samples: universal blinker example

samples/.gitignore

@@ -20,5 +20,6 @@ servobbb
 servoblaster
 simpleblinker
 tmp006
+universalblinker
 us020
 watersensor

samples/universalblinker.go

@@ -0,0 +1,59 @@
+// +build ignore
+
+// Universal LED blinker, works OOTB on a RPi / BBB.
+
+package main
+
+import (
+	"flag"
+	"os"
+	"os/signal"
+	"time"
+
+	"github.com/kidoman/embd"
+	_ "github.com/kidoman/embd/host/all"
+)
+
+func main() {
+	flag.Parse()
+
+	panicIf(embd.InitLED())
+	defer embd.CloseLED()
+
+	led, err := embd.NewLED(ledToBlink())
+	panicIf(err)
+	defer led.Off()
+
+	quit := make(chan os.Signal, 1)
+	signal.Notify(quit, os.Interrupt, os.Kill)
+	defer signal.Stop(quit)
+
+	for {
+		select {
+		case <-time.After(250 * time.Millisecond):
+			panicIf(led.Toggle())
+		case <-quit:
+			return
+		}
+	}
+}
+
+func ledToBlink() string {
+	host, _, err := embd.DetectHost()
+	panicIf(err)
+
+	switch host {
+	case embd.HostRPi:
+		return "LED0"
+	case embd.HostBBB:
+		return "USR3"
+	}
+
+	panic("Unsupported host")
+}
+
+func panicIf(err error) {
+	if err != nil {
+		panic(err)
+	}
+}