We have been moving with all our stuff since December 2023. Our new location is the Stadtwirtschaft. Unfortunately, we are therefore unable to offer an open workshop for the time being. Visit our homepage regularly to find out the latest news from us.

Online Tools

We largely use free open source software to manage ourselves. We consider free, open-source software (FOSS - "free open source software") to be important and expedient, because it means that we can work together and openly on goals and solutions, largely without vendor lock. We can share a few things from our digital valley with you.

Matrix + Element

Matrix is an open standard for interoperable, decentralized real-time communication over IP that provides support for group chat, file transfer, voice and video calls, integration with other apps, bridges to other communication systems and much more. It is used to power instant messaging, VoIP / WebRTC signaling and Internet of Things communication. Element is the popular reference client for using the Matrix protocol.

We have been using Matrix for the association since 2019. Our #hallo chat group can be found here.

The following servers are in our whitelist and activated for federation:

Your server is not listed? Then write us an email!


HedgeDoc (formerly known as CodiMD) is a web-based, self-hosted, collaborative Markdown editor with open source code.

It can be used to edit notes, diagrams and presentations together in real time. All you have to do is share the link to your note with your colleagues and you can start writing together.

Further details on the project can be found on the HedgeDoc Homepage.


Excalidraw is a virtual collaborative whiteboard tool that makes it easy to sketch diagrams that feel like hand-drawn. The boards created can be shared and/or downloaded and imported again later. The data is encrypted end-to-end.

What happens to your data?

The JSON/ROOM data is all stored on our server, but is anonymous and encrypted. We only see when and how many drawings or links were created. Older files that were created more than 365 days ago are automatically deleted. If you want to keep your drawing, simply create a new share link and use it in future. By creating a new link, you automatically create a new data record!

We use the free version of Excalidraw. There is a Plus version that allows much more. The information can be found at


Gitea is an open source versioning system based on the git protocol. It works in a similar way to the well-known giants such as Gitlab, Github and Bitbucket. However, it is free, fast and can be installed on pretty much any platform. We started using it on a small single-board computer called Odroid XU4 (Xubuntu operating system) with an external 256 GB SSD hard disk. However, the need for resources and backbone has recently increased somewhat, so the service has moved to a faster V-Server.

We check out various projects on Gitea, for example to publish source code (e.g. MightyScape) or to manage our hardware - this includes our 3D printer configs. The repository for our Hangprinter implementation called Trikarus has also ended up here.

Gitea is a great way to share and collaborate on open source software, hardware and knowledge, and you hardly want to do without it.


PeerTube is similar to YouTube. But it's much cooler because it's neither mainstream nor ad-supported - it's self-hosted and decentralized. PeerTube is open source and licensed under AGPL v3.0. It is developed by Framasoft. We have been running our own PeerTube instance since mid-2020 and have found a good way for us to visually document our projects and the knowledge stored in them without getting on our or your nerves (ad-free). Without cookies and only saving and finding what is really wanted - this is the desire to regain control over a centralized Internet of consumption. The core of PeerTube is resource-saving, federated and adapts to the download rate of the end user. When bandwidth is low, the service automatically switches to lower resolution streams so that videos can still be played smoothly. PeerTube is based on the ActivityPub protocol, which is also used by systems such as Mastodon and Nextcloud.

You can find more details about PeerTube at and


Organizing events made easy: appointment scheduling with Framadate makes it possible to jointly determine the location, date and time of a meeting. Framadate is a FOSS product from the French organization Framasoft. This organization stands for the development and provision of services that strive for strong ethics and decentralization. Behind a service like Framadate is a political proposal: exploring an alternative to surveillance capitalism by experimenting with the contributory society.

More details about Framadate