Bad News!


Unfortunately we have bad news for the Teebeutel badge: We cannot offer the badge as planned this year. The costs for electronic components, production and transport have risen again in the past weeks and made the price so high that we had to decide against a production for this year. However, we will continue to develop the badge and offer it at a later point.


Beim Teebeutel-Badge haben wir leider schlechte Nachrichten: Das Badge können wir leider nicht wie geplant dieses Jahr anbieten. Die in den letzten Wochen nochmals gestiegenen Kosten für elektronische Bauteile, Fertigung und Transport haben den Preis so hoch steigen lassen, dass wir uns für dieses Jahr leider gegen eine Fertigung entscheiden mussten. Wir werden das Badge jedoch weiterentwickeln und zu einem anderen Zeitpunkt anbieten.


Teebeutel (eng. Teabag) is an electronic, Entropia themed con-badge for the GPN20, featuring an ESP32 microprocessor running micropython. You can tinker with its various sensors, build your own custom expansions, render beautiful animations on the 128x128px oled or simply enjoy it as the colourful badge it is. Plenty vivid LEDs will give you room to stand out within the crowd. Keep on reading to find out what else this badge has to offer, how to use it and get answers to your questions.

We are currently searching for hackers! You want to get your hands on a Teebeutel before anyone else and help us with software, beta-testing and design? Now is your chance: Continue reading
Some Tebeutel PCBs


This Project wouldn’t be possible without commercial sponsorships.


Thanks to PCBway for the 50% discount on PCB manufacturing and assembly!

PCBway Logo

OSHWA Certification

Every part of this project is opensource and OSHWA certified!

You can…​

  • …​ freely contribute to this project!

  • …​ build your own Teebeutel!

  • …​ customise and expand Soft- and Hardware easily!

  • …​ build new Hard- and Software based on this project!

To make upgrades and add-ons of the Teebeutel as easy as possible you can use the expansion-port on the back!

OSHWA-IDs: DE000119 DE000117


You have 12 side-facing RGB LEDs (ws2812b-4020) at your fingertips that can produce awesome light effects! They’ll perfectly fit with the (nightly) glow of the GPN!

A PCB with 12 RGB leds around its edge glowing in rainbow colors in front of a white background.



An SpO2 sensor measures the oxygen-concentration (in %) in your blood as well as the pulse. This is all done non-invasive, just by laying your finger on the sensor. This is the most common sensor you find in hospitals and emergency services will utilize these sensors.

A typical pulse oximeter uses an electronic processor and a pair of small light-emitting diodes (LEDs) facing a photodiode through a translucent part of the patient’s body, usually a fingertip or an earlobe. One LED is red, with wavelength of 660 nm, and the other is infrared with a wavelength of 940 nm. Absorption of light at these wavelengths differs significantly between blood loaded with oxygen and blood lacking oxygen. Oxygenated hemoglobin absorbs more infrared light and allows more red light to pass through. Deoxygenated hemoglobin allows more infrared light to pass through and absorbs more red light. The LEDs sequence through their cycle of one on, then the other, then both off about thirty times per second which allows the photodiode to respond to the red and infrared light separately and also adjust for the ambient light baseline.
— https://en.wikipedia.org/wiki/Pulse_oximetry#Mechanism
This is not a medical device!

I²C: 0x5B

Air-quality, CO2, Ethanol

With this sensor can measure gasses in the air. With these measurements an air-quality score is calculated.

I²C: 0x58


This is probably one of the most common sensors as pretty much every smartphone has one. This sensors measures acceptilational forces (therefore gravity too). This way you can measure how the Teebeutel is oriented in space.

I²C: 0x32

Hall sensor

The hall sensor is iterated into the ESP32. It utilises the electromagnetic hall effect to measure the strength of magnetic fields nearby.







IR Transceiver


Programming-Interface and Power

This connector is not a network connection! Connecting Ethernet, especially with PoE(+), might break the UART interface.

You can charge and connect a serial-terminal for firmware- and app-uploads as well as debugging via the RJ-45 connector. You can use the following diagram to create your own cable, or use the one that was provided with your kit.