Drive a rover in a square in 2 minutes
If you haven’t read through Learn Viam, we recommend you do so, to get an overview of the Viam platform.
In this guide you’ll write code that makes a rover drive in a square.
You will learn
- How to run SDK code
- How to use the base API to move a rover in a square
Requirements
You don’t need to buy or own any hardware to complete this tutorial. You only need the following:
- A Linux, macOS or Windows computer that can run SDK code.
- A borrowed Viam Rover, your own Viam Rover, or another mobile robot. You can use Try Viam to borrow a rover online at no cost which is already configured with all the components you need. If you have your own rover on hand, whether it’s a Viam rover or not, these instructions work for any wheeled robot that can be configured as a base component.
Instructions
Follow these steps to get your rover ready inside the Viam app and write code to control it:
Important
If you are using your own robot for this tutorial instead of borrowing one, be sure to install viam-server on it, and connect and configure its hardware before proceeding with this tutorial.
Now that you have connected the rover to Viam with the SDK, you can write code to move the rover in a square: The base is responsible for controlling the motors attached to the base of the rover.
Ensure that the Then paste this snippet above your Next, remove all the code in the On the Try Viam rovers, the default base name is If you have a borrowed Try Viam rover, navigate to your machine’s CONTROL tab, which allows you to interact with your machine’s resources. Click on one of the camera panels and toggle the camera stream on so you can observe the rover’s movements. Then run your code and watch your rover move in a square. The base is responsible for controlling the motors attached to the base of the rover.
Ensure that the Then paste this snippet above your Next, remove all the code in the Also remove any unused imports. On the Try Viam rovers, the default base name is If you have a borrowed Try Viam rover, navigate to your machine’s CONTROL tab, which allows you to interact with your machine’s resources. Click on one of the camera panels and toggle the camera stream on so you can observe the rover’s movements. Then run your code and watch your rover move in a square. Above the On the Try Viam rovers, the default base name is Underneath the Next, register a listener on the button you obtain from the Your main function should now look like this: Save your code and refresh the browser page.
When the connection to the rover is established, the If you have a borrowed Try Viam rover, open a tab and navigate to your machine’s CONTROL tab, which allows you to interact with your rover’s resources. Click on one of the camera panels and toggle the camera stream on so you can observe the rover’s movements. Go back to the Add a new file to your application in This code creates a screen with a singular centered button that, when pressed, calls on the Then, replace the contents of This imports the To navigate to the base screen, save your code and launch your simulator.
Navigate to the robot screen of a (live) machine with a base resource configured, and see the resources displayed like the following: Then, click on the base to display the base screen.
You may need to scroll to the bottom of the list of resources. Click on the button to move your rover in a square: The base is responsible for controlling the motors attached to the base of the rover.
Ensure that the Additionally, add the following namespaces under your imports: Then paste this snippet above your main() function, it will move any base passed to it in a square: Next, remove all the code in the On the Try Viam rovers, the default base name is If you have a borrowed Try Viam rover, navigate to your machine’s CONTROL tab, which allows you to interact with your machine’s resources. Click on one of the camera panels and toggle the camera stream on so you can observe the rover’s movements. Then run your code and watch your rover move in a square. If you are interested to learn about what other commands you can give to a base, see the standardized base API for a full list of available API methods.
Step 4: Drive a rover in a square
Base class is being imported:
from viam.components.base import Base
main() function, it will move any base passed to it in a square:
async def moveInSquare(base):
for _ in range(4):
# moves the rover forward 500mm at 500mm/s
await base.move_straight(velocity=500, distance=500)
print("move straight")
# spins the rover 90 degrees at 100 degrees per second
await base.spin(velocity=100, angle=90)
print("spin 90 degrees")
main() function between where the machine connection is established and closed and instead initialize your base and invoke the moveInSquare() function.viam_base.
If you have a different base name, update the name in your code.
async def main():
machine = await connect()
# Get the base component from the rover
roverBase = Base.from_robot(machine, 'viam_base')
# Move the rover in a square
await moveInSquare(roverBase)
await machine.close()
Base class is being imported:
import (
// Be sure to keep all of the other imported libraries
"go.viam.com/rdk/components/base"
)
main() function, it will move any base passed to it in a square:
func moveInSquare(ctx context.Context, base base.Base, logger logging.Logger) {
for i := 0; i < 4; i++ {
// moves the rover forward 600mm at 500mm/s
base.MoveStraight(ctx, 600, 500.0, nil)
logger.Info("move straight")
// spins the rover 90 degrees at 100 degrees per second
base.Spin(ctx, 90, 100.0, nil)
logger.Info("spin 90 degrees")
}
}
main() function after the machine connection is established and instead initialize your base and invoke the moveInSquare() function.viam_base.
If you have a different base name, update the name in your code.
func main() {
logger := logging.NewLogger("client")
machine, err := client.New(
context.Background(),
"ADDRESS FROM THE VIAM APP",
logger,
client.WithDialOptions(rpc.WithEntityCredentials(
/* Replace "<API-KEY-ID>" (including brackets) with your machine's api key id */
"<API-KEY-ID>",
rpc.Credentials{
Type: rpc.CredentialsTypeAPIKey,
/* Replace "<API-KEY>" (including brackets) with your machine's api key */
Payload: "<API-KEY>",
})),
)
if err != nil {
logger.Fatal(err)
}
defer machine.Close(context.Background())
// Get the base from the rover
roverBase, err := base.FromRobot(machine, "viam_base")
if err != nil {
logger.Fatalf("cannot get base: %v", err)
}
// Move the rover in a square
moveInSquare(context.Background(), roverBase, logger)
}
main function, add the following function that initializes your rover base client and drives it in a square.viam_base.
If you have a different base name, update the name in your code.
// This function moves a base component in a square.
async function moveInSquare(client: VIAM.RobotClient) {
// Replace with the name of the base on your machine.
const name = "viam_base";
const baseClient = new VIAM.BaseClient(client, name);
try {
button().disabled = true;
for (let i = 0; i < 4; i++) {
console.log("move straight");
await baseClient.moveStraight(500, 500);
console.log("spin 90 degrees");
await baseClient.spin(90, 100);
}
} finally {
button().disabled = false;
}
}
moveInSquare function, add this button function which gets the main-button button from the page loaded from index.html:
// This function gets the button element
function button() {
return <HTMLButtonElement>document.getElementById("main-button");
}
button function and make it invoke the moveInSquare function.
Place this code after the rover connection code:
button().onclick = async () => {
await moveInSquare(machine);
};
button().disabled = false;
async function main() {
const host = "ADDRESS_FROM_VIAM_APP";
const machine = await VIAM.createRobotClient({
host,
credential: {
type: "api-key",
// Replace "<API-KEY>" (including brackets) with your machine's API key
payload: "<API-KEY>",
},
// Replace "<API-KEY-ID>" (including brackets) with your machine's API key ID
authEntity: "<API-KEY-ID>",
signalingAddress: "https://app.viam.com:443",
});
button().onclick = async () => {
await moveInSquare(machine);
};
button().disabled = false;
}
Click me to drive rover in square button will become enabled.Click me to drive rover in square button and click the button to run your code and switch back to the CONTROL tab to watch your rover move in a square.
/// This is the BaseScreen, which allows us to control a Base.
import 'package:flutter/material.dart';
import 'package:viam_sdk/viam_sdk.dart';
import 'package:viam_sdk/widgets.dart';
class BaseScreen extends StatelessWidget {
final Base base;
const BaseScreen(this.base, {super.key});
Future<void> moveSquare() async {
for (var i=0; i<4; i++) {
await base.moveStraight(500, 500);
await base.spin(90, 100);
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text(base.name)),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
ElevatedButton(
onPressed: moveSquare,
child: const Text('Move Base in Square'),
),
]))
,);}}
moveSquare() method to drive the base in a square.
/// This is the screen that shows the resources available on a robot (or smart machine).
/// It takes in a Viam app client instance, as well as a robot client.
/// It then uses the Viam client instance to create a connection to that robot client.
/// Once the connection is established, you can view the resources available
/// and send commands to them.
import 'package:flutter/material.dart';
import 'package:viam_sdk/protos/app/app.dart';
import 'package:viam_sdk/viam_sdk.dart';
import 'base_screen.dart';
class RobotScreen extends StatefulWidget {
final Viam _viam;
final Robot robot;
const RobotScreen(this._viam, this.robot, {super.key});
@override
State<RobotScreen> createState() => _RobotScreenState();
}
class _RobotScreenState extends State<RobotScreen> {
/// Similar to previous screens, start with [_isLoading] to true.
bool _isLoading = true;
/// This is the [RobotClient], which allows you to access
/// all the resources of a Viam Smart Machine.
/// This differs from the [Robot] provided to us in the widget constructor
/// in that the [RobotClient] contains a direct connection to the Smart Machine
/// and its resources. The [Robot] object simply contains information about
/// the Smart Machine, but is not actually connected to the machine itself.
///
/// This is initialized late because it requires an asynchronous
/// network call to establish the connection.
late RobotClient client;
@override
void initState() {
super.initState();
// Call our own _initState method to initialize our state.
_initState();
}
@override
void dispose() {
// You should always close the [RobotClient] to free up resources.
// Calling [RobotClient.close] will clean up any tasks and
// resources created by Viam.
if (_isLoading == false) {
client.close();
}
super.dispose();
}
/// This method will get called when the widget initializes its state.
/// It exists outside the overridden [initState] function since it's async.
Future<void> _initState() async {
// Using the authenticated [Viam] the received as a parameter,
// the app can obtain a connection to the Robot.
// There is a helpful convenience method on the [Viam] instance for this.
final robotClient = await widget._viam.getRobotClient(widget.robot);
setState(() {
client = robotClient;
_isLoading = false;
});
}
/// A computed variable that returns the available [ResourceName]s of
/// this robot in an alphabetically sorted list.
List<ResourceName> get _sortedResourceNames {
return client.resourceNames..sort((a, b) => a.name.compareTo(b.name));
}
bool _isNavigable(ResourceName rn) {
if (rn.subtype == Base.subtype.resourceSubtype) {
return true;
}
return false;
}
void _navigate(ResourceName rn) {
if (rn.subtype == Base.subtype.resourceSubtype) {
final base = Base.fromRobot(client, rn.name);
Navigator.of(context).push(MaterialPageRoute(builder: (_) => BaseScreen(base)));
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text(widget.robot.name)),
body: _isLoading
? const Center(child: CircularProgressIndicator.adaptive())
: ListView.builder(
itemCount: client.resourceNames.length,
itemBuilder: (_, index) {
final resourceName = _sortedResourceNames[index];
return ListTile(
title: Text(resourceName.name),
subtitle: Text(
'${resourceName.namespace}:${resourceName.type}:${resourceName.subtype}'),
onTap: () => _navigate(resourceName),
trailing: _isNavigable(resourceName) ? Icon(Icons.chevron_right) : SizedBox.shrink(),
);
}));
}
}
Base class is being imported:
#include <viam/sdk/components/base.hpp>
using namespace viam::sdk;
using std::cerr;
using std::cout;
using std::endl;
void move_in_square(std::shared_ptr<viam::sdk::Base> base) {
for (int i = 0; i < 4; ++i) {
cout << "Move straight" << endl;
// Move the base forward 600mm at 500mm/s
base->move_straight(500, 500);
cout << "Spin" << endl;
// Spin the base by 90 degree at 100 degrees per second
base->spin(90, 100);
}
}
main() function after the machine connection is established, and instead initialize your base and invoke the moveInSquare() function.viam_base.
If you have a different base name, update the name in your code.
int main() {
std::string host("ADDRESS FROM THE VIAM APP");
DialOptions dial_opts;
// Replace "<API-KEY-ID>" with your machine's api key ID
dial_opts.set_entity(std::string("<API-KEY-ID>"));
// Replace "<API-KEY>" with your machine's api key
Credentials credentials("api-key", "<API-KEY>");
dial_opts.set_credentials(credentials);
boost::optional<DialOptions> opts(dial_opts);
Options options(0, opts);
auto machine = RobotClient::at_address(host, options);
std::cout << "Resources:\n";
for (const Name& resource : machine->resource_names()) {
std::cout << "\t" << resource << "\n";
}
std::string base_name("viam_base");
cout << "Getting base: " << base_name << endl;
std::shared_ptr<Base> base;
try {
base = machine->resource_by_name<Base>(base_name);
move_in_square(base);
} catch (const std::exception& e) {
cerr << "Failed to find " << base_name << ". Exiting." << endl;
throw;
}
return EXIT_SUCCESS;
}
Tip
Complete code
This is the complete code for the tutorial:
import asyncio
from viam.components.base import Base
from viam.robot.client import RobotClient
from viam.rpc.dial import Credentials, DialOptions
async def connect():
opts = RobotClient.Options.with_api_key(
# Replace "<API-KEY>" (including brackets) with your machine's API key
api_key='<API-KEY>',
# Replace "<API-KEY-ID>" (including brackets) with your machine's
# API key ID
api_key_id='<API-KEY-ID>'
)
return await RobotClient.at_address('ADDRESS FROM THE VIAM APP', opts)
async def moveInSquare(base):
for _ in range(4):
# moves the rover forward 500mm at 500mm/s
await base.move_straight(velocity=500, distance=500)
print("move straight")
# spins the rover 90 degrees at 100 degrees per second
await base.spin(velocity=100, angle=90)
print("spin 90 degrees")
async def main():
machine = await connect()
roverBase = Base.from_robot(machine, 'viam_base')
# Move the rover in a square
await moveInSquare(roverBase)
await machine.close()
if __name__ == '__main__':
asyncio.run(main())
package main
import (
"context"
"go.viam.com/rdk/components/base"
"go.viam.com/rdk/logging"
"go.viam.com/rdk/robot/client"
"go.viam.com/rdk/utils")
func moveInSquare(ctx context.Context, base base.Base, logger logging.Logger) {
for i := 0; i < 4; i++ {
// moves the rover forward 600mm at 500mm/s
base.MoveStraight(ctx, 600, 500.0, nil)
logger.Info("move straight")
// spins the rover 90 degrees at 100 degrees per second
base.Spin(ctx, 90, 100.0, nil)
logger.Info("spin 90 degrees")
}
}
func main() {
logger := logging.NewLogger("client")
machine, err := client.New(
context.Background(),
"ADDRESS FROM THE VIAM APP",
logger,
client.WithDialOptions(utils.WithEntityCredentials(
// Replace "<API-KEY-ID>" (including brackets) with your machine's API key ID
"<API-KEY-ID>",
utils.Credentials{
Type: utils.CredentialsTypeAPIKey,
// Replace "<API-KEY>" (including brackets) with your machine's API key
Payload: "<API-KEY>",
})),
)
if err != nil {
logger.Fatal(err)
}
defer machine.Close(context.Background())
// Get the base from the rover
roverBase, err := base.FromRobot(machine, "viam_base")
if err != nil {
logger.Fatalf("cannot get base: %v", err)
}
// Move the rover in a square
moveInSquare(context.Background(), roverBase, logger)
}
{
"name": "test-rover",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "esbuild ./main.ts --bundle --outfile=static/main.js --servedir=static",
"test": "echo \"Error: no test specified\" && exit 1"
},
"author": "Viam Docs Team",
"license": "ISC",
"devDependencies": {
"esbuild": "*"
},
"dependencies": {
"@viamrobotics/sdk": "*"
}
}
<!doctype html>
<html>
<head>
<title>Drive a Rover</title>
<link rel="icon" href="favicon.ico" />
</head>
<body>
<div id="main">
<h1>Drive a rover in a square</h1>
<p>
We recommend you open the developer tools in your browser to see logs.
</p>
<p>
Also open a second window with the
<a href="https://app.viam.com">Viam app</a> and navigate to your rover's
<b>CONTROL</b> tab, which allows you to interact with your rover's
resources. Click on one of the camera panels and toggle the camera
stream on so you can observe the rover's movements.
</p>
<button id="main-button" disabled="true">
Click me to drive rover in square
</button>
</div>
<script type="module" src="main.js"></script>
</body>
</html>
// This code must be run in a browser environment.
import * as VIAM from "@viamrobotics/sdk";
// This function moves a base component in a square.
async function moveInSquare(client: VIAM.RobotClient) {
// Replace with the name of the base on your machine.
const name = "viam_base";
const baseClient = new VIAM.BaseClient(client, name);
try {
button().disabled = true;
for (let i = 0; i < 4; i++) {
console.log("move straight");
await baseClient.moveStraight(500, 500);
console.log("spin 90 degrees");
await baseClient.spin(90, 100);
}
} finally {
button().disabled = false;
}
}
// This function gets the button element
function button() {
return <HTMLButtonElement>document.getElementById("main-button");
}
const main = async () => {
const host = "ADDRESS_FROM_VIAM_APP";
const machine = await VIAM.createRobotClient({
host,
credential: {
type: "api-key",
// Replace "<API-KEY>" (including brackets) with your machine's API key
payload: "<API-KEY>",
},
// Replace "<API-KEY-ID>" (including brackets) with your machine's API key ID
authEntity: "<API-KEY-ID>",
signalingAddress: "https://app.viam.com:443",
});
button().onclick = async () => {
await moveInSquare(machine);
};
button().disabled = false;
};
main().catch((error) => {
console.error("encountered an error:", error);
});
/// This is the BaseScreen, which allows us to control a Base.
import 'package:flutter/material.dart';
import 'package:viam_sdk/viam_sdk.dart';
import 'package:viam_sdk/widgets.dart';
class BaseScreen extends StatelessWidget {
final Base base;
const BaseScreen(this.base, {super.key});
Future<void> moveSquare() async {
for (var i=0; i<4; i++) {
await base.moveStraight(500, 500);
await base.spin(90, 100);
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text(base.name)),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
ElevatedButton(
onPressed: moveSquare,
child: const Text('Move Base in Square'),
),
]))
,);}}
/// This is the screen that shows the resources available on a robot (or smart machine).
/// It takes in a Viam app client instance, as well as a robot client.
/// It then uses the Viam client instance to create a connection to that robot client.
/// Once the connection is established, you can view the resources available
/// and send commands to them.
import 'package:flutter/material.dart';
import 'base_screen.dart';
import 'package:viam_sdk/protos/app/app.dart';
import 'package:viam_sdk/viam_sdk.dart';
class RobotScreen extends StatefulWidget {
final Viam _viam;
final Robot robot;
const RobotScreen(this._viam, this.robot, {super.key});
@override
State<RobotScreen> createState() => _RobotScreenState();
}
class _RobotScreenState extends State<RobotScreen> {
/// Similar to previous screens, start with [_isLoading] to true.
bool _isLoading = true;
/// This is the [RobotClient], which allows you to access
/// all the resources of a Viam Smart Machine.
/// This differs from the [Robot] provided to us in the widget constructor
/// in that the [RobotClient] contains a direct connection to the Smart Machine
/// and its resources. The [Robot] object simply contains information about
/// the Smart Machine, but is not actually connected to the machine itself.
///
/// This is initialized late because it requires an asynchronous
/// network call to establish the connection.
late RobotClient client;
@override
void initState() {
super.initState();
// Call our own _initState method to initialize our state.
_initState();
}
@override
void dispose() {
// You should always close the [RobotClient] to free up resources.
// Calling [RobotClient.close] will clean up any tasks and
// resources created by Viam.
client.close();
super.dispose();
}
/// This method will get called when the widget initializes its state.
/// It exists outside the overridden [initState] function since it's async.
Future<void> _initState() async {
// Using the authenticated [Viam] the received as a parameter,
// the app can obtain a connection to the Robot.
// There is a helpful convenience method on the [Viam] instance for this.
final robotClient = await widget._viam.getRobotClient(widget.robot);
setState(() {
client = robotClient;
_isLoading = false;
});
}
/// A computed variable that returns the available [ResourceName]s of
/// this robot in an alphabetically sorted list.
List<ResourceName> get _sortedResourceNames {
return client.resourceNames..sort((a, b) => a.name.compareTo(b.name));
}
bool _isNavigable(ResourceName rn) {
if (rn.subtype == Base.subtype.resourceSubtype) {
return true;
}
return false;
}
void _navigate(ResourceName rn) {
if (rn.subtype == Base.subtype.resourceSubtype) {
final base = Base.fromRobot(client, rn.name);
Navigator.of(context).push(MaterialPageRoute(builder: (_) => BaseScreen(base)));
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text(widget.robot.name)),
body: _isLoading
? const Center(child: CircularProgressIndicator.adaptive())
: ListView.builder(
itemCount: client.resourceNames.length,
itemBuilder: (_, index) {
final resourceName = _sortedResourceNames[index];
return ListTile(
title: Text(resourceName.name),
subtitle: Text(
'${resourceName.namespace}:${resourceName.type}:${resourceName.subtype}'),
onTap: () => _navigate(resourceName),
trailing: _isNavigable(resourceName) ? Icon(Icons.chevron_right) : SizedBox.shrink(),
);
}));
}
}
#include <boost/optional.hpp>
#include <string>
#include <vector>
#include <viam/sdk/robot/client.hpp>
#include <viam/sdk/components/motor.hpp>
#include <viam/sdk/components/base.hpp>
#include <viam/sdk/components/camera.hpp>
#include <viam/sdk/components/encoder.hpp>
using namespace viam::sdk;
using namespace viam::sdk;
using std::cerr;
using std::cout;
using std::endl;
void move_in_square(std::shared_ptr<viam::sdk::Base> base) {
for (int i = 0; i < 4; ++i) {
cout << "Move straight" << endl;
// Move the base forward 600mm at 500mm/s
base->move_straight(500, 500);
cout << "Spin" << endl;
// Spin the base by 90 degree at 100 degrees per second
base->spin(90, 100);
}
}
int main() {
std::string host("ADDRESS FROM THE VIAM APP");
DialOptions dial_opts;
// Replace "<API-KEY-ID>" with your machine's api key ID
dial_opts.set_entity(std::string("<API-KEY-ID>"));
// Replace "<API-KEY>" with your machine's api key
Credentials credentials("api-key", "<API-KEY>");
dial_opts.set_credentials(credentials);
boost::optional<DialOptions> opts(dial_opts);
Options options(0, opts);
auto machine = RobotClient::at_address(host, options);
std::cout << "Resources:\n";
for (const Name& resource : machine->resource_names()) {
std::cout << "\t" << resource << "\n";
}
std::string base_name("viam_base");
cout << "Getting base: " << base_name << endl;
std::shared_ptr<Base> base;
try {
base = machine->resource_by_name<Base>(base_name);
move_in_square(base);
} catch (const std::exception& e) {
cerr << "Failed to find " << base_name << ". Exiting." << endl;
throw;
}
return EXIT_SUCCESS;
}
Next steps
Now that you have run your first code to control a machine running Viam code to control your machine, move to the next quickstart to learn how to configure and control a motor:
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