Description A pneumatic tube system based on vacuum cleaners and drainage pipe
Has website
Persons working on Clarity, GeeF, Jdew, Sebastian
Tags Seidenstrasse, silkroad, pneumatic tube
Located at assembly Seidenstrasse
Other projects...


After outstanding success of *Silkroad* (ger. "Seidenstrasse") at 30C3, 31C3 and Camp15, the project will return with *Silkroad V4* at 32c3. This year, we'll do a star topology with no vaccuum cleaners at the nodes. Every station has its own field telephone for announcing capsules, it'll be pulled by a vaccuum cleaner at the central node.

We are current plan includes 2 switching nodes located in the hackcenter and at the first floor (below Hall 1). Multiple exit nodes will be located at the hackcenter for different assemblys (interested? send us a mail!), you can also find exit nodes at "Foyer Hall 1" and "Foyer Hall 2". All switching and exit nodes are capable of sending and recieving capsules to every other station.

In years where net neutrality is important, we had to follow our competitors and provide you some "special services" on our "Datenautobahn". More information later.


There are two types of nodes: switching nodes and exit nodes.

Switching nodes are points where multiple pipes arrive and where people feel like performing the switching functions. Feel free to visit us and help us switching packets (you'll find us, just follow the yellow tubes!).

Exit nodes can be at any place in the building and can be used to send and recieve capsules. We'll provide you information howto send capsules at every station.


Silkroad V4 RC1:

Silkroad Network V1.png

Adressing Scheme

Each exit node is adressed by its switching node designation plus its pipe number. Each switching node handles its pipe numbering as it sees fit. Re-numbering is strongly discouraged, if pipes fail or are shut down, just leave its number dormant.

Naming Convention

The basic adressing scheme consists of the Switch Node Number followed by a : and the Endpoint Pipe Number at this node. e.g. 23: 42 (meaning: switching node No. 23, Endpoint No. 42). A barcode representation of the basic adressing scheme should be developed. Additionally, memorable naming is allowed, at least if the switching node is operated by humans.



Apparently buildup is starting at ~19.12

If you want to help building the Seidenstrasse, do not hastitate to contact us. Try #seidenstrasse on or our Mailinglist seidenstrasse AT

How to make your own capsule

Everyone who wants to participate should build their own capsules. Please post your pictures, drawings, instructions and experiences here as inspiration for others.

Important: Capsules without light will not be allowed in the system! Attach at least one LED to each capsule, so stuck capsules are visible. No exceptions!

Tube dimensions (verified by measurement): Outside diameter: 100 mm Inside diameter (the tube is corrugated): 90-92mm

Capsule properties (verified by experiment):

min max optimal? comment
Diameter 75mm 90mm 85mm also depends on capsule's sides, if soft, thicker may be better
Length 100mm 220mm 180mm too short might cause it to turn and get stuck, too long will not get around corners. (rounded and narrowed ends can be longer)
Weight -10t 550g 250g large weights need to be tested more on long tubes going up

The ends of the capsule should be round or narrowed, so it can easily glide around bends. Take a look at how commercial capsules look like for inspiration:

Do NOT buy commercial capsules. They won't fit!

A capsule made by cutting a ring out of a 85mm 1.5l PET water bottle and putting the ends back together worked really well in experiments (see picture below).

At the largest diameter a ring of felt or the soft side of velcro should be applied to ease the gliding through the pipes and provide a better airtight seal between tube wall and capsule.

Capsule Ideas: Multicolor glowing capsules, capsules with e-paper displays, encrypted capsules (with puzzles or locks).

3D Files

  • [1] by protofALk
  • [2] by LongHairedHacker

How to send a capsule

All Capsules have to be certified with an C5 Certificate (for Capsule Certification call: TBA)

First, write the receiving address on the capsule (optional: return address) or use our address stickers: LINK TBD. Then bring your capsule to the nearest exit node, put your capsule in and call the nearest switching node with the phone provided at the node.

Archived page - Impressum/Datenschutz