Fighting with computers

Computers are not always friendly.

Sunday, November 18, 2012

Driver update

A few days ago I learned in the RepRap forum about a new stepper driver from Pololu using the DRV8825 from Texas Instruments. I have read good things about this family of drivers being more robust and higher current than Allegro A4988. Well, thanks to the kind offer from Pololu I've got a few units for testing (at a huge discount) and my first impression is pretty good.

This may well be the answer to get a direct drive extruder that does not suck. I have detailed in past posts how I was unable to get a successful direct drive extruder working in my system, as I was needing more current that my electronics were capable of, for my extruder to work reliably at medium speeds. This new driver seems to be able to push 1.5A without the need of active cooling. The manufacturer claims that up to 2.5A per coil are possible with proper cooling.

Next stop is to use them for powering a CNC machine with beefier nema23 motors.

Tuesday, November 13, 2012

Stellaris ARM Cortex-M4F kit

When I saw this summer that Texas Instruments was giving away ($4.99 shipped is a steal) Stellaris boards sampling their Cortex M4 with floating point unit I thought I could not go wrong, as it was already cheaper than any other kit I have bought in my life. After a while I've received a big box at home, than contained a smaller box, that eventually had the small card and USB cable inside.

The first impression was very good. But once I've got the board up and running I wanted to start making some sample programs for testing its capabilities. There is where I felt a bit dizzy. Texas lists a lot of tools to be used, some can be downloaded from their site, others are free versions of commercial products with a limited functionality.

I guess  that these years using Arduino have spoiled me, as  I have been able to complete different projects without having to have a look at any AVR datasheet. Even worse, I get used to the idea I could be developing code in different platforms (Linux, OSX and Windows, though I avoid the latter).

After a registering as a user in TI site, I downloaded a big piece of software called StellarisWare I was expecting to be an easy starting point for testing some examples. It was a Windows-only software that after installing it on a Windows 7 Home Professional would tell me the software might have not installed properly ... (?). I saw no new icons in my start menu and no indication as to what to do next or how to proceed. So at the moment and after using more than one hour of my time I have no clue on how to develop, compile and upload a test program onto this nice board. I guess when I have more time to spare I will give it a second try, but till then, I am a bit disappointed TI is not making lazy developer's life easier.

But if you are like me, this video will make a difference: