2.0
// that can be found in the LICENSE file.
package sen6x
import "encoding/binary"
// PMNumberConcentrations contains particulate matter measurements in particles/cm³ ("number concentration").
type PMNumberConcentrations struct {
PM05, PM1, PM25, PM4, PM10 *uint16
}
// ReadNumberConcentrationValues reads the current particulate matter concentration
// measurements in particles/cm³ ("number concentration") rather than the more
// conventional μg/m³.
//
// [Dev.GetDataReady] may be used to check if new data is available since the
// last read operation. If no new data is available, the previous values will
// be returned. If no data is available at all (e.g. measurement not running
// for at least one second), all values will be nil.
func (d *Dev) ReadNumberConcentrationValues() (*PMNumberConcentrations, error) {
d.mu.Lock()
defer d.mu.Unlock()
data, err := d.writeAndRead(cmdReadNumberConcentrationValues, nil)
if err != nil {
return nil, err
}
nc := &PMNumberConcentrations{}
if rawPM05 := binary.BigEndian.Uint16(data[0:2]); rawPM05 != 0xffff {
nc.PM05 = ptr(rawPM05)
}
if rawPM1 := binary.BigEndian.Uint16(data[2:4]); rawPM1 != 0xffff {
nc.PM1 = ptr(rawPM1)
}
if rawPM25 := binary.BigEndian.Uint16(data[4:6]); rawPM25 != 0xffff {
nc.PM25 = ptr(rawPM25)
}
if rawPM4 := binary.BigEndian.Uint16(data[6:8]); rawPM4 != 0xffff {
nc.PM4 = ptr(rawPM4)
}
if rawPM10 := binary.BigEndian.Uint16(data[8:10]); rawPM10 != 0xffff {
nc.PM10 = ptr(rawPM10)
}
return nc, nil
}