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Introduction to the SNAP protocol

IntroductionS.N.A.P. is a protocol for communication between several connected hosts. It provides:· addressing· flags· ack/nak request· error detection (different error detection methods available)It can be run over different media, including RS485. It is optimized for a small footprint (limited computing, memory resources), but scaleable depending upon your needs.Basically, if you want to connect several compute [...]

By | April 23rd, 2019|Development|Kommentare deaktiviert für Introduction to the SNAP protocol

Elektronik-Gehäuse & Platinenabmessungen Standards

Abmessungen Raspberry PiEin Raspberry Pi 3B+ hat, als Vergleich, die Abmessungen: 85 mm x 56 mm für die Basisplatine. (USB & LAN, sowie andere Stecker ragen teilweise über die Platine hinaus). Hutschiene / DIN-SchieneHutschiene: TS35, U-förmiges Profil. Standarisierte Befestigungsschiene für Gehäuse, Racks, Schaltschränke, u.s.w. Sie wird vielfach in der Industrie eingesetzt. Einer der ersten Einsatzzwecke [...]

By | April 20th, 2019|Raspberry Pi Blog|Kommentare deaktiviert für Elektronik-Gehäuse & Platinenabmessungen Standards

Packaging Python projects for Debian / Raspbian with dh-virtualenv

This article aims to explain some things to developers which don’t use Python a lot, and might struggle with some of the concepts otherwise.I highly recommend the lecture of the following article as an introduction to the concepts discussed here:https://www.dabapps.com/blog/introduction-to-pip-and-virtualenv-python/pypi.orgpypi.org is an official repository of software for the Python programming language. It includes libraries we [...]

By | April 19th, 2019|Development, Raspberry Pi Embedded Development|Kommentare deaktiviert für Packaging Python projects for Debian / Raspbian with dh-virtualenv

mongo_orm custom name for collection

mongo_orm will automatically determine the name for your collection by using the Module and Class name, and appending an “s”.In cases where you want to name your collection, you can simply do this:class PapiTest < Mongo::ORM::Document     collection_name "Buster"     field test : String end get "/" do     pt = PapiTest.new     pt.test = "I want your sex"     [...]

By | April 17th, 2019|Crystal Language|Kommentare deaktiviert für mongo_orm custom name for collection

Avahi how to assign several .local names to same IP

In some situations you would like to access the same computer / IP using different .local names.This is possible using the Avahi daemon. The following is written for Ubuntu 18.04 Bionic Beaver.Install Avahiapt install avahi-daemon avahi-utilsAvahi automatically adds your computer’s hostname to the .local Domain. For instance, my computer is called morpheus. Therefore it will [...]

By | April 10th, 2019|Tips & tricks|Kommentare deaktiviert für Avahi how to assign several .local names to same IP

Creating a Raspbian repository

If you want to host your own Raspbian repository, this article is for you.A Raspbian repository consists of a special directory structure on a webserver. The files, including the packages, are all static – therefore this repository could also simply be hosted on an Amazon S3 instance, for example.The sources.list entry in Raspbian/etc/apt/sources.listdeb http://raspbian.raspberrypi.org/raspbian/ stretch [...]

By | April 3rd, 2019|Raspberry Pi Blog, Tips & tricks|Kommentare deaktiviert für Creating a Raspbian repository

TEK-Berry RAL light grey color comparison to official Pi Zero W case

The official Pi Zero W case is white, whereas the default TEK-BERRY sold as white is in reality RAL light-grey – a bit darker than white.Here’s two pictures. When placed side by side you can see the difference, otherwise it is hard to tell that the case is not indeed 100 % white:The cases are [...]

By | März 20th, 2019|Raspberry Pi Blog|Kommentare deaktiviert für TEK-Berry RAL light grey color comparison to official Pi Zero W case

Cancel datafeedwatch subscription / Datafeedwatch kündigen

DataFeedWatch is a very useful tool for generating feeds from your online shop into a variety of targets (e.g. eBay MIP, Amazon Marketplace, Geizhals, other price comparison engines).However some time you may want to cancel your subscription. The link for it is quite hidden. Here’s the way to do it:click on Account (the gears), Plans.Scroll [...]

By | Februar 11th, 2019|Tips & tricks|Kommentare deaktiviert für Cancel datafeedwatch subscription / Datafeedwatch kündigen

Instructions for adding a user to a mongo database for mongo_orm

You don’t want your web application to access the database using your database admin user. Additionally you want it to access only one specific database – maybe you have additional databases running in your mongo instance. Prerequisites:mongo_orm expects the database configuration as environment variables or as a file config/database.yml in your project.The config/database.yml file looks [...]

By | Februar 9th, 2019|Crystal Language|Kommentare deaktiviert für Instructions for adding a user to a mongo database for mongo_orm

Beamer Recherche

Beamer RechercheTechnologienLCDJe Farbe ein LCD Panel, werden zusammen projiziert (Licht wird durch die LCD Paneele hindurchprojiziert)zweitbeste KontrastwerteGut für Helligkeit.Nachteile:· Fliegengitter-Effekt ("screen door effect")· staubempfindlich· LCD-Memory-Effekt (Einbrennen)DLPnutzt kleine Spiegel auf einem Chip, um Licht an / aus zu modulieren.Meiste Modelle haben ein Farbrad um sequentiell Farbe aufzubauen. Einige High-End Modelle haben drei DLP chips (einen für [...]

By | Februar 7th, 2019|Raspberry Pi Blog|Kommentare deaktiviert für Beamer Recherche