2025-06-17 (2*3 UE): Project Work

Group 1: Pressure Sensor, SPS Dreamteam, Edge Detection

Pressure Sensor

Split group

• Hardware specific part

  • Setup Pi

  • Implement prototype (in Python)

  • Create C++ class from it

• Software/Agile part

  Much like the event detector task computes events/edges from GPIO levels 0 and 1, the pressure thing needs to be configured to recognize over-pressure (harming people) and under-pressure (sensor defect).

  The SPS dream team can then consume these pressure events much like it consumes GPIO edges.

  • Define interface for sensor

  • Create mocking version

  • Over/under-pressure detection

    • Write unit tests first

    • Hysteresis of some kind

SPS Dreamteam

Group 2: libgpiod Fiasco

Problem(s)

• WSL does not have libgpiod version 2

  • WSL is of limited use anyway: PCs usually don’t have GPIO hardware, and if so they are unlinkely to be seen from Linux

• VirtualBox/Debian likewise

Solution: Raspi As Development Machine

This is challenging on a Raspi 3!

• vscode’s SSH remote file access consumes an infinite amount of resources ⟶ cannot work from PC

  

• Running a graphical editor on the Pi requires a graphical desktop. This also requires a non-negligible amount of resources but should work.

  I recommend using gedit. Works like notepad++, only better.

Install libgpiod

• Prerequisites

  $ sudo apt install -y automake autoconf autoconf-archive libtool
  

• Get/Build/Install libgpiod

  $ git clone https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git
  $ cd libgpiod/
  $ ./autogen.sh --enable-tools
  $ ./configure --enable-tools --enable-bindings-cxx
  $ make
  $ sudo make install
  

• Build Our Project On Raspberry

  • Use desktop OS version

  • Sync your fork

  • Clone project on Raspberry

    • Possibly copy SSH private key to Raspberry?

  • Build as usual

  • Watch out for libgpiod related warnings