Raspberry Pi 3D printers

Tim,

I found your post on this forum and it raised an interesting question for me:  Could I use a Rasberry Pi to make the 3d printers we sell stand alone (printing without a computer attached)? 

Currently, there are stand alone solutions for 3d printers that use the Arduino controller, or the Sanguinololu controller (which is what we use).  Both of these boards use an Atmel Atmega chip.

I did some research into this idea.  The main problem I ran into was that the Rasberry Pi would have to have some kind of breakout board to run the stepper motors, and run the MOSFETs that heat up the print bed, and hot end.  It also needs to monitor temperatures of both as well.   Currently, these tasks are done by the controller boards I already mentioned.

The second problem I discovered is that the Pi is not so good for real time control (timing issues).

The problem with the controller boards I already mentioned is that they don't have good on-board memory (though there are add-on modules for SD cards), and they don't have built in networking, not  Wifi nor wired ethernet.  Of course the Pi excels at this.    The Pi can buffer the GCode being sent to the controller board.  No need for special add-on modules for the controller board, which are not ideal anyway, as they are somewhat expensive and they don't give you a display of any type (yet another add-on module is needed for a simple alphanumeric 2 or 3 line LCD display). 

So, here is the best approach to using  a Pi on a 3d printer:  Use it in conjunction with one of the controller boards I mentioned above.  In essense, the Pi would replace the external computer that the controller board is plugged into via USB.  The Pi could run Pronterface (a 3d printer interface application written in Python), and it would send the GCode to the controller board as it buffers.  The Pi can be hooked up to a real keyboard and mouse and computer monitor and no rinky-dink LCD display is needed.  You will need to add a USB hub of course, because the Pi must send commands to the controller board via USB.  Although, an even cooler idea is to come up with a web interface, and tell the Pi what to do via a remote computer via the network.

Unfortunately, this sort of blows your budget out of the water.  In reality, you budget would not even get you a barebones RepStrap (bootstrapped RepRap).  You have to buy a controller board with stepstick drivers, at least 4 NEMA 17 motors (and preferably another so you have 2 motors on Z-axis), heat bed, hot end, power supply, hardware, frame materials, printed parts to assemble the frame and moving carriages, and so on.  Just buying this stuff will cost you well over $200.

And all of this is going the conventional route, and not using a Pi.

Wow! Great answers, which must have taken time to write... and it appears on the first page on Google! Thank you very much for all your help!

Wow! Great answers, which must have taken time to write... and it appears on the first page on Google! Thank you very much for all your help!