Arduino Data Logger

Simple data Logs serial data from Arduino to a file without losing the ability to use Serial debugging.

Usage

usage: logger.py [-h] [--port PORT] [--baud BAUD] [--name NAME] [--timestamp]
                 [--timeout TIMEOUT] [--echo] [--no-handshake]
                 [--config CONFIG]

optional arguments:
  -h, --help            show this help message and exit
  --port PORT, -p PORT  Port to listen for communications on
  --baud BAUD, -b BAUD  Baud rate of the communications. By default 9600
  --name NAME, -n NAME  Name of output file
  --timestamp           Whether or not to apppend a timestamp to the output
                        file. By default, true
  --timeout TIMEOUT, -t TIMEOUT
                        Communications timeout in seconds. By default 0.1s
  --echo, -e            Echo logging data
  --no-handshake        Don't handshake with the Arduino to ensure its there.
  --config CONFIG, -c CONFIG
                        .json or .yaml config file with logger configuration

Command-line Side

Example Usage

./logger -p "COM3" --baud=115200

The above command will listen on COM3 and print output to a file called out [TIME].csv.

Using Config Files

It is also possible to use a configuration specified in a YAML or JSON files. This makes it less tedious to remember the configuration for the logger.

./logger --config="config.yml"

The above command will use the config specified in config.yml. Missing or null values in the config are treated as default values by the program. Extra values provided are ignored.

Arduino Side

Make sure to include the setup_log() function and to call after Serial.begin()

void setup_log()
{
    do
    {
        Serial.write(0xFF);
        delay(50);
    } while(Serial.read() != 0xFF);
    
    Serial.println(); // Flush the output for the logger
    Serial.println("VarX,VarY,VarZ");
}

void setup()
{
    Serial.begin(BAUDRATE);
    setup_log();
}

Installation

Requirements: Python 3.6+

git clone https://github.com/EmDash00/ArduinoLogger.git
pip install -r requirements.txt

Run with

./logger.py

Optional Dependency: arduino-cli

If arduino-cli is installed and is on PATH the program gains both the ability to automatically determine the port if only one device is connected. This makes the below command possible.

./logger.py

It also becomes possible to validate whether the specified PORT is a valid device. For example:

./logger.py
error: there are no valid devices

Theory of Operation

When the Arduino Data Logger starts, it initiates a "handshake" with device on the specified serial port (unless specified otherwise using --no-handshake). Functionally, this means it will wait for a byte containing 0xFF to be transmitted. On receiving the byte, the logger will return the "handshake" by sending back the same 0xFF byte.

Then, Arduino Data Logger simply reads lines printed to the serial port and logs it to a file. What you print is what you get. The exception to this rule is messages staring with ECHO:. These messages not logged to the file and instead only printed to the screen.

When the logger receives a line containing DONE, it stops listening and the program terminates.