mbj: The architecture of the printer looks great. Did you publish the project somewhere? I would like to rebuild it some time.
Crumpy: Back to your question: I can recommend the Anycubic i3 Mega which is some kind of Prusa clone. There any many youtube channels and guides for this printer. It is great for beginners. At the other end there are many upgrade possibilities.
Oh, my first post and I mixed the language
I read so many posts here and totally forgot that they are in english why Iwas posting my post 
Many thanks for translating!
I want to run multiple Arduino sensors ( temperature )and send their data directly to the Raspberry over NRF24. So I have a NRF24L01+ connected to my Raspberry B . I have the NRF24 Libary downloaded from GitHub and I proceeded according to the following howto :
http://forum.mysensors.org/topic/1151/tutorial-raspberry-pi-nrf24l01-direct-connection
However, when I call PiGatewaySerial , it always stops at "check wires"
root@raspberrypi ~ # PiGatewaySerial
Starting PiGatewaySerial...
Protocol version - 1.4
Created PTY '/dev/pts/1'
Gateway tty: /dev/ttyMySensorsGateway
check wires
I have checked the cables several times . The CPU load is at 100 % .
I had already seen this one thread , but found no solution . I have both PINs for CE connected, hardware PIN 22 and PIN hardware PIN 25.