Blockchain-powered Christmas trees are popular this year. Two separate teams of developers, one funded by Nano, and the other at the University of Ljubljana in Slovenia, offered interactive trees this month, with lights that can be replaced through a blockchain donation.  

The projects are real-world examples of how real things can be managed through a mere blockchain interface. They illustrate the technology’s power besides smart meters and the Internet of Things (IoT) and are created to promote understanding and approval.

The Ethereum Christmas tree

The Ethereum powered tree is located in the lobby of the University of Ljubljana’s Faculty of Electrical Engineering.

“It’s a working prototype the students can use,” the project’s leader Matevž Pustišek told Decrypt. 

“We provided a simple web user interface. You can open it on your mobile phone or another device, and then you can select the colour of the lights and the period [of time] the lights should go on for. In the background, it executes an Ethereum transaction which is accepted by a smart contract,” he said.

The smart contract is made of a device dubbed Swether, an IoT gadget produced by the team to manage the lights. In principle, Swether prevents events from the Ethereum network and toggles its state, respectively. Someone who has the link to access the site can examine the tree. However, since the team has yet to install a webcam, there’s no method to see the result unless you’re in the lobby. The Faculty currently supply donations.

Nonetheless, Pustišek thinks that it’s a good starting point for students to produce decentralized applications such as applications for the smart grid or charging points for mobiles and electric cars.

The Nano Christmas tree

To change the lights on the Nano powered Christmas tree, you can give Nano donations applying a QR code through a simple interface. The last digit of the sum sent directs what the lights will do. There are ten distinct program patterns to try out.

This project is an alliance between the Nano Center and the Pixel Bar. Nano Center funds the blockchain’s initiatives. Funds will be donated to Simon on the Streets, a charity that supports the homeless of Leeds get back on their feet. 

“We developed this to show that you could have a fun and engaging way to drive donations for charity by having something cool and innovative tied to a simple donation,” one of the developers on the project posted on Wednesday, on Reddit. “We’ve raised approximately £500 for Simon on the Streets, and hopefully delivered some holiday cheer along the way as well.”

 Nano consolidates blockchain technology with a Directed Acrylic Graph (DAG), a structure that examines individual transactions directly connected rather than grouped for processing in blocks. According to Nano, when dedicated Nano wallet ‘Natrium’ is utilized for the transaction, the tree lights change in 170 milliseconds.