update logger README to include detailed usage instructions and examples

Signed-off-by: YoungSoo Shin <shinys000114@gmail.com>

example/logger/README.md

@@ -1,41 +1,140 @@
-# Power Consumption Logger Example
+# Odroid PowerMate Logger and Plotter
 
-Based on this script, you can monitor power consumption and implement graph plotting.
+This directory contains two Python scripts to log power data from an Odroid Smart Power device and visualize it.
 
-## How to Run the Script
+1.  `logger.py`: Connects to the device's web server, authenticates, and logs real-time power data from its WebSocket to a CSV file.
+2.  `csv_2_plot.py`: Reads the generated CSV file and creates a plot image of the power, voltage, and current data over time.
 
-### Install Python Virtual Environment
+## Prerequisites
 
-```shell
+### 1. Clone this example
-sudo apt install virtualenv
+```bash
-virtualenv venv
+git clone https://github.com/hardkernel/odroid-powermate.git
-source venv/bin/activate
+cd odroid-powermate/example/logger
 ```
 
-### Install require package
+### 2. Python and Virtual Environment
 
-```shell
+It is highly recommended to use a Python virtual environment to manage project dependencies and avoid conflicts with other projects.
-pip install grpcio-tools requests websockets protobuf pandas matplotlib
+
+Ensure you have Python 3 installed.
+
+1.  **Create a virtual environment:**
+    Open your terminal in this directory and run:
+    ```bash
+    python3 -m venv venv
+    ```
+    This will create a `venv` directory containing the Python interpreter and libraries.
+
+2.  **Activate the virtual environment:**
+    *   **On Windows:**
+        ```powershell
+        .\venv\Scripts\activate
+        ```
+    *   **On macOS and Linux:**
+        ```bash
+        source venv/bin/activate
+        ```
+    Your terminal prompt should now show `(venv)` at the beginning, indicating that the virtual environment is active.
+
+### 3. Install Required Libraries
+
+With the virtual environment activated, install the necessary Python packages:
+
+```bash
+pip33 install requests websockets protobuf pandas matplotlib python-dateutil
 ```
 
-### Build `status_pb2.py`
+### 4. Protobuf Generated File
 
-```shell
+The `logger.py` script uses Google Protocol Buffers (Protobuf) to decode real-time data from the WebSocket. This requires a Python file, `status_pb2.py`, which is generated from a Protobuf definition file (`status.proto`).
-python -m grpc_tools.protoc -I ../../proto --python_out=. status.proto
+
+**How to Generate `status_pb2.py`:**
+
+1.  **Install Protobuf Compiler Tools:**
+    You need the `grpcio-tools` package, which includes the `protoc` compiler and Python plugins. You can install it via pip:
+    ```bash
+    pip3 install grpcio-tools
+    ```
+
+2.  **Locate the `.proto` file:**
+    Ensure you have the `status.proto` file in the current directory. This file defines the structure of the data messages.
+
+3.  **Run the Compiler:**
+    Execute the following command in your terminal. This command tells `protoc` to look for `status.proto` in the directory (`-I../../proto`) and generate the Python output file (`--python_out=.`) in the same place.
+    ```bash
+    python3 -m grpc_tools.protoc -I../../proto --python_out=. status.proto
+    ```
+After running this command, the `status_pb2.py` file will be created, and `logger.py` will be able to use it.
+
+## Usage
+
+The process is a two-step workflow: first log the data, then plot it.
+
+### Step 1: Log Power Data with `logger.py`
+
+Run `logger.py` to connect to your Odroid Smart Power device and save the data to a CSV file.
+
+**Syntax:**
+```bash
+python3 logger.py <host> -u <username> -p <password> -o <output_file.csv>
 ```
 
-### Execute script
+**Arguments:**
+*   `host`: The IP address or hostname of the Odroid Smart Power device (e.g., `192.168.1.50`).
+*   `-u`, `--username`: The username for logging in.
+*   `-p`, `--password`: The password for logging in.
+*   `-o`, `--output`: The path to save the output CSV file. This is required if you want to generate a plot.
 
-#### Power consumption collection
+**Example:**
-```shell
+
-# python3 logger.py -u <username> -o <name.csv> -p <password> <address>
+This command will log in and save the power data to `power_log.csv`.
-python3 logger.py -u admin -p password -o test.csv 192.168.30.5 
+
+```bash
+python3 logger.py 192.168.1.50 -u admin -p mypassword -o power_log.csv
 ```
 
-#### Plot data
+The script will continue to log data until you stop it with `Ctrl+C`.
 
-```shell
+### Step 2: Generate a Plot with `csv_2_plot.py`
-python3 csv_2_plot.py test.csv plot.png [--type power voltage current]
+
+Once you have a CSV log file, you can use `csv_2_plot.py` to create a visual graph.
+You can also use the csv file recorded from PowerMate Web.
+
+**Syntax:**
+```bash
+python3 csv_2_plot.py <input.csv> <output.png> [options]
 ```
 
-![plot.png](plot.png)
+**Arguments:**
+*   `input_csv`: The path to the CSV file generated by `logger.py`.
+*   `output_image`: The path to save the output plot image (e.g., `plot.png`).
+
+**Optional Arguments:**
+*   `-t`, `--type`: Specify which plots to generate. Choices are `power`, `voltage`, `current`. Default is all three.
+*   `-s`, `--source`: Specify which power sources to include. Choices are `vin`, `main`, `usb`. Default is all three.
+
+**Example 1: Default Plot**
+
+This command reads `power_log.csv` and generates a plot containing power, voltage, and current for all sources, saving it as `power_graph.png`.
+
+```bash
+python3 csv_2_plot.py power_log.csv power_graph.png
+```
+
+**Example 2: Custom Plot**
+
+This command generates a plot showing only the **power** and **current** for the **MAIN** and **USB** sources.
+
+```bash
+# main, usb power consumption
+python csv_2_plot.py power_log.csv custom_plot.png --type power --source main usb
+```
+
+## Example Output
+
+Running the plot script will generate an image file similar to this:
+
+![plot.png](img/plot.png)
+
+The 5-unit scale is highlighted with a blue dotted line, and the 10-unit scale is highlighted with a red dotted line.

example/logger/csv_2_plot.py

@@ -3,9 +3,11 @@ import argparse
 import matplotlib.dates as mdates
 import matplotlib.pyplot as plt
 import pandas as pd
+from dateutil.tz import gettz
+from matplotlib.ticker import MultipleLocator
 
 
-def plot_power_data(csv_path, output_path, plot_types):
+def plot_power_data(csv_path, output_path, plot_types, sources):
     """
     Reads power data from a CSV file and generates a plot image.
 
@@ -14,12 +16,19 @@ def plot_power_data(csv_path, output_path, plot_types):
         output_path (str): The path to save the output plot image.
         plot_types (list): A list of strings indicating which plots to generate
                            (e.g., ['power', 'voltage', 'current']).
+        sources (list): A list of strings indicating which power sources to plot
+                        (e.g., ['vin', 'main', 'usb']).
     """
     try:
         # Read the CSV file into a pandas DataFrame
-        # The 'timestamp' column is parsed as dates
         df = pd.read_csv(csv_path, parse_dates=['timestamp'])
         print(f"Successfully loaded {len(df)} records from '{csv_path}'")
+
+        # --- Timezone Conversion ---
+        local_tz = gettz()
+        df['timestamp'] = df['timestamp'].dt.tz_convert(local_tz)
+        print(f"Timestamp converted to local timezone: {local_tz}")
+
     except FileNotFoundError:
         print(f"Error: The file '{csv_path}' was not found.")
         return
@@ -27,57 +36,134 @@ def plot_power_data(csv_path, output_path, plot_types):
         print(f"An error occurred while reading the CSV file: {e}")
         return
 
+    # --- Calculate Average Interval ---
+    avg_interval_ms = 0
+    if len(df) > 1:
+        avg_interval = df['timestamp'].diff().mean()
+        avg_interval_ms = avg_interval.total_seconds() * 1000
+
+    # --- Calculate Average Voltages ---
+    avg_voltages = {}
+    for source in sources:
+        voltage_col = f'{source}_voltage'
+        if voltage_col in df.columns:
+            avg_voltages[source] = df[voltage_col].mean()
+
     # --- Plotting Configuration ---
-    plot_configs = {
+    scale_config = {
-        'power': {'title': 'Power Consumption', 'ylabel': 'Power (W)',
+        'power': {'steps': [5, 20, 50, 160]},
-                  'cols': ['vin_power', 'main_power', 'usb_power']},
+        'voltage': {'steps': [5, 10, 15, 25]},
-        'voltage': {'title': 'Voltage', 'ylabel': 'Voltage (V)',
+        'current': {'steps': [1, 2.5, 5, 10]}
-                    'cols': ['vin_voltage', 'main_voltage', 'usb_voltage']},
-        'current': {'title': 'Current', 'ylabel': 'Current (A)', 'cols': ['vin_current', 'main_current', 'usb_current']}
     }
-    channel_labels = ['VIN', 'MAIN', 'USB']
+    plot_configs = {
-    channel_colors = ['red', 'green', 'blue']
+        'power': {'title': 'Power Consumption', 'ylabel': 'Power (W)', 'cols': [f'{s}_power' for s in sources]},
+        'voltage': {'title': 'Voltage', 'ylabel': 'Voltage (V)', 'cols': [f'{s}_voltage' for s in sources]},
+        'current': {'title': 'Current', 'ylabel': 'Current (A)', 'cols': [f'{s}_current' for s in sources]}
+    }
+
+    channel_labels = [s.upper() for s in sources]
+    color_map = {'vin': 'red', 'main': 'green', 'usb': 'blue'}
+    channel_colors = [color_map[s] for s in sources]
 
     num_plots = len(plot_types)
     if num_plots == 0:
         print("No plot types selected. Exiting.")
         return
 
-    # Create a figure and a set of subplots based on the number of selected plot types.
+    fig, axes = plt.subplots(num_plots, 1, figsize=(15, 9 * num_plots), sharex=True, squeeze=False)
-    # sharex=True makes all subplots share the same x-axis (time)
+    axes = axes.flatten()
-    # squeeze=False ensures that 'axes' is always a 2D array, even if num_plots is 1.
-    fig, axes = plt.subplots(num_plots, 1, figsize=(15, 6 * num_plots), sharex=True, squeeze=False)
-    axes = axes.flatten()  # Flatten the 2D array to 1D for easier iteration
 
     # --- Loop through selected plot types and generate plots ---
     for i, plot_type in enumerate(plot_types):
         ax = axes[i]
         config = plot_configs[plot_type]
-
+        max_data_value = 0
         for j, col_name in enumerate(config['cols']):
-            ax.plot(df['timestamp'], df[col_name], label=channel_labels[j], color=channel_colors[j])
+            if col_name in df.columns:
+                ax.plot(df['timestamp'], df[col_name], label=channel_labels[j], color=channel_colors[j], zorder=2)
+                max_col_value = df[col_name].max()
+                if max_col_value > max_data_value:
+                    max_data_value = max_col_value
+            else:
+                print(f"Warning: Column '{col_name}' not found in CSV. Skipping.")
+
+        # --- Dynamic Y-axis Scaling ---
+        ax.set_ylim(bottom=0)
+        if plot_type in scale_config:
+            steps = scale_config[plot_type]['steps']
+            new_max = next((step for step in steps if step >= max_data_value), steps[-1])
+            ax.set_ylim(top=new_max)
 
         ax.set_title(config['title'])
         ax.set_ylabel(config['ylabel'])
         ax.legend()
-        ax.grid(True, which='both', linestyle='--', linewidth=0.5)
+
+        # --- Grid and Tick Configuration ---
+        y_min, y_max = ax.get_ylim()
+
+        # Keep the dynamic major_interval logic for tick LABELS
+        if plot_type == 'current' and y_max <= 2.5:
+            major_interval = 0.5
+        elif y_max <= 10:
+            major_interval = 2
+        elif y_max <= 25:
+            major_interval = 5
+        else:
+            major_interval = y_max / 5.0
+
+        ax.yaxis.set_major_locator(MultipleLocator(major_interval))
+        ax.yaxis.set_minor_locator(MultipleLocator(1))
+
+        # Disable the default major grid, but keep the minor one
+        ax.yaxis.grid(False, which='major')
+        ax.yaxis.grid(True, which='minor', linestyle='--', linewidth=0.6, zorder=0)
+
+        # Draw custom lines for 5 and 10 multiples, which are now the only major grid lines
+        for y_val in range(int(y_min), int(y_max) + 1):
+            if y_val == 0: continue
+            if y_val % 10 == 0:
+                ax.axhline(y=y_val, color='maroon', linestyle='--', linewidth=1.2, zorder=1)
+            elif y_val % 5 == 0:
+                ax.axhline(y=y_val, color='midnightblue', linestyle='--', linewidth=1.2, zorder=1)
+
+        # Keep the x-axis grid
+        ax.xaxis.grid(True, which='major', linestyle='--', linewidth=0.8)
 
     # --- Formatting the x-axis (Time) ---
-    # Improve date formatting on the x-axis
+    local_tz = gettz()
-    # Apply formatting to the last subplot's x-axis
     last_ax = axes[-1]
-    last_ax.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M:%S'))
+
-    last_ax.xaxis.set_major_locator(plt.MaxNLocator(15))  # Limit the number of ticks
+    if not df.empty:
-    plt.xlabel('Time')
+        last_ax.set_xlim(df['timestamp'].iloc[0], df['timestamp'].iloc[-1])
+
+    last_ax.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M:%S', tz=local_tz))
+    last_ax.xaxis.set_major_locator(plt.MaxNLocator(15))
+    plt.xlabel(f'Time ({local_tz.tzname(df["timestamp"].iloc[-1])})')
     plt.xticks(rotation=45)
 
-    # Add a main title to the figure
+    # --- Add a main title and subtitle ---
     start_time = df['timestamp'].iloc[0].strftime('%Y-%m-%d %H:%M:%S')
     end_time = df['timestamp'].iloc[-1].strftime('%H:%M:%S')
-    fig.suptitle(f'ODROID Power Log ({start_time} to {end_time})', fontsize=16, y=0.95)
+    main_title = f'PowerMate Log ({start_time} to {end_time})'
 
-    # Adjust layout to prevent titles/labels from overlapping
+    subtitle_parts = []
-    plt.tight_layout(rect=[0, 0, 1, 0.94])
+    if avg_interval_ms > 0:
+        subtitle_parts.append(f'Avg. Interval: {avg_interval_ms:.2f} ms')
+
+    voltage_strings = [f'{source.upper()} Avg: {avg_v:.2f} V' for source, avg_v in avg_voltages.items()]
+    if voltage_strings:
+        subtitle_parts.extend(voltage_strings)
+
+    subtitle = ' | '.join(subtitle_parts)
+
+    full_title = main_title
+    if subtitle:
+        full_title += f'\n{subtitle}'
+
+    fig.suptitle(full_title, fontsize=14)
+
+    # Adjust layout to make space for the subtitle
+    plt.tight_layout(rect=[0, 0, 1, 0.98])
 
     # --- Save the plot to a file ---
     try:
@@ -99,9 +185,17 @@ def main():
         help="Types of plots to generate. Choose from 'power', 'voltage', 'current'. "
              "Default is to generate all three."
     )
+    parser.add_argument(
+        "-s", "--source",
+        nargs='+',
+        choices=['vin', 'main', 'usb'],
+        default=['vin', 'main', 'usb'],
+        help="Power sources to plot. Choose from 'vin', 'main', 'usb'. "
+             "Default is to plot all three."
+    )
     args = parser.parse_args()
 
-    plot_power_data(args.input_csv, args.output_image, args.type)
+    plot_power_data(args.input_csv, args.output_image, args.type, args.source)
 
 
 if __name__ == "__main__":

example/logger/logger.py

@@ -3,7 +3,7 @@ import asyncio
 import csv
 import requests
 import websockets
-from datetime import datetime
+from datetime import datetime, timezone
 
 # Import the status_pb2.py file generated by `protoc`.
 # This file must be in the same directory as logger.py.
@@ -70,7 +70,7 @@ class OdroidPowerLogger:
 
                     # Write header
                     header = [
-                        'timestamp', 'uptime_sec',
+                        'timestamp', 'uptime_ms',
                         'vin_voltage', 'vin_current', 'vin_power',
                         'main_voltage', 'main_current', 'main_power',
                         'usb_voltage', 'usb_current', 'usb_power'
@@ -97,10 +97,10 @@ class OdroidPowerLogger:
                     # Process only if the payload type is 'sensor_data'
                     if status_message.WhichOneof('payload') == 'sensor_data':
                         sensor_data = status_message.sensor_data
-                        ts_dt = datetime.fromtimestamp(sensor_data.timestamp)
+                        ts_dt = datetime.fromtimestamp(sensor_data.timestamp_ms / 1000, tz=timezone.utc)
-                        ts_str = ts_dt.strftime('%Y-%m-%d %H:%M:%S')
+                        ts_str_print = ts_dt.strftime('%Y-%m-%d %H:%M:%S UTC')
 
-                        print(f"--- {ts_str} (Uptime: {sensor_data.uptime_sec}s) ---")
+                        print(f"--- {ts_str_print} (Uptime: {sensor_data.uptime_ms / 1000}s) ---")
 
                         # Print data for each channel
                         for name, channel in [('VIN', sensor_data.vin), ('MAIN', sensor_data.main),
@@ -110,8 +110,9 @@ class OdroidPowerLogger:
 
                         # Write to CSV if enabled
                         if csv_writer:
+                            ts_iso_csv = ts_dt.isoformat(timespec='milliseconds').replace('+00:00', 'Z')
                             row = [
-                                ts_dt.isoformat(), sensor_data.uptime_sec,
+                                ts_iso_csv, sensor_data.uptime_ms,
                                 sensor_data.vin.voltage, sensor_data.vin.current, sensor_data.vin.power,
                                 sensor_data.main.voltage, sensor_data.main.current, sensor_data.main.power,
                                 sensor_data.usb.voltage, sensor_data.usb.current, sensor_data.usb.power

main/include/nconfig.h

@@ -44,6 +44,7 @@ enum nconfig_type
     USB_CURRENT_LIMIT, ///< The maximum current limit for the USB out.
     PAGE_USERNAME, ///< Webpage username
     PAGE_PASSWORD, ///< Webpage password
+    SENSOR_PERIOD_MS, ///< Sensor period
     NCONFIG_TYPE_MAX,   ///< Sentinel for the maximum number of configuration types.
 };
 

main/nconfig/nconfig.c

@@ -30,6 +30,7 @@ const static char* keys[NCONFIG_TYPE_MAX] = {
     [USB_CURRENT_LIMIT] = "usb_climit",
     [PAGE_USERNAME] = "username",
     [PAGE_PASSWORD] = "password",
+    [SENSOR_PERIOD_MS] = "sensor_period",
 };
 
 struct default_value
@@ -54,6 +55,7 @@ struct default_value const default_values[] = {
     {USB_CURRENT_LIMIT, "3.0"},
     {PAGE_USERNAME, "admin"},
     {PAGE_PASSWORD, "password"},
+    {SENSOR_PERIOD_MS, "1000"},
 };
 
 esp_err_t init_nconfig()

main/proto/status.pb.h

@@ -25,8 +25,8 @@ typedef struct _SensorData {
     SensorChannelData main;
     bool has_vin;
     SensorChannelData vin;
-    uint32_t timestamp;
+    uint64_t timestamp_ms;
-    uint32_t uptime_sec;
+    uint64_t uptime_ms;
 } SensorData;
 
 /* Contains WiFi connection status */
@@ -85,8 +85,8 @@ extern "C" {
 #define SensorData_usb_tag                       1
 #define SensorData_main_tag                      2
 #define SensorData_vin_tag                       3
-#define SensorData_timestamp_tag                 4
+#define SensorData_timestamp_ms_tag              4
-#define SensorData_uptime_sec_tag                5
+#define SensorData_uptime_ms_tag                 5
 #define WifiStatus_connected_tag                 1
 #define WifiStatus_ssid_tag                      2
 #define WifiStatus_rssi_tag                      3
@@ -111,8 +111,8 @@ X(a, STATIC,   SINGULAR, FLOAT,    power,             3)
 X(a, STATIC,   OPTIONAL, MESSAGE,  usb,               1) \
 X(a, STATIC,   OPTIONAL, MESSAGE,  main,              2) \
 X(a, STATIC,   OPTIONAL, MESSAGE,  vin,               3) \
-X(a, STATIC,   SINGULAR, UINT32,   timestamp,         4) \
+X(a, STATIC,   SINGULAR, UINT64,   timestamp_ms,      4) \
-X(a, STATIC,   SINGULAR, UINT32,   uptime_sec,        5)
+X(a, STATIC,   SINGULAR, UINT64,   uptime_ms,         5)
 #define SensorData_CALLBACK NULL
 #define SensorData_DEFAULT NULL
 #define SensorData_usb_MSGTYPE SensorChannelData
@@ -172,7 +172,7 @@ extern const pb_msgdesc_t StatusMessage_msg;
 #define LoadSwStatus_size                        4
 #define STATUS_PB_H_MAX_SIZE                     SensorData_size
 #define SensorChannelData_size                   15
-#define SensorData_size                          63
+#define SensorData_size                          73
 
 #ifdef __cplusplus
 } /* extern "C" */

main/service/monitor.c

@@ -4,6 +4,7 @@
 
 #include "monitor.h"
 #include <nconfig.h>
+#include <sys/time.h>
 #include <time.h>
 #include "climit.h"
 #include "esp_log.h"
@@ -89,9 +90,10 @@ static void send_pb_message(const pb_msgdesc_t* fields, const void* src_struct)
 
 static void sensor_timer_callback(void* arg)
 {
-    int64_t uptime_us = esp_timer_get_time();
+    struct timeval tv;
-    uint32_t uptime_sec = (uint32_t)(uptime_us / 1000000);
+    gettimeofday(&tv, NULL);
-    uint32_t timestamp = (uint32_t)time(NULL);
+    uint64_t timestamp_ms = (uint64_t)tv.tv_sec * 1000 + (uint64_t)tv.tv_usec / 1000;
+    uint64_t uptime_ms = (uint64_t)esp_timer_get_time() / 1000;
 
     StatusMessage message = StatusMessage_init_zero;
     message.which_payload = StatusMessage_sensor_data_tag;
@@ -120,8 +122,8 @@ static void sensor_timer_callback(void* arg)
 
     // datalog_add(timestamp, channel_data_log);
 
-    sensor_data->timestamp = timestamp;
+    sensor_data->timestamp_ms = timestamp_ms;
-    sensor_data->uptime_sec = uptime_sec;
+    sensor_data->uptime_ms = uptime_ms;
 
     send_pb_message(StatusMessage_fields, &message);
 }
@@ -289,6 +291,25 @@ void init_status_monitor()
     xTaskCreate(shutdown_load_sw_task, "shutdown_sw_task", configMINIMAL_STACK_SIZE * 3, NULL, 15,
                 &shutdown_task_handle);
 
-    ESP_ERROR_CHECK(esp_timer_start_periodic(sensor_timer, 1000000));
+    nconfig_read(SENSOR_PERIOD_MS, buf, sizeof(buf));
+    ESP_ERROR_CHECK(esp_timer_start_periodic(sensor_timer, strtol(buf, NULL, 10) * 1000));
     ESP_ERROR_CHECK(esp_timer_start_periodic(wifi_status_timer, 1000000 * 5));
 }
+
+esp_err_t update_sensor_period(int period)
+{
+    if (period < 500 || period > 10000) // 0.5 sec ~ 10 sec
+    {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    char buf[10];
+    sprintf(buf, "%d", period);
+    esp_err_t err = nconfig_write(SENSOR_PERIOD_MS, buf);
+    if (err != ESP_OK) {
+        return err;
+    }
+
+    esp_timer_stop(sensor_timer);
+    return esp_timer_start_periodic(sensor_timer, period * 1000);
+}

main/service/monitor.h

@@ -20,5 +20,6 @@ typedef struct
 } sensor_data_t;
 
 void init_status_monitor();
+esp_err_t update_sensor_period(int period);
 
 #endif // ODROID_REMOTE_HTTP_MONITOR_H

main/service/setting.c

@@ -6,6 +6,7 @@
 #include "esp_log.h"
 #include "esp_netif.h"
 #include "esp_timer.h"
+#include "monitor.h"
 #include "nconfig.h"
 #include "webserver.h"
 #include "wifi.h"
@@ -47,6 +48,11 @@ static esp_err_t setting_get_handler(httpd_req_t* req)
         cJSON_AddStringToObject(root, "baudrate", buf);
     }
 
+    if (nconfig_read(SENSOR_PERIOD_MS, buf, sizeof(buf)) == ESP_OK)
+    {
+        cJSON_AddStringToObject(root, "period", buf);
+    }
+
     // Add current limits to the response
     if (nconfig_read(VIN_CURRENT_LIMIT, buf, sizeof(buf)) == ESP_OK)
     {
@@ -174,6 +180,7 @@ static esp_err_t setting_post_handler(httpd_req_t* req)
     cJSON* net_type_item = cJSON_GetObjectItem(root, "net_type");
     cJSON* ssid_item = cJSON_GetObjectItem(root, "ssid");
     cJSON* baud_item = cJSON_GetObjectItem(root, "baudrate");
+    cJSON* period_item = cJSON_GetObjectItem(root, "period");
     cJSON* vin_climit_item = cJSON_GetObjectItem(root, "vin_current_limit");
     cJSON* main_climit_item = cJSON_GetObjectItem(root, "main_current_limit");
     cJSON* usb_climit_item = cJSON_GetObjectItem(root, "usb_current_limit");
@@ -289,6 +296,13 @@ static esp_err_t setting_post_handler(httpd_req_t* req)
         change_baud_rate(strtol(baudrate, NULL, 10));
         httpd_resp_sendstr(req, "{\"status\":\"baudrate_updated\"}");
     }
+    else if (period_item && cJSON_IsString(period_item))
+    {
+        const char* period_str = period_item->valuestring;
+        ESP_LOGI(TAG, "Received period set request: %s", period_str);
+        update_sensor_period(strtol(period_str, NULL, 10));
+        httpd_resp_sendstr(req, "{\"status\":\"period_updated\"}");
+    }
     else if (vin_climit_item || main_climit_item || usb_climit_item)
     {
         char num_buf[10];

page/index.html

@@ -141,8 +141,9 @@
             <div class="card border-top-0 rounded-0 rounded-bottom">
                 <div class="card-body">
                     <div class="d-flex justify-content-end mb-3">
-                        <a class="btn btn-primary" download="datalog.csv" href="/datalog.csv" style="display: none"><i
+                        <button id="record-button" class="btn btn-success me-2"><i class="bi bi-record-circle me-1"></i>Record</button>
-                                class="bi bi-download me-1"></i> Download CSV</a>
+                        <button id="stop-button" class="btn btn-danger me-2" style="display: none;"><i class="bi bi-stop-circle me-1"></i>Stop</button>
+                        <button id="download-csv-button" class="btn btn-primary" style="display: none;"><i class="bi bi-download me-1"></i>Download CSV</button>
                     </div>
                     <h5 class="card-title text-center mb-3">Power Metrics</h5>
                     <div class="row">
@@ -359,7 +360,7 @@
                         </form>
                     </div>
                     <div class="tab-pane fade" id="device-settings-pane" role="tabpanel">
-                        <div class="mb-3">
+                        <div class="mb-3 p-3 border rounded">
                             <label for="baud-rate-select" class="form-label">UART Baud Rate</label>
                             <select class="form-select" id="baud-rate-select">
                                 <option value="9600">9600</option>
@@ -372,6 +373,16 @@
                                 <option value="921600">921600</option>
                                 <option value="1500000" selected>1500000</option>
                             </select>
+                            <div class="d-flex justify-content-end mt-2">
+                                <button type="button" class="btn btn-primary btn-sm" id="baud-rate-apply-button">Apply</button>
+                            </div>
+                        </div>
+                        <div class="mb-3 p-3 border rounded">
+                            <label for="period-slider" class="form-label">Sensor Period: <span class="fw-bold text-primary" id="period-value">...</span> ms</label>
+                            <input type="range" class="form-range" id="period-slider" min="500" max="5000" step="100">
+                            <div class="d-flex justify-content-end mt-2">
+                                <button type="button" class="btn btn-primary btn-sm" id="period-apply-button">Apply</button>
+                            </div>
                         </div>
                         <hr>
                         <div class="mb-3">
@@ -380,7 +391,6 @@
                             <button type="button" class="btn btn-danger" id="reboot-button">Reboot Now</button>
                         </div>
                         <div class="d-flex justify-content-end pt-3 border-top mt-3">
-                            <button type="button" class="btn btn-primary me-2" id="baud-rate-apply-button">Apply</button>
                             <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Close</button>
                         </div>
                     </div>

page/src/api.js

@@ -104,7 +104,6 @@ export async function postNetworkSettings(payload) {
  * Posts the selected UART baud rate to the server.
  * @param {string} baudrate The selected baud rate.
  * @returns {Promise<Response>} A promise that resolves to the raw fetch response.
- * @throws {Error} Throws an error if the request fails.
  */
 export async function postBaudRateSetting(baudrate) {
     const response = await fetch('/api/setting', {
@@ -113,7 +112,24 @@ export async function postBaudRateSetting(baudrate) {
             'Content-Type': 'application/json',
             ...getAuthHeaders(),
         },
-        body: JSON.stringify({baudrate}),
+        body: JSON.stringify({ baudrate }),
+    });
+    return await handleResponse(response);
+}
+
+/**
+ * Posts the selected sensor period to the server.
+ * @param {string} period The selected period in milliseconds.
+ * @returns {Promise<Response>} A promise that resolves to the raw fetch response.
+ */
+export async function postPeriodSetting(period) {
+    const response = await fetch('/api/setting', {
+        method: 'POST',
+        headers: {
+            'Content-Type': 'application/json',
+            ...getAuthHeaders(),
+        },
+        body: JSON.stringify({ period }),
     });
     return await handleResponse(response);
 }

page/src/chart.js

@@ -216,7 +216,7 @@ function updateSingleChart(chart, metric, data, timeLabel) {
  * @param {Object} data - The new sensor data object from the WebSocket.
  */
 export function updateCharts(data) {
-    const timeLabel = new Date(data.timestamp * 1000).toLocaleTimeString();
+    const timeLabel = new Date(data.timestamp).toLocaleTimeString();
 
     updateSingleChart(charts.power, 'power', data, timeLabel);
     updateSingleChart(charts.voltage, 'voltage', data, timeLabel);

page/src/dom.js

@@ -76,6 +76,9 @@ export const apPasswordInput = document.getElementById('ap-password');
 // --- Device Settings Elements ---
 export const baudRateSelect = document.getElementById('baud-rate-select');
 export const baudRateApplyButton = document.getElementById('baud-rate-apply-button');
+export const periodSlider = document.getElementById('period-slider');
+export const periodValue = document.getElementById('period-value');
+export const periodApplyButton = document.getElementById('period-apply-button');
 export const rebootButton = document.getElementById('reboot-button');
 
 // --- Current Limit Settings Elements ---

page/src/events.js

@@ -77,8 +77,9 @@ export function setupEventListeners() {
     dom.networkApplyButton.addEventListener('click', ui.applyNetworkSettings);
     dom.apModeApplyButton.addEventListener('click', ui.applyApModeSettings);
     dom.baudRateApplyButton.addEventListener('click', ui.applyBaudRateSettings);
+    dom.periodApplyButton.addEventListener('click', ui.applyPeriodSettings);
 
-    // --- Device Settings (Reboot) ---
+    // --- Device Settings (Reboot & Period Slider) ---
     if (dom.rebootButton) {
         dom.rebootButton.addEventListener('click', () => {
             if (confirm('Are you sure you want to reboot the device?')) {
@@ -101,6 +102,12 @@ export function setupEventListeners() {
         });
     }
 
+    if (dom.periodSlider) {
+        dom.periodSlider.addEventListener('input', () => {
+            dom.periodValue.textContent = dom.periodSlider.value;
+        });
+    }
+
     // --- Current Limit Settings ---
     dom.vinSlider.addEventListener('input', () => updateSliderValue(dom.vinSlider, dom.vinValueSpan));
     dom.mainSlider.addEventListener('input', () => updateSliderValue(dom.mainSlider, dom.mainValueSpan));

page/src/main.js

@@ -30,6 +30,8 @@ import {setupEventListeners} from './events.js';
 
 // --- Globals ---
 // StatusMessage is imported directly from the generated proto.js file.
+let isRecording = false;
+let recordedData = [];
 
 // --- DOM Elements ---
 const loginContainer = document.getElementById('login-container');
@@ -50,6 +52,11 @@ const newUsernameInput = document.getElementById('new-username');
 const newPasswordInput = document.getElementById('new-password');
 const confirmPasswordInput = document.getElementById('confirm-password');
 
+// Metrics Tab DOM Elements
+const recordButton = document.getElementById('record-button');
+const stopButton = document.getElementById('stop-button');
+const downloadCsvButton = document.getElementById('download-csv-button');
+
 
 // --- WebSocket Event Handlers ---
 
@@ -88,13 +95,18 @@ function onWsMessage(event) {
                         USB: sensorData.usb,
                         MAIN: sensorData.main,
                         VIN: sensorData.vin,
-                        timestamp: sensorData.timestamp
+                        timestamp: sensorData.timestampMs,
+                        uptime: sensorData.uptimeMs
                     };
                     updateSensorUI(sensorPayload);
 
+                    if (isRecording) {
+                        recordedData.push(sensorPayload);
+                    }
+
                     // Update uptime separately from the sensor data payload
-                    if (sensorData.uptimeSec !== undefined) {
+                    if (sensorData.uptimeMs !== undefined) {
-                        updateUptimeUI(sensorData.uptimeSec);
+                        updateUptimeUI(sensorData.uptimeMs / 1000);
                     }
                 }
                 break;
@@ -233,6 +245,70 @@ function setupThemeToggles() {
     });
 }
 
+// --- Recording and Downloading Functions ---
+
+function startRecording() {
+    isRecording = true;
+    recordedData = [];
+    recordButton.style.display = 'none';
+    stopButton.style.display = 'inline-block';
+    downloadCsvButton.style.display = 'none';
+    console.log('Recording started.');
+}
+
+function stopRecording() {
+    isRecording = false;
+    recordButton.style.display = 'inline-block';
+    stopButton.style.display = 'none';
+    if (recordedData.length > 0) {
+        downloadCsvButton.style.display = 'inline-block';
+    }
+    console.log('Recording stopped. Data points captured:', recordedData.length);
+}
+
+function downloadCSV() {
+    if (recordedData.length === 0) {
+        alert('No data to download.');
+        return;
+    }
+
+    const headers = [
+        'timestamp', 'uptime_ms',
+        'vin_voltage', 'vin_current', 'vin_power',
+        'main_voltage', 'main_current', 'main_power',
+        'usb_voltage', 'usb_current', 'usb_power'
+    ];
+    const csvRows = [headers.join(',')];
+
+    recordedData.forEach(data => {
+        const timestamp = new Date(data.timestamp).toISOString();
+        const row = [
+            timestamp,
+            data.uptime,
+            Number(data.VIN.voltage).toFixed(3), Number(data.VIN.current).toFixed(3), Number(data.VIN.power).toFixed(3),
+            Number(data.MAIN.voltage).toFixed(3), Number(data.MAIN.current).toFixed(3), Number(data.MAIN.power).toFixed(3),
+            Number(data.USB.voltage).toFixed(3), Number(data.USB.current).toFixed(3), Number(data.USB.power).toFixed(3)
+        ];
+        csvRows.push(row.join(','));
+    });
+
+    const blob = new Blob([csvRows.join('\n')], { type: 'text/csv;charset=utf-8;' });
+    const link = document.createElement('a');
+    const url = URL.createObjectURL(blob);
+    
+    const now = new Date();
+    const pad = (num) => num.toString().padStart(2, '0');
+    const datePart = `${now.getFullYear().toString().slice(-2)}-${pad(now.getMonth() + 1)}-${pad(now.getDate())}`;
+    const timePart = `${pad(now.getHours())}-${pad(now.getMinutes())}`;
+    const filename = `powermate_${datePart}_${timePart}.csv`;
+
+    link.setAttribute('href', url);
+    link.setAttribute('download', filename);
+    link.style.visibility = 'hidden';
+    document.body.appendChild(link);
+    link.click();
+    document.body.removeChild(link);
+}
 
 // --- Application Initialization ---
 
@@ -263,6 +339,12 @@ function initializeMainAppContent() {
     initializeVersion();
     setupEventListeners(); // Attach main app event listeners
     logoutButton.addEventListener('click', handleLogout); // Attach logout listener
+    
+    // Attach listeners for recording/downloading
+    recordButton.addEventListener('click', startRecording);
+    stopButton.addEventListener('click', stopRecording);
+    downloadCsvButton.addEventListener('click', downloadCSV);
+
     connect();
 
     // Attach user settings form listener

page/src/ui.js

@@ -301,6 +301,24 @@ export async function applyBaudRateSettings() {
     }
 }
 
+/**
+ * Applies the selected sensor period by sending it to the server.
+ */
+export async function applyPeriodSettings() {
+    const period = dom.periodSlider.value;
+    dom.periodApplyButton.disabled = true;
+    dom.periodApplyButton.innerHTML = `<span class="spinner-border spinner-border-sm" aria-hidden="true"></span> Applying...`;
+
+    try {
+        await api.postPeriodSetting(period);
+    } catch (error) {
+        console.error('Error applying period:', error);
+    } finally {
+        dom.periodApplyButton.disabled = false;
+        dom.periodApplyButton.innerHTML = 'Apply';
+    }
+}
+
 /**
  * Fetches and displays the current network and device settings in the settings modal.
  */
@@ -338,6 +356,10 @@ export async function initializeSettings() {
         if (data.baudrate) {
             dom.baudRateSelect.value = data.baudrate;
         }
+        if (data.period) {
+            dom.periodSlider.value = data.period;
+            dom.periodValue.textContent = data.period;
+        }
 
     } catch (error) {
         console.error('Error initializing settings:', error);

page/src/utils.js

@@ -25,6 +25,7 @@ export function debounce(func, delay) {
  * @returns {string} The formatted uptime string.
  */
 export function formatUptime(totalSeconds) {
+    totalSeconds = Math.floor(totalSeconds);
     const days = Math.floor(totalSeconds / 86400);
     const hours = Math.floor((totalSeconds % 86400) / 3600);
     const minutes = Math.floor((totalSeconds % 3600) / 60);

proto/status.proto

@@ -12,8 +12,8 @@ message SensorData {
   SensorChannelData usb = 1;
   SensorChannelData main = 2;
   SensorChannelData vin = 3;
-  uint32 timestamp = 4;
+  uint64 timestamp_ms = 4;
-  uint32 uptime_sec = 5;
+  uint64 uptime_ms = 5;
 }
 
 // Contains WiFi connection status