98 lines
1.4 KiB
Go
98 lines
1.4 KiB
Go
// https://medium.com/coinmonks/iot-tutorial-read-tags-from-a-usb-rfid-reader-with-raspberry-pi-and-node-red-from-scratch-4554836be127
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// nolint: gochecknoglobals, lll, forbidigo
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package main
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import (
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"fmt"
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"log"
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"os"
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)
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const newLine = 40
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var charMap = map[byte]string{
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4: "a",
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5: "b",
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6: "c",
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7: "d",
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8: "e",
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9: "f",
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10: "g",
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11: "h",
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12: "i",
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13: "j",
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14: "k",
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15: "l",
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16: "m",
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17: "n",
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18: "o",
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19: "p",
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20: "q",
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21: "r",
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22: "s",
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23: "t",
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24: "u",
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25: "v",
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26: "w",
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27: "x",
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28: "y",
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29: "z",
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30: "1",
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31: "2",
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32: "3",
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33: "4",
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34: "5",
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35: "6",
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36: "7",
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37: "8",
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38: "9",
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39: "0",
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}
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func main() {
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d, err := os.Open("/dev/hidraw7")
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if err != nil {
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log.Fatal(err)
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}
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id := make(chan string)
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go func() {
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buf := make([]byte, 3)
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rfid := ""
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for {
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// Reading the RFID reader.
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_, err := d.Read(buf)
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if err != nil {
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log.Print(err)
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continue
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}
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// 40 means "\n" and is an indicator that the input is complete.
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// Send the id string to the consumer channel.
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if buf[2] == newLine {
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id <- rfid
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rfid = ""
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continue
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}
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// Check if byte is in the charMap and if its true, append it to the rfid string.
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// It waits till next read and checks for the newline byte.
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c, ok := charMap[buf[2]]
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if ok {
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rfid += c
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}
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}
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}()
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// Wait for an RFID ID and do something with it.
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for {
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rfid := <-id
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fmt.Println(rfid)
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}
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}
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