This system was developed for use on Vassar College's HARPER project, a robotics platform for research and education. The SPARCC Platform is designed to abstract the communication between a Python program and an Arduino, allowing for easy control of PWM servos and stepper drivers, along with easy querying of sensors. The system is designed to be easily extensible, allowing for the addition of new components with minimal changes to the existing code. An example of it in use can be seen here.
Note that the example project may not be up-to-date with the current version of the platform. The example project is a good reference for how to use the platform, but the code may not be directly compatible.
- Overview
- Should I Use This For My Project?
- Installation
- Example Usage
- Software Overview
- Hardware Overview
- Troubleshooting
A Python class (ArduinoInterface) sends serial commands and queries to a connected Arduino/microcontroller (designed for a Mega2560, but any microcontroller works), collecting response data. When adding a new servo, stepper, or sensor, configuration is required on BOTH ends (local Python and compiled C++ Arduino Code). "Sensors" can refer to any input device or to software sensors (e.g., querying the arduino for the current time).
This platform helps projects that require computation beyond the abilities of an Arduino (e.g., machine learning, computer vision, etc.) but still need to interface with stepper motors, servos, and digital/analog sensors. Though a Raspberry Pi sometimes fills this need, they have less compute power than a desktop, fewer GPIO pins than many Arduinos, and lack the extensive collection of Arduino libraries.
If your project requires communication between an Arduino (for hardware control) and a Python program (for computation), this platform is a good choice. If you want to see it in action, check out the example project.
Note that the example project may not be up-to-date with the current version of the platform. The example project is a good reference for how to use the platform, but the code may not be directly compatible.
To install, download this repository and install the required Python packages with pip install -r requirements.txt. The Arduino code is compiled with PlatformIO, which can be installed as a VSCode extension. If you need an overview of using the platform, see the example walkthrough.
This brief overview shows how the Arduino supports:
- mass 4.8-6V servo control with an Adafruit Shield
- custom-voltage ("loose") servos
- stepper motors
- analog and digital sensors
There are three classes that the ArduinoInterface uses:
Represents shield and loose servos.
Represents a stepper motor, accounting for inversion.
Represents any sensor attached to the Arduino. For more complex sensors, it is recommended to either integrate their information higher up in the P&A loop or extend the Sensor class and define more robust functions.
The ArduinoInterface class must be initialized with all servos, steppers, and sensors, along with being provided the port the Arduino is connected to (more on that later).
On the Arduino side, all sensors, servos, and steppers must be represented in their respective header file (see Servos.h as an example). To send code to the Arduino, this project is configured to use PlatformIO, a VSCode Extension.
Commands (and groups thereof) are abstracted; you never need to know what they look like to use this architecture. However, for troubleshooting, it can be helpful. Below, an example command is shown. More information is provided in the main.cpp file, which is commented with multiple examples.
s2=1000;t1=200;i0?; sets shield servo 2 to 1000, moves stepper 1 to 200, and queries sensor 0 (responding with the value).
For more information on setting up these components, see the example walkthrough
The Arduino should be connected over a USB-3+ connection. If you're not sure what this means, it's ok to ignore. USB-3 (usually indicated by a color like blue inside the port) is faster. It's ok to use a USB dock / dongle adapting from USB-C, which is generally very fast.
The currently-configured PlatformIO setup is for an Arduino Mega 2560. This can be changed, but it is recommended to use this Arduino because it has many GPIO pins and a relatively fast processor.
For more information on setting up these components, see the example walkthrough
See the troubleshooting guide for common issues and solutions.