Walking the dog.

A project log for Arcus-3D-C1 - Cable 3D printer

3D printable, Open Source Hardware, tripod kinematics, cable driven 3D printer

Daren Schwenke 10/20/2017 at 23:390 Comments

I'm a fan of the Beaglebone.  

You can get down and dirty with hard-realtime assembly level control of pins if I you want, or watch from 10k feet and twiddle a pin in web browser with just Javascript.

I sum up the Beaglebone Black to people who have never heard of them with the following blurb.

Take a normal Linux computer running on a cell phone processor, and tie it in memory to two Arduino's running at 200Mhz with 60ish IO pins and single clock cycle operations for most of them.  There is also hardware PWM, SPI, I2C, Ethernet, etc you can enable, but the former lets you mock up pretty much any of those devices *from scratch* if you care to get your hands dirty.

It was a beast when it came out, but it was more expensive than the Raspberries and harder to work with.  It's aging now and the fact to access the raw power of the PRU's, you needed to program them in assembly has kinda limited the adoption.

I'm still a fan.

The BBGW is perfect for this printer.  It has mimo (multiple in, multiple out) wifi built in so you can connect it to your normal wifi, or even connect to your normal wifi through it by using it as a gateway.

I'll be doing that running a remote interface for Machinekit which gives me a true trajectory planner, and it also has the assembly bits needed to use the PRU to twiddle the pins.  I'll get hard-realtime control of my steppers.

But the cape I need for this doesn't exist.

All the later capes tended to avoid demanding the HDMI pins on the Beagles as that meant you would have to disable HDMI to use them.

All except for one of the earliest ones, the BeBoPr cape.

The BBGW doesn't have an HDMI chip, but it does have that neato wifi chip.  Problem there is it consumes many of the same pins which the rest of the capes used for motor control and such.

But not the BeBoPr as it stepped on HDMI mainly, except for one pin.  

So I'm starting with the pinout for the BeBoPr and moving that one pin. 

Should be pretty simple.  Soldering iron in hand...