Focus This Week

This week is focused on Interface and Application Programming. The objectives were to compare development toolchains for creating graphical user interfaces (GUIs), and write a computer application that communicates with an embedded input/output device. I developed a Python-based Go-Kart Telemetry Dashboard application using the Tkinter library that reads serial data from the ESP32-C3 board and updates live virtual dials for speed, throttle, and battery voltage.

Group Assignment — GUI Toolchain Comparisons

The group assignment was to review and compare different software platforms and frameworks for interface programming. We built simple serial text loggers using Python, JavaScript, and Processing. The complete group analysis is available on the Fablab Dilijan Group Assignment Page.

GUI Frameworks Comparison

Individual Assignment — Python Serial Telemetry App

I wrote a desktop application in Python 3 using **PySerial** for data collection and **Tkinter** for the user interface. The app parses a comma-separated data stream from the microcontroller, extracting variables to render a live graphical dashboard.

Data Protocol Structure

The microcontroller sends text packets over the USB virtual COM port in CSV format:
$THROTTLE,SPEED,VOLTAGE\r\n
Example frame: $78,35,41.8 (representing 78% throttle, 35 km/h, and 41.8V battery level).

Python Application Source Code

This script opens the COM port, runs an asynchronous background thread to read the incoming serial data, and uses Tkinter callbacks to update the graphic dials and text boxes:

# Python 3 Telemetry GUI - Tkinter & PySerial
import tkinter as tk
from tkinter import ttk
import serial
import threading
import sys

# Configure Serial connection
SERIAL_PORT = 'COM3' # Change to '/dev/ttyUSB0' on Linux
BAUD_RATE = 115200

try:
    ser = serial.Serial(SERIAL_PORT, BAUD_RATE, timeout=0.1)
except Exception as e:
    print(f"Error opening port {SERIAL_PORT}: {e}")
    ser = None

class TelemetryApp(tk.Tk):
    def __init__(self):
        super().__init__()
        self.title("Go-Kart Live Telemetry")
        self.geometry("400x300")
        self.configure(bg="#222")
        
        # Heading
        self.header = tk.Label(self, text="KART TELEMETRY STATUS", font=("Arial", 16, "bold"), fg="cyan", bg="#222")
        self.header.pack(pady=10)
        
        # Speed Label
        self.speed_val = tk.StringVar(value="0 km/h")
        self.speed_lbl = tk.Label(self, textvariable=self.speed_val, font=("Arial", 28, "bold"), fg="white", bg="#222")
        self.speed_lbl.pack(pady=10)
        
        # Throttle Progress Bar
        self.bar_lbl = tk.Label(self, text="Throttle Level:", font=("Arial", 10), fg="white", bg="#222")
        self.bar_lbl.pack()
        self.progress = ttk.Progressbar(self, orient="horizontal", length=300, mode="determinate")
        self.progress.pack(pady=10)
        
        # Voltage Label
        self.volt_val = tk.StringVar(value="Voltage: 0.0V")
        self.volt_lbl = tk.Label(self, textvariable=self.volt_val, font=("Arial", 12), fg="yellow", bg="#222")
        self.volt_lbl.pack(pady=10)
        
        # Run background thread for serial read
        self.running = True
        self.thread = threading.Thread(target=self.read_serial, daemon=True)
        self.thread.start()
        
    def read_serial(self):
        while self.running:
            if ser and ser.in_waiting > 0:
                try:
                    line = ser.readline().decode('utf-8').strip()
                    if line.startswith("$"):
                        # Parse CSV data: e.g. "$78,35,41.8"
                        data = line[1:].split(",")
                        if len(data) == 3:
                            throttle = int(data[0])
                            speed = int(data[1])
                            voltage = float(data[2])
                            
                            # Update Tkinter variables safely
                            self.progress['value'] = throttle
                            self.speed_val.set(f"{speed} km/h")
                            self.volt_val.set(f"Battery: {voltage} V")
                except Exception as e:
                    pass
                    
    def destroy(self):
        self.running = False
        if ser:
            ser.close()
        super().destroy()

if __name__ == "__main__":
    app = TelemetryApp()
    app.mainloop()

Original Code Files

Download the Python telemetry GUI source code script:

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Week 15 — Summary

This week focused on software interfaces, data formatting, and desktop integrations. Here is a summary of the accomplishments: