I have a Mendel90 which came in a kit with the Melzi board (Marlin firmware), which works great (in terms of quality of print etc)
There's two things that bug me though:
1) The slowness of uploading to the SD card (which I always do as printing directly from a computer, be it a laptop or a Raspberry Pi, always has the risk of interruptions)
2) Monitoring the printer remotely (again, can cause print issues)
I've read recently about the BeagleBone Black (or BBB ), which only costs £30 or $45. The really cool thing about it is within its ARM processor it has two 200MHz microcontrollers (which they call PRUs) on the same chip. They can communicate via the same memory as the main ARM core, but operate independently - allowing you to run Linux, whilst handing off stepper instructions to a separate real-time MCU (thus not having issue with interrupts). It's therefore a bit like having a Melzi + Raspberry Pi, but with a much faster MCU, and much faster communication between the two.
There's a guy who's created something called a Replicape ('capes' are add-on boards, in a similar way to Arduino shields), but his BOM is $90 (chiefly down to the connectors and stepper drivers, the latter of which seem to be 3x the cost of the ones on the Melzi).
I'd really like to make a such a cape as cheaply as possible, but using the same components as on the Melzi (minus the Atmega, SD card reader+buffer, FTDI). That got me wondering about making in a more generic way - such that you could either plug it into a beagle bone, or into an Atmega-based board?
What would also be cool about this setup is that save for the stepper control (which has to be in ARM assembly, but relatively short), all the rest can be written in a dynamic language like Python.
Just wondering if anyone's actually done any of this? I contacted the Replicape guy, but not heard back.
There's two things that bug me though:
1) The slowness of uploading to the SD card (which I always do as printing directly from a computer, be it a laptop or a Raspberry Pi, always has the risk of interruptions)
2) Monitoring the printer remotely (again, can cause print issues)
I've read recently about the BeagleBone Black (or BBB ), which only costs £30 or $45. The really cool thing about it is within its ARM processor it has two 200MHz microcontrollers (which they call PRUs) on the same chip. They can communicate via the same memory as the main ARM core, but operate independently - allowing you to run Linux, whilst handing off stepper instructions to a separate real-time MCU (thus not having issue with interrupts). It's therefore a bit like having a Melzi + Raspberry Pi, but with a much faster MCU, and much faster communication between the two.
There's a guy who's created something called a Replicape ('capes' are add-on boards, in a similar way to Arduino shields), but his BOM is $90 (chiefly down to the connectors and stepper drivers, the latter of which seem to be 3x the cost of the ones on the Melzi).
I'd really like to make a such a cape as cheaply as possible, but using the same components as on the Melzi (minus the Atmega, SD card reader+buffer, FTDI). That got me wondering about making in a more generic way - such that you could either plug it into a beagle bone, or into an Atmega-based board?
What would also be cool about this setup is that save for the stepper control (which has to be in ARM assembly, but relatively short), all the rest can be written in a dynamic language like Python.
Just wondering if anyone's actually done any of this? I contacted the Replicape guy, but not heard back.