sfz-pitechcar 1.0.0

Control software for remote Fischertechnik Maker Car with SFZ PCB.

SFZ-PiTechCar (Python Package)

Python-based software for controlling a Fischertechnik Maker Kit car via a custom-built PCB and Raspberry Pi. Provides precise motor control (forward/backward) and steering via a servo. Supports the official 8.4V Fischertechnik NiMH battery. Additional sensors can be connected using stemmaQT connectors and controlled with CircuitPython-based libraries.

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Required Hardware

	Fischertechnik Maker Kit Car The base platform for the PiTech Car project, including chassis, wheels, motors, and steering mechanism.
	Fischertechnik 8.4V NiMH Battery Provides reliable power for the PiTech Car HAT+, motors, servo, and Raspberry Pi. Includes a standard charger. Note: Higher-power Raspberry Pi models may draw too much current, causing undervoltage warnings or preventing the Raspberry Pi from starting. It is recommended to use a Raspberry Pi 3 or Raspberry Pi 3A+.
	Raspberry Pi 3A+ Serves as the main controller for the car, running the Python software and handling communication with the PiTech Car HAT+. Other Raspberry Pi models (e.g., 3B+, 4) are also compatible.
	Custom-Built PiTech Car HAT+, Falko Schmidt, SFZ, 2025 Handles motor control (forward/backward) and steering via servo, interfaces with the battery, and provides stemmaQT connectors for additional sensors. Designed specifically to integrate seamlessly with the Python control software and Raspberry Pi.
	Pi Hut Controller (Remote Control) Used to control the PiTech Car. Interfaces with the Raspberry Pi over USB, allowing the user to drive, steer, and send commands remotely. Only the joysticks are used; the buttons can be assigned for custom functionality.

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Software Prerequisites

⚠️ This software only works on Raspberry Pi systems!

Create a virtual Python environment to isolate and manage all required software libraries:

python -m venv ftberry_python_venv
source ftberry_python_venv/bin/activate

The Python control software requires several CircuitPython libraries to interface with sensors. On Raspberry Pi, these libraries rely on the Blinka compatibility layer from Adafruit. To install Blinka, run the following commands:

cd ~
pip3 install --upgrade adafruit-python-shell
wget https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/raspi-blinka.py
sudo -E env PATH=$PATH python3 raspi-blinka.py

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Software Installation

Before installing the software, make sure the Python virtual environment is activated. Then install the software by running:

pip install sfz-pitechcar

All required dependencies listed below will be installed automatically.

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Pre-Usage

Before running the software, you need to identify and profile the controller you are using. The Python library ApproxEng Input is used for this purpose. Follow the official profiling instructions here:

ApproxEng Input Profiling Guide

After profiling, move the generated YAML file into the correct directory as described in the documentation. Once this is done, your controller is ready for use with the PiTech Car software.

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Usage

After installing the package, the pitechcar command will be available in your shell.

Basic usage

Start the car with the default (mixed) joystick control mode:

pitechcar

Control modes

You can select how the joystick axes are mapped using the --control option:

• mixed (default):
  • Left joystick vertical axis controls speed
  • Right joystick horizontal axis controls steering
• left_only:
  • Left joystick controls both speed and steering
• right_only:
  • Right joystick controls both speed and steering

Example:

pitechcar --control left_only

Stopping the car

Press Ctrl+C at any time to safely stop the motor and shut down all hardware components.

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Auto-start on boot

To have PiTechCar start automatically when the system boots, you can set it up as a systemd service. First, create a small shell script that activates your virtual environment and starts PiTechCar:

cd ~
nano pitechcar_controller.sh

Add the following content (adjust the virtual environment path and control mode if needed):

#!/bin/bash
source ~/ftberry_python_venv/bin/activate
pitechcar

Make the script executable:

chmod +x ~/pitechcar_controller.sh

Next, create a new service file:

sudo nano /etc/systemd/system/pitechcar_controller.service

Paste the following configuration and replace USERNAME with your actual Linux username:

[Unit]
Description=PiTechCar Controller
After=usb-devices.target
Wants=usb-devices.target

[Service]
Type=simple
User=USERNAME
WorkingDirectory=/home/USERNAME
ExecStart=/bin/bash /home/USERNAME/pitechcar_controller.sh
Restart=on-failure
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

Enable the service so it starts automatically on boot:

sudo systemctl enable pitechcar_controller.service

Once enabled, PiTechCar will launch automatically on every boot. If you want to start it immediately, you can either reboot or enter this command (without reboot):

sudo systemctl start pitechcar_controller.service

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Python Package Dependencies

ℹ️ All dependencies listed here are automatically installed with the package.

• ApproxEng Input 2.6.4 (Linux only)
  Provides joystick and controller input handling.

• Adafruit Python Shell 1.11.1
  Helps run Python scripts on the Raspberry Pi via the shell, required for Blinka.

• Adafruit CircuitPython PCA9685 3.4.20
  Controls PCA9685 PWM controllers.

• Adafruit CircuitPython ServoKit 1.3.22
  Provides an easy interface to control multiple servos via ServoKit.

• Adafruit CircuitPython MCP3xxx 1.5.0
  Reads analog sensors via MCP3008/MCP3208 ADC chips.

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Project Structure

sfz-pitechcar/
├── assets/              # Images and diagrams for README
├── scripts/             # Example scripts
│   └── run_car.py       # Main script to start the PiTech Car
├── src/pitechcar/       # Python package
│   ├── hardware/        # Low-level hardware modules (motors, sensors, battery)
│   └── modules/         # Higher-level control modules (motor, battery, WiFi)
├── README.md
├── pyproject.toml

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Contributing

Contributions are welcome! To contribute, please fork the repository, make your changes, and submit a merge request. For major changes or feature additions, consider opening an issue first to discuss your ideas.

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License

This project is licensed under the BSD-3-Clause License. © 2026 Falko Schmidt.