Data from arduino to Grafana with USB COM

🔍 What We Want to Achieve

• Arduino sends temperature data via USB (Serial)
  
  

• A Python script reads this data and exposes it as a Prometheus metric at http://localhost:8000/metrics
  
  

• Prometheus scrapes the data every 5 seconds
  
  

• Grafana visualizes the temperature data
  
  

📁 Step 1: Project Folder

Create a folder on your Desktop called:

Arduino_To_Grafana

This folder will contain:

• Your Python script
  
  

• The Prometheus config file
  
  

• Eventually, Prometheus binaries
  
  

🎡 Step 2: Arduino Code (Simulation)

Open Arduino IDE, connect your Arduino Uno via USB, and upload the following sketch:

void setup() {

  Serial.begin(9600);

  randomSeed(analogRead(0));

}

void loop() {

  float value = random(200, 350) / 10.0; // Generate values from 20.0 to 35.0

  Serial.println(value);

  delay(1000); // 1 second

}

This test sketch simulates temperature data if you don't yet have a sensor.

Open Serial Monitor and ensure you're seeing values like:

28.00

27.10

33.50

🐍 Step 3: Python Script to Expose Metrics

✅ Install dependencies

Open PowerShell and run:

pip install prometheus_client pyserial

📝 Create the Python Script

Open Visual Studio Code, create a new file and paste the following:

import serial

from prometheus_client import start_http_server, Gauge

import time

# Configure your serial port and baud rate

SERIAL_PORT = 'COM5'  # Adjust this to match your port

BAUD_RATE = 9600

# Prometheus metric

temperature_gauge = Gauge('arduino_temperature_celsius', 'Temperature read from Arduino')

def read_serial():

    with serial.Serial(SERIAL_PORT, BAUD_RATE, timeout=1) as ser:

        while True:

            try:

                line = ser.readline().decode('utf-8').strip()

                if line:

                    print(f"Received: {line}")

                    temperature = float(line)

                    temperature_gauge.set(temperature)

            except Exception as e:

                print(f"Error: {e}")

            time.sleep(1)

if __name__ == "__main__":

    start_http_server(8000)  # Prometheus will scrape from here

    print("Prometheus metrics available at http://localhost:8000/metrics")

    read_serial()

Save it in Arduino_To_Grafana folder as:

serial_to_prometheus.py

▶ Run the Python Script

Open PowerShell and run:

cd "C:\Users\<yourname>\Desktop\Arduino_To_Grafana"

python serial_to_prometheus.py

You should see output like:

Prometheus metrics available at http://localhost:8000/metrics

Received: 26.80

Received: 30.50

📂 Step 4: Prometheus Configuration

📝 Create Config File

Create a file in the same folder named:

prometheus.yml

Paste this config:

global:

  scrape_interval: 5s

scrape_configs:

  - job_name: 'arduino_serial_reader'

    static_configs:

      - targets: ['localhost:8000']

▶ Run Prometheus

Make sure you downloaded Prometheus for Windows and placed the prometheus.exe inside the same folder or use the full path.

In PowerShell:

cd "C:\Users\<yourname>\Desktop\Arduino_To_Grafana"

.\prometheus.exe --config.file="prometheus.yml"

Open your browser to:

http://localhost:9090/

Enter this query:

arduino_temperature_celsius

You should see the current temperature value!

📊 Step 5: Visualize in Grafana

1. Open Grafana:
   
   

http://localhost:3000/

2. Log in with default credentials (admin / admin) and change password.
   
   

3. Go to Connections > Data Sources > Add new
   
   

4. Select Prometheus
   
   

   • URL: http://localhost:9090
     
     

   • Click Save & Test
     
     

5. Go to Dashboards > + Create > Dashboard
   
   

6. Click Add new panel
   
   

7. Use this query:
   
   

arduino_temperature_celsius

8. Choose a visualization (e.g., Graph, Stat, Gauge)
   
   

9. Click Apply, then Save Dashboard