co2mini

main.go

package main

import (
	"fmt"
	"log"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/zserge/hid"
)

const (
	vendorID = "04d9:a052"
	co2op    = 0x50
)

var (
	key = []byte{0x86, 0x41, 0xc9, 0xa8, 0x7f, 0x41, 0x3c, 0xac}
)

func monitor(device hid.Device) {
	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)

	if err := device.Open(); err != nil {
		log.Fatal(err)
	}
	defer device.Close()

	if err := device.SetReport(0, key); err != nil {
		log.Fatal(err)
	}

	for {
		select {
		case <-sigs:
			return
		default:
			buf, err := device.Read(-1, 3*time.Second)
			if err != nil || len(buf) == 0 {
				continue
			}
			val := int(buf[1])<<8 | int(buf[2])
			switch buf[0] {
			case co2op:
				fmt.Printf("co2\t%d\t%d\n", val, time.Now().Unix())
				return
			}
		}
	}
}

func main() {
	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)

	hid.UsbWalk(func(device hid.Device) {
		info := device.Info()
		id := fmt.Sprintf("%04x:%04x", info.Vendor, info.Product)
		if id != vendorID {
			return
		}
		monitor(device)
	})
}