Gobot: Controlling LEDs connected to an Arduino over Firmata using a PS3 DualShock 3 controller.

dualshock3-firmata-leds.go

package main

import (
	"fmt"

	"github.com/hybridgroup/gobot"
	"github.com/hybridgroup/gobot-firmata"
	"github.com/hybridgroup/gobot-gpio"
	"github.com/hybridgroup/gobot-joystick"
)

func main() {
	firmata := new(gobotFirmata.FirmataAdaptor)

	firmata.Name = "firmata"
	firmata.Port = "/dev/tty.usbmodem1411"

	joystickAdaptor := new(gobotJoystick.JoystickAdaptor)
	joystickAdaptor.Name = "ps3 adaptor"

	// Config for the PS3 controller downloaded from
	// https://github.com/hybridgroup/gobot-joystick/raw/master/configs/dualshock3.json
	//
	joystickAdaptor.Params = map[string]interface{}{
		"config": "./dualshock3.json",
	}

	joystick := gobotJoystick.NewJoystick(joystickAdaptor)
	joystick.Name = "ps3 joystick"

	green := gobotGPIO.NewLed(firmata)
	green.Pin = "11"

	red1 := gobotGPIO.NewLed(firmata)
	red1.Pin = "10"

	red2 := gobotGPIO.NewLed(firmata)
	red2.Pin = "9"

	red3 := gobotGPIO.NewLed(firmata)
	red3.Pin = "6"

	red4 := gobotGPIO.NewLed(firmata)
	red4.Pin = "5"

	red5 := gobotGPIO.NewLed(firmata)
	red5.Pin = "3"

	work := func() {
		// The digital buttons have a <name>_press event
		gobot.On(joystick.Events["triangle_press"], func(interface{}) {
			fmt.Println("triangle_press")
			green.Toggle()
		})

		// The digital buttons also have a <name>_release event
		gobot.On(joystick.Events["up_release"], func(interface{}) {
			fmt.Println("up_release")
		})

		// The data interface contains values between -32767 and 32767
		gobot.On(joystick.Events["left_x"], func(data interface{}) {
			// Use type assertion to make sure that we have a value of type int16
			v := data.(int16)

			// Ignore values of 5k and below
			// (garbage precision between -1500 and 1500)
			if v > 5000 && v < 10000 {
				fmt.Println("*    ", v)
				red1.On()
				red2.Off()
				red3.Off()
				red4.Off()
				red5.Off()
			} else if v > 10000 && v < 15000 {
				fmt.Println("**   ", v)
				red1.On()
				red2.On()
				red3.Off()
				red4.Off()
				red5.Off()
			} else if v > 15000 && v < 20000 {
				fmt.Println("***  ", v)
				red1.On()
				red2.On()
				red3.On()
				red4.Off()
				red5.Off()
			} else if v > 20000 && v < 25000 {
				fmt.Println("**** ", v)
				red1.On()
				red2.On()
				red3.On()
				red4.On()
				red5.Off()
			} else if v > 25000 {
				fmt.Println("*****", v)
				red1.On()
				red2.On()
				red3.On()
				red4.On()
				red5.On()
			} else {
				red1.Off()
				red2.Off()
				red3.Off()
				red4.Off()
				red5.Off()
			}
		})
	}

	robot := gobot.Robot{
		Connections: []gobot.Connection{firmata, joystickAdaptor},
		Devices:     []gobot.Device{joystick},
		Work:        work,
	}

	robot.Start()
}

Issues

I’m seeing 100% CPU usage for some reason, still not sure why though.
I was unable to pinpoint the problem using pprof.
My current theory is that the problem lies somewhere in the usage of SDL.

EDIT: This has now been fixed.

Breadboard

I replaced the leftmost red LED with a green one for this experiment.