Add a sensor

Add a sensor to your machine’s configuration so you can read environmental data from the Viam app and from code.

Concepts

The sensor component provides a single method: GetReadings, which returns a map of key-value pairs. This simple interface works for any sensor that produces named measurements.

Most physical sensors in Viam come from modules in the Viam registry rather than built-in models. This is because the sensor ecosystem is enormous. Thousands of different devices with different communication protocols exist, and modules cover specific hardware while keeping the same GetReadings API.

Steps

1. Add a sensor component

1. Click the + button.
2. Select Configuration block.
3. Search for the model that matches your sensor hardware. Search by sensor name or chip (for example, DHT22, BME280, SHT31). For I2C or serial sensors, you can also search by protocol or manufacturer.
4. Name your sensor (for example, temperature-sensor) and click Create.

If no model exists for your sensor, you can write a driver module to add support.

2. Configure sensor attributes

Attributes vary by sensor module. Common patterns:

I2C sensor (for example, BME280, SHT31):

{
  "board": "my-board",
  "i2c_bus": "1",
  "i2c_address": 119
}

Serial sensor (for example, air quality monitors):

{
  "serial_path": "/dev/ttyUSB0",
  "baud_rate": 9600
}

GPIO sensor (for example, ultrasonic distance):

{
  "board": "my-board",
  "trigger_pin": "11",
  "echo_pin": "13"
}

Check the module’s documentation in the registry for the exact attributes your sensor needs.

3. Save and test

Click Save, then expand the TEST section.

• The test panel shows the output of GetReadings, a table of named values.
• Verify the readings make sense (for example, room temperature should be roughly 20-25°C).

Try it

Read sensor data programmatically and print it.

To get the credentials for the code below, go to your machine’s page in the Viam app, click the CONNECT tab, and select SDK code sample. Toggle Include API key on. Copy the machine address, API key, and API key ID from the code sample. When you run the code below, you’ll see sensor readings printed once per second. Verify the values make sense for your environment.

pip install viam-sdk

import asyncio
from viam.robot.client import RobotClient
from viam.components.sensor import Sensor


async def main():
    opts = RobotClient.Options.with_api_key(
        api_key="YOUR-API-KEY",
        api_key_id="YOUR-API-KEY-ID"
    )
    robot = await RobotClient.at_address("YOUR-MACHINE-ADDRESS", opts)

    sensor = Sensor.from_robot(robot, "temperature-sensor")

    # Get readings 5 times, once per second
    for i in range(5):
        readings = await sensor.get_readings()
        print(f"Reading {i + 1}: {readings}")
        await asyncio.sleep(1)

    await robot.close()

if __name__ == "__main__":
    asyncio.run(main())

python sensor_test.py

Reading 1: {'temperature_celsius': 22.5, 'humidity_percent': 45.2}
Reading 2: {'temperature_celsius': 22.5, 'humidity_percent': 45.3}
...

mkdir sensor-test && cd sensor-test
go mod init sensor-test
go get go.viam.com/rdk

package main

import (
    "context"
    "fmt"
    "time"

    "go.viam.com/rdk/components/sensor"
    "go.viam.com/rdk/logging"
    "go.viam.com/rdk/robot/client"
    "go.viam.com/rdk/utils"
)

func main() {
    ctx := context.Background()
    logger := logging.NewLogger("sensor-test")

    robot, err := client.New(ctx, "YOUR-MACHINE-ADDRESS", logger,
        client.WithCredentials(utils.Credentials{
            Type:    utils.CredentialsTypeAPIKey,
            Payload: "YOUR-API-KEY",
        }),
        client.WithAPIKeyID("YOUR-API-KEY-ID"),
    )
    if err != nil {
        logger.Fatal(err)
    }
    defer robot.Close(ctx)

    s, err := sensor.FromProvider(robot, "temperature-sensor")
    if err != nil {
        logger.Fatal(err)
    }

    // Get readings 5 times, once per second
    for i := 0; i < 5; i++ {
        readings, err := s.Readings(ctx, nil)
        if err != nil {
            logger.Fatal(err)
        }
        fmt.Printf("Reading %d: %v\n", i+1, readings)
        time.Sleep(1 * time.Second)
    }
}

go run main.go

Troubleshooting

What’s next

• Sensor API reference: full method documentation.
• Capture and Sync Data: automatically capture sensor readings and sync them to the cloud.
• What is a module?: write a module that takes action based on sensor readings.