Raiden Train Demo

A model train is traveling the world (in our case it's just a circle but hey we all have fanatasy ;) ). During its travels it passes multiple tollgates asking it to pay for the next section. The train however has a Raiden node on board and an open payment channel with it's home toll station. Since the tollgate mafia knows eachother they all have paymentchannels among them in such a ways as displayed in Image 1
Image 1 - Network Topology
With the Raiden Network the train is now able to pay each and every tollgate on it's travel in real time, without the need to stop at any point in time.

Setup on the "main" Computer

The "main computer" is a UDOO x84 Ultra. It has an embedded arduino 101 which is used to control the train's power supply. Therefore the arduino listens to the serial input and gives 3,3V to the GPIO pin 3. This switches the High speed switch on. As soon as the the 3,3V are set to 0V the switch turns off and the train doesn't get any power anymore. A circuit diagram like illustration can be found in Image 2 - Cicruit Diagram.
The UDOO runs all the raiden clients for the "tollmafia" in a virtualenvironment with all dependencies provided in the requirements.txt.

Setup on the Nanopi

The Nanopi has a Raiden Service in /etc/systemd/system/raiden.service.
It runs a raiden light-client as service.
The nanopi uses a virtualenv called "demo" to run the train's logic python ./sender_main.py.

Blockchain Setup

Right now the demo uses the Kovan Testnet.
All accounts hold a certain balance of "Raiden Demo Tokens". The Raiden Demo Token as address is 0xDe99085F789f99568f891c6370fB6b7dD4C90323 and it is a minimalistic standard ERC20 Token. The channels as illustrated in Image 1 are all "unidirectional" with a balance of 1000 and a timeout of 500.

Processing Setup

Processing is used for the frontend visualisation part. All processing files are located in ./processing/sketchbook/ The main file is called railTrack.pde

Start processing without IDE

./processing-3.4/processing-java --sketch=/home/train/processing/sketchbook/railTrack --force --run

Be aware that just the folder is passed and not the actual pde-file.

Run the demo

Udoo

You can login to the udoo via ssh train@demo if you're in the bbot wifi, the password is raiden.
The ~/.bash.rc is configure to autmoatically activate the required virtualenv and navigate to the demo repo
There are several options to run the demo.

1. The first option is to mock raiden hypercorn "webserver:build_app(mock='raiden')"
2. The second option is to run the actual demo hypercorn "webserver:build_app(config_file='raiden_config.toml')"\

NOTE: It is required to reboot the Udoo after stopping a demo run. In theory just a master reset of the arduinio is required, but as this is not physically possible the UDOO developers implemented a master reset of the arduino on every boot of the UDOO.

RPi

You can login to the RPi via ssh pi@raspberrypi if you're in the bbot wifi, the password is raiden.
To start the sender logic on the RPi activate the virtualenv workon demo and execute the sender_main.py python ~/demo-train/sender_main.py.

Debugging

• For the majority of Raiden related issues the deletion of the raiden datadir proved to be sufficient rm -fr ~/.raiden.
• Sometimes the Raiden nodes on the Udoo crash during bootup. This can be checked by running top and see if there are 6 raiden instances active. If not reboot the UDOO and retry it
• Sometimes the connection to the Arduino breaks. Either because of a missing restart or because of the arduino not responding to the serial port anymore. This can be fixed by shutting the UDOO down and turning off the power supply for ~10s.