A Go package for controlling Lego Mindstorms NXT 2.0
Either install it from the command-line:
$ go install github.com/tonyheupel/go-nxtor add as a dependency in your code files:
import "github.com/tonyheupel/go-nxt"$ go getThe most basic usage can be done using the NXT class by connecting your NXT 2.0 brick over Bluetooth.
There are two main ways to interact with an NXT instance:
- Traditional method calls on the NXT instance, checking for errors
- Interacting with the CommandChannel on the NXT directly.
Interacting with the channels gives you lower-level access and requires a little more work, but if you prefer using channels as your communication paradigm, it's there for you. The NXT commands are all defined as Command structs and can be passed around, so if you are managing multiple bots at once and want to issue the same command to multiple bots, this approach may make more sense.
The example below has one method that first uses the more traditional style interaction, and the second uses channels. They should produce the same output and have the same effect on the bot.
The brick is connected at /dev/tty.NXT-DevB.
package main
import (
"fmt"
"github.com/tonyheupel/go-nxt"
"time"
)
func main() {
n := nxt.NewNXT("heupel-home-bot", "/dev/tty.NXT-DevB")
fmt.Println(n)
err := n.Connect()
if err != nil {
fmt.Println("Could not connect:", err)
return
}
fmt.Println("Connected!")
// Use a more traditional-looking method/check-for-error style
methodStyle(n)
// Pause in between styles to ensure the old commands are done executing
time.Sleep(2 * time.Second)
// Use the raw channels style
channelStyle(n)
n.Disconnect()
}
func methodStyle(n *nxt.NXT) {
// Normally use StartProgram but we want to see the name of the running program
// so we need to wait
startProgramReply, err := n.StartProgramSync("DREW.rxe")
if err != nil {
fmt.Println("Error starting a program:", err)
}
fmt.Println("Reply from StartProgram:", startProgramReply)
runningProgram, err := n.GetCurrentProgramName()
if err != nil {
fmt.Println("Error getting current program name:", err)
} else {
fmt.Println("Current running program:", runningProgram)
}
time.Sleep(3 * time.Second) // Wait 3 seconds before trying to stop
fmt.Println("Stopping running program...")
_, err = n.StopProgramSync()
if err != nil {
fmt.Println("Error stopping the running program:", err)
}
batteryMillivolts, err := n.GetBatteryLevelMillivolts()
if err != nil {
fmt.Println("Error getting the battery level:", err)
} else {
fmt.Println("Battery level (mv):", batteryMillivolts)
}
}
func channelStyle(n *nxt.NXT) {
// All reply messages will be sent to this channel
reply := make(chan *nxt.ReplyTelegram)
// Normally would pass in nil for the reply channel and not wait,
//but we want to see the name of the running program so we need to wait
n.CommandChannel <- nxt.StartProgram("DREW.rxe", reply)
fmt.Println("Reply from StartProgram:", <-reply)
n.CommandChannel <- nxt.GetCurrentProgramName(reply)
runningProgramReply := nxt.ParseGetCurrentProgramNameReply(<-reply)
fmt.Println("Current running program:", runningProgramReply.Filename)
time.Sleep(3 * time.Second) // Wait 3 seconds before trying to stop
fmt.Println("Stopping running program...")
n.CommandChannel <- nxt.StopProgram(reply)
stopProgramReply := <-reply
if stopProgramReply.IsSuccess() {
fmt.Println("Stopped running program successfully!")
} else {
fmt.Println("Was unable to stop the program.")
}
n.CommandChannel <- nxt.GetBatteryLevel(reply)
batteryLevelReply := nxt.ParseGetBatteryLevelReply(<-reply)
if batteryLevelReply.IsSuccess() {
fmt.Println("Battery level (mv):", batteryLevelReply.BatteryLevelMillivolts)
} else {
fmt.Println("Was unable to get the current battery level")
}
}