i2c: example for PCA9685 servo driver

Signed-off-by: deadprogram <ron@hybridgroup.com>

examples/firmata_pca9685.go

@@ -0,0 +1,45 @@
+// +build example
+//
+// Do not build by default.
+
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"gobot.io/x/gobot"
+	"gobot.io/x/gobot/drivers/gpio"
+	"gobot.io/x/gobot/drivers/i2c"
+	"gobot.io/x/gobot/platforms/firmata"
+)
+
+func main() {
+	firmataAdaptor := firmata.NewAdaptor("/dev/ttyACM0")
+	pca9685 := i2c.NewPCA9685Driver(firmataAdaptor)
+	servo := gpio.NewServoDriver(pca9685, "15")
+
+	work := func() {
+		pca9685.SetPWMFreq(60)
+
+		for i := 10; i < 150; i += 10 {
+			fmt.Println("Turning", i)
+			servo.Move(uint8(i))
+			time.Sleep(1 * time.Second)
+		}
+
+		for i := 150; i > 10; i -= 10 {
+			fmt.Println("Turning", i)
+			servo.Move(uint8(i))
+			time.Sleep(1 * time.Second)
+		}
+	}
+
+	robot := gobot.NewRobot("servoBot",
+		[]gobot.Connection{firmataAdaptor},
+		[]gobot.Device{pca9685, servo},
+		work,
+	)
+
+	robot.Start()
+}