developing_hardware_components.rst

Software interface to new hardware components

*** DRAFT VERSION - TO BE REVIEWED * This section is intended for developers of a new hardware component as part of an OhmPi system.

It presents some advices and best practices that should help developing new hardware components to work within an OhmPi system.

OhmPi is an open source system and contributions in terms of hardware and software are welcome. However, in order to maintain the project on tracks and promote exchange and reuse, it is necessary that contributors Developing a new hardware component is

Two cases should be distinguished when dealing with hardware development components: 1- Hardware component development that complies with the way the OhmPi Hardware System works. This means that this development focuses on improving a component (reduce cost, improve performance, adapt range to specific applications, design with easily available parts...). The created hardware component will expose the minimal functionalities required by hardware_system for this type of component.

2- Hardware component development that introduces changes in the way the OhmPi Hardware System works. This means that the development does not only focus on improving a single component but also on the way to operate the system. A discussion with developers of the OhmPi_Hardware and OhmPi classes should be initiated at a very early stage to investigate the best ways to design and implement a working solution.

If you are dealing with case 1 or have designed a development path and strategy, you are ready to start.

First the hardware board/device should be conceived and designed. The Ohmpi team recommends that contributors design or import their boards within KiCAD and that both schemas and PCB are shared.

When developing a new component Class, always start your development in a new branch. 1- Create a new python file or make a copy and modify an existing similar component file. In this python file Create a new class based on the relevant abstract class of abstract_hardware_components.py. Implement the abstract methods to interact with your hardware. Name the file according to the name of the component. Place it in the ohmpi/hardware_component directory.

2- Create a new configuration file or make a copy and modify of an existing configuration file. In this file describe you system including the new component in the HARDWARE_CONFIG dictionary. Name it config_XXX.py where XXX should be replaced by an expression describing the system. Place it in the ohmpi/configs directory.

3- Create a new script or make a copy and modify of an existing script for testing the component. In this script write python code where you will conduct the tests of the required functionalities of the new component.