On 28-1-2014 15:33, Charles Steinkuehler wrote:
On 1/28/2014 8:18 AM, Elias Bakken wrote:
Dave, I might be able to shed some more light on this, unless you are
completely set on making your own cape (Which is a lot of fun BTW :)
I am also biased since I have made the Replicape, but I'll try to be
objective and summarize the differences as I see them:
Good job, I think we need web page for this. Who's first? (I'm to biased
since I made the BeBoPr++ ;-)
Dave: I agree with Elias, it's fun to build your own cape. But don't
expect to get rich!
A great comparison, Elias. A few minor comments in-line.
Replicape - BeBoPr++
5 steppers - 4 steppers
On board yes, but with the Penta Stepper board, or with external drivers
the BeBoPr++
board also support 5 axes.
Stepper current programmable by ADC - stepper current adjustable with a
trim-pot.
Microstepping programmable via SPI down to 1/32 nd - Microstepping with
dip switches down to 1/8 th (?)
The BeBoPr uses 3 dip switches, and will support whatever mirco-stepping
is available on your Pololu drivers of choice (ie: 1/16 or 1/32 if the
driver supports it). This is just like the RAMPS or most other common
3D printer shields for the Arduino.
Indeed, there is no difference in microstep options between the BeBoPr++
and the Replicape.
The Penta Stepper driver board also uses software setting of the
microstepping. These DIP
switches are so horribly expensive !
Stackable for LCD3/Reach or similar - Not stackable, but can use the
HDMI/I2C for display.
Low pass filter in analog input - Voltage clams on analog inputs
The BeBoPr++ is meant to be the last cape of a stack. Since some LCDs
also want to be
the last cape, only on of these can be used.
But the BeBoPr provides a firm mounting base for capes and with the LVDS
cape
it's possible to use an LCD with touch, or just use the HDMI output.
There is low pass filtering on the BeBoPr analog inputs, as well as
input protection.
Yes, and even some RAMPS people are now implementing this design :-)
No over-voltage protection on end-stops - ?
All I/O on the BeBoPr is protected and level-shifted, including the end
stops.
Indeed, and the inputs are schmitt-trigger inputs, i.e. have hysteresis
for slow changing signals.
This is a nice feature if you are using optical sensors (e.g. slot
sensors, opto interrupters, etc.).
The BeBoPr++ inputs can also be used as 5V TTL compatible inputs. I'm
not sure about the
Replicape inputs, AFAIK it's inputs connect directly to the BeagleBone.
So in that case, using
5 Volts input levels is not possible.
Open source Hardware, software and firmware - Open source software (?)
$179 - $120 (is this right for the ++ board?) + four stepper boards ($10
each?)
The BeBoPr++ will cost around $99 (depending on exchange rate fluctuations).
-- Bas
Bas has designed an add-on board to drive five steppers called the penta
board:
https://github.com/modmaker/BeBoPr/wiki/Penta-Stepper-Board
...you can also use the header the penta board connects to for driving
off-board stepper drivers if you need more power (for driving a real
milling machine, as an example).
Both are great boards, and which one will work best depends on exactly
what you're trying to do, whether you've got any Pololu drivers on-hand,
etc.
--
For more options, visit http://beagleboard.org/discuss
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