An open-source, high-performance indoor cycling training application built with the Qt framework (C++17). MaximumTrainer delivers structured interval workouts with real-time power, cadence, heart rate, and speed feedback, and controls smart trainers automatically via FTMS ERG mode. Browse and sync workouts from intervals.icu, or import your own .erg / .mrc files.
| Item | Details |
|---|---|
| Language | C++17 (≈ 95 % C++) |
| Framework | Qt 5.15.2 (Windows / Linux) · Qt 6.7.3 (macOS) |
| Build file | PowerVelo.pro (qmake) |
| Qt modules | core · gui · widgets · network · bluetooth · webenginewidgets · printsupport · concurrent |
| Trainer protocol | Bluetooth LE Fitness Machine Service (FTMS / 0x1826) for ERG resistance control |
| Sensor profiles | Heart Rate (0x180D) · Cycling Speed & Cadence (0x1816) · Cycling Power (0x1818) |
| Workout formats | .erg, .mrc (imported and converted to the native .workout XML format) |
| Workout source | Integrated TrainerDay.com browser for online workout plans |
| Device | How to wake it |
|---|---|
| Smart trainer | Start pedalling for a few seconds |
| Power meter | Start pedalling |
| Heart rate strap | Moisten the electrode contacts and put it on |
| Speed / cadence sensor | Spin the crank or wheel |
- Launch MaximumTrainer and log in.
- From the main window open Preferences → Device Connections (or press the gear icon).
- Click Scan / Add Devices. The BTLE scanner lists every nearby Bluetooth LE device.
- Select the correct profile for each sensor:
| Profile | UUID | Data provided | Smart-trainer ERG control |
|---|---|---|---|
| Heart Rate Monitor | 0x180D | Heart rate (bpm) | No |
| Cycling Speed & Cadence | 0x1816 | Speed (km/h) · Cadence (RPM) | No |
| Cycling Power | 0x1818 | Power (W) | No |
| Fitness Machine (FTMS) | 0x1826 | Speed · Cadence · Power | Yes — enables ERG mode |
Important: Select the Fitness Machine (FTMS / 0x1826) profile for your smart trainer if you want the app to set resistance automatically. Choosing a plain Power or Speed profile disables ERG control.
- Paired sensors appear with a green indicator. You can pair multiple sensors simultaneously (e.g. FTMS trainer + HR strap).
If you have no hardware — or want to test a new workout — choose Simulation in the connection dialog. The software hub emits realistic drifting values:
| Channel | Base value | Range |
|---|---|---|
| Heart rate | 140 bpm | 125–165 bpm |
| Cadence | 90 rpm | 80–100 rpm |
| Speed | 28 km/h | 23–33 km/h |
| Power | 200 W | 170–260 W |
The simulator responds to ERG load commands from the workout player, making it a full end-to-end test of the training logic without any Bluetooth hardware.
Option A — TrainerDay.com library (integrated)
- Click the Find Workouts tab in the left sidebar.
- Browse or search the TrainerDay.com catalogue directly inside the app.
- Double-click a workout to download it to your local library.
Option B — Import a custom file
- Go to File → Import Workout (or File → Import Course Folder for batch import).
- Select one or more
.ergor.mrcfiles. - MaximumTrainer converts them to its native format and adds them to your library.
Option C — Create your own
Use the built-in Workout Creator (toolbar → pencil icon) to build structured intervals with configurable power, cadence, or HR targets.
| Mode | How it works | Best for |
|---|---|---|
| ERG | App automatically adjusts trainer resistance so your actual power matches the target wattage. You control only cadence. | Structured interval workouts |
| Slope / Manual | App sends a constant incline grade to the trainer. Resistance changes naturally with speed, just like riding outdoors. | Free-riding, ramp tests, courses |
The workout dialog switches to Slope mode automatically when the current interval has no power target, or when you press Increase / Decrease Difficulty to override ERG.
Once a workout starts you will see:
- Interval countdown — time remaining in the current interval, and total workout time elapsed / remaining.
- Target vs. Actual Power graph — a QWT-based real-time plot showing the structured intervals as coloured zones and your live power overlaid on top.
- Metrics widgets — live Heart Rate · Cadence · Speed · Power · Left/Right Power Balance (if a dual-sided power meter is connected) · SpO₂ (if an oxygen sensor is connected).
- Controls — Start/Pause, Skip Interval, Adjust Difficulty (±5 % FTP increments), and Lap.
Completed workout data is saved as a FIT activity file and can be uploaded to Strava, TrainingPeaks, or SelfLoops from the post-workout screen.
Note: Screenshots showing the cross-platform UI will be added here. Contributions of high-quality screenshots on each platform are welcome — please open a pull request.
| Platform | Description |
|---|---|
| Windows | Main workout player with power graph and metrics |
| macOS | Dashboard showing the TrainerDay.com workout browser |
| Linux | App running on Ubuntu — proof of cross-platform build |
| Device Manager | BTLE scanner with multiple sensors connected |
Before running MaximumTrainer on Linux, ensure the following prerequisites are met:
BlueZ is the Linux Bluetooth stack. Install it and make sure the daemon starts automatically:
sudo apt-get install -y bluez
sudo systemctl enable --now bluetoothVerify the daemon is active:
sudo systemctl status bluetoothIf the BLE device scanner shows an empty list and no error, the most common cause is that your account is not in the bluetooth group:
sudo usermod -aG bluetooth $USERImportant: Group changes take effect only after you log out and back in (or reboot). You can apply the change to the current shell session immediately — without logging out — by running:
newgrp bluetooth
MaximumTrainer requires a Bluetooth 4.0 or newer adapter to communicate with BLE sensors and trainers. Check your adapter:
hciconfig -aLook for LMP Version: 6 (BT 4.0) or higher in the output. If hciconfig is not available, use:
bluetoothctl showThe following kernel modules must be loaded:
| Module | Purpose |
|---|---|
bluetooth |
Core BLE/Bluetooth stack |
hci_uart |
UART-attached adapters (most USB dongles) |
btusb |
USB Bluetooth adapters |
Check and load if needed:
lsmod | grep -E "bluetooth|hci_uart|btusb"
# If missing, load manually:
sudo modprobe bluetooth
sudo modprobe btusbOn most modern distributions (Ubuntu 20.04+, Fedora 36+) these modules load automatically when a Bluetooth adapter is detected.
All three platforms are built and tested automatically via GitHub Actions CI (see .github/workflows/build.yml). Use PowerVelo.pro with qmake and a standard C++ compiler.
| Dependency | Version | Platform | Notes |
|---|---|---|---|
| Qt | 5.15.2 | Windows · Linux | Core framework |
| Qt | 6.7.3 | macOS | Core framework |
| QWT | 6.2.0 | all | Plotting widgets (built from source) |
| VLC-Qt | 1.1.0 (Win) · 1.1.1 from source (Linux) | Windows · Linux | Internet radio / video player |
| SFML | 2.6.1 (Win) · system package (Linux/macOS) | all | Audio feedback |
- Windows 10 version 1703 (Creators Update) or later is required. Windows 7, 8, and 8.1 are not supported (missing WinRT BLE APIs).
- A Bluetooth 4.0+ adapter with a WDM-compatible driver.
- No special permissions or manifest entries are needed.
Required tools: Qt 5.15.2 (msvc2019_64), Visual Studio 2019+ (MSVC), 7-Zip
Environment variables — set before running qmake:
| Variable | Description | Example |
|---|---|---|
QTDIR |
Qt installation root for the target arch | C:\Qt\5.15.2\msvc2019_64 |
VLCQT_DIR |
VLC-Qt installation root (forward slashes) | C:/vlcqt |
QMAKEFEATURES |
Path to QWT features directory | C:\qwt\features |
qmake invocation:
$env:QMAKEFEATURES = "C:\qwt\features"
qmake PowerVelo.pro `
"VLCQT_INSTALL=C:/vlcqt" `
"SFML_INSTALL=C:/sfml/SFML-2.6.1"
VLCQT_INSTALLmust point to the VLC-Qt package root (containingbin/,include/,lib/). The pre-built 1.1.0 win64 MSVC package places import.libfiles directly inlib/.
SFML_INSTALLmust point to the SFML root (the directory containinginclude/andlib/).
The Windows Kit libraries (Gdi32,User32) are resolved automatically by the MSVC linker — noWINKIT_INSTALLis needed when building inside an MSVC developer command prompt.
Download links:
- Qt 5.15.2: https://www.qt.io/download
- VLC-Qt 1.1.0 (win64 MSVC): https://github.com/vlc-qt/vlc-qt/releases/tag/1.1.0
- SFML 2.6.1 (vc17 64-bit): https://github.com/SFML/SFML/releases/tag/2.6.1
- QWT 6.2.0: https://sourceforge.net/projects/qwt/files/qwt/6.2.0/
Install system packages and build VLC-Qt from source, then build the app:
sudo apt-get install -y \
qtbase5-dev qtwebengine5-dev qtconnectivity5-dev \
libqwt-qt5-dev libsfml-dev libvlc-dev libvlccore-dev \
cmake build-essential
# Build VLC-Qt 1.1.1 from source
cd /tmp && git clone --branch 1.1.1 --depth 1 https://github.com/vlc-qt/vlc-qt
cd vlc-qt && mkdir build && cd build
cmake .. -DQT_VERSION=5 -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local
make -j$(nproc) && sudo make install && sudo ldconfig
# Build MaximumTrainer
cd /path/to/MaximumTrainer_Redux
export PATH=/usr/lib/qt5/bin:$PATH
qmake PowerVelo.pro "INCLUDEPATH+=/usr/local/include" "LIBS+=-L/usr/local/lib"
make -j$(nproc)Uses Qt 6.7.3 with Clang. QWT is built from source (non-framework) against Qt 6. VLC-Qt is optional on macOS.
macOS Bluetooth permission: The app's
mac/Info.plistincludes theNSBluetoothAlwaysUsageDescriptionkey, which is required by macOS 10.15+ for any app that accesses BLE devices. The first time the app attempts to connect a sensor, macOS will prompt for Bluetooth permission. This permission can be reviewed or revoked in System Settings → Privacy & Security → Bluetooth.
# Install Qt 6.7.3 via install-qt-action or the Qt Installer, then:
brew install sfml
# Build QWT 6.2.0 from source (non-framework, required for Qt 6)
curl -L -o /tmp/qwt.tar.bz2 "https://sourceforge.net/projects/qwt/files/qwt/6.2.0/qwt-6.2.0.tar.bz2/download"
tar -xjf /tmp/qwt.tar.bz2 -C /tmp && cd /tmp/qwt-6.2.0
sed -i.bak 's/QwtFramework//' qwtconfig.pri
qmake qwt.pro && make -j$(sysctl -n hw.logicalcpu) && sudo make install
# Build MaximumTrainer
cd /path/to/MaximumTrainer_Redux
qmake PowerVelo.pro \
"SFML_INSTALL=$(brew --prefix sfml)" \
"QWT_INSTALL=/usr/local/qwt-6.2.0"
makeBTLE sensor-data parsing is validated by a headless Qt Test suite in tests/btle/ — no real hardware required. Tests run on Ubuntu, Windows, and macOS in CI.
cd tests/btle
qmake btle_tests.pro
make -j$(nproc)
../../build/tests/btle_tests -v2
Language files are used at runtime from the /language folder.
You need Qt Linguist to open and generate a new language file (.qm file).
MaximumTrainer writes diagnostic messages (network errors, BLE events, OAuth login steps) to a log file. File logging is enabled by default on first launch; you can adjust the level or disable it in Preferences → Preferences & Profile → Logging.
| Platform | Default log file path |
|---|---|
| Windows | %APPDATA%\MaximumTrainer\MaximumTrainer.log(e.g. C:\Users\YourName\AppData\Roaming\MaximumTrainer\MaximumTrainer.log) |
| macOS | ~/Library/Application Support/MaximumTrainer/MaximumTrainer.log |
| Linux | ~/.local/share/MaximumTrainer/MaximumTrainer.log (XDG data dir; override with $XDG_DATA_HOME) |
Set the log level to Debug before reproducing an issue, then attach the log file to your bug report. The Open log file button in the Logging settings page opens the file directly in your default text editor.
For full troubleshooting guidance (including the Intervals.icu login page) see the User Guide — Log Files & Troubleshooting section.
Project now going through new revisions, with plans to enhance as an open-source interval trainer for indoor cycling & indoor rowing. backlog and work items can be found here