In order to solve this riddle, you should have the gadget in front of you.
The solutions to the riddles will always involve the gadget somehow. You will have to "do something" with it in order to proceed to the next level.
Once you have done the correct thing, a levelcode will appear below the current Level indicator.
The levelcode is the name of a new page within this website so add the found levelcode to the URL like so:
elektro-maschine.com/levelcodeX.html
Replace "levelcodeX" with the code which is displayed on the gadget.
Good luck!
Now to the first riddle:
Kozuki Nakama Matsuda Ishihara Code
A=^ A=A B=> B=B C=< C=C D=v D=D