Note to self 1. PCM state (snd_pcm_state_t) [1] SND_PCM_STATE_OPEN SND_PCM_STATE_SETUP SND_PCM_STATE_PREPARED SND_PCM_STATE_RUNNING SND_PCM_STATE_XRUN SND_PCM_STATE_DRAINING SND_PCM_STATE_PAUSED SND_PCM_STATE_SUSPENDED SND_PCM_STATE_DISCONNECTED State Machine [2] References [1] snd_pcm_state_t [2] ALSA project – the C library reference
This post shows a way to generate a UML class diagram from C++ header file(s) using PlantUML [1] and hpp2plantuml [2]. Assumptions Debian-based linux distribution (I used Ubuntu 20.04) Steps 1. Install hpp2plantuml hpp2plantuml is used to convert C++ header file to PlantUML. 1-1. Install pip if not already installed. sudo apt install… Continue reading “Generating UML Class Diagram from C++ Header File using PlantUML”
This is an example of minimal tkinter application that shows video image on the window using OpenCV. Prerequisites Python 3 Required Packages Install packages if not already. 1. Python Imaging Library (Pillow) pip install Pillow 2. OpenCV pip install opencv-python Code import tkinter as tk from PIL import Image, ImageTk import cv2… Continue reading “Showing Video Image on Tkinter Window with OpenCV”
This post shows steps to create an AltBeacon [1] with Raspberry Pi, by modifying BlueZ BLE Advertisement example code (i.e. “example-advertisement“). *If you want to create Apple’s iBeacon [2], please see this post. Prerequisites (parentheses indicate my environment) Raspberry Pi (Raspberry Pi4 B with Raspbian Buster 2019-06-20) Internet access To download BlueZ example code. Here… Continue reading “Creating AltBeacon with Raspberry Pi using BlueZ Example Code (updated)”
This post shows steps to create an iBeacon with Raspberry Pi, by modifying BlueZ BLE Advertisement example code (i.e. “example-advertisement“). Note: Even though it uses Bluetooth Low Energy standard, iBeacon is Apple’s proprietary protocol and making/deploying iBeacon devices requires the license from Apple [1]. The scope of this post is limited to getting familiar with… Continue reading “Creating iBeacon with Raspberry Pi using BlueZ Example Code (updated)”
