# Sending data over Serial

When a Pico is connected to a computer using a USB cable it is possible to send data over the serial connection

```{admonition}  Requirements
 :class: Hint

1.  A Pico
2.  A Computer connected to the Pico by USB 
```

## Set-up

Connect the Pico and Computer together using a USB cable.

The following program is run on the Computer, *Not The Pico*

```python
"""Simple program to log data sent over the serial port"""

import sys

import datetime as dt
import json
import serial


def readserial(comport: str, baudrate: int):
    """Function to read value from a serial port
    Assumes it is a json formatted string

    Parameters
    ----------
    comport : str
        the com port to connect to
    baudrate : int
        the baud rate of the connection
    """
    ser = serial.Serial(
        comport, baudrate, timeout=0.1
    )  # 1/timeout is the frequency at which the port is read

    try:
        while True:

            data = ser.readline().decode().strip()

            if "{" in data:
                #This assumes the data is JSON formated
                data = json.loads(data)
                print(data)
                # This can be saved to file or database depending on need
            elif data:
                #This just prints it, but it could be an error from the pico and therefore treated accordingly
                print(data)
    except KeyboardInterrupt:
        print("Ending Logging")
        sys.exit()


port = # The COM port that is connect
baud = 115200 # The baud rate of the connection, normally 115200

readserial(port, baud)

```

The code on the Pico is then below. Note that this code can recieve commands on the serial port

```python
import os
import sys
import microcontroller
import time
import json
import board

import supervisor



def hola(input_buffer:str):
    print(f"Hello from {inatorname}")
    
def reading():
    try:
        temp = 50   #Fixed as an example
        humidity = 45 # fixed as an example
        #Create dictionary
        json_dict = {"inator":inatorname,"temperature":temp,"humidity":humidity}  # Send data with JSON syntax
        json_data = json.dumps(json_dict)
        #print(f"{json_data}")
        return json_data
    except RuntimeError as e:
        print(f"Sensor read error: {e}")
        return None
#Retrieve variables from settings.toml
inatorname = os.getenv("INATORNAME")
accTime = float(os.getenv('ACQUIRETIME'))  #how often to acquire and transmit data

last_publish = 0
input_buffer = ""

while True:
    
    now = time.monotonic()
    if supervisor.runtime.serial_bytes_available:
        char = sys.stdin.read(1)
        if char in ("\n", "\r"):
            if input_buffer:
                print(f"Received command: {input_buffer}")
                if input_buffer == "hola":
                    hola(input_buffer)

                if input_buffer == "read":
                    json_data = reading()
                    if json_data:
                        print(f"{json_data}")
                        
                input_buffer = ""
        else:
            input_buffer += char
            
            
    if now - last_publish >= accTime:
        json_data = reading()
        if json_data:
            print(f"{json_data}")

        last_publish = now

    time.sleep(0.01)

```

in the settings.toml file on the Pico put the following:

```toml
INATORNAME = "NAME"
ACQUIRETIME = 5
```