Submitted by RCFisher on Thu, 06/03/2010 - 22:42
Posted in
Hi Church
I was going over my ideas for my moco setup. Right now I am going to use S/D for 4 motors and the camera F/S lines, I also wanted to incorporate the LCD interface but it seems that I am running out of lines since the LCD needs one TX digi line and 5 more analogue for the buttons. I would also love to have an emergency stop and limit switches for the dolly. Doesn't that use all the lines of an Arduino Duemilanove? Maybe I should start thinking about going to a Mega board.
I like the idea of having an onboard UI available for simple moves.
As for the sleep line, I am using the Pololu A4983 stepper driver could I just wire the limit switches in series to the disable pin & gnd on that board or should that be wired to the sleep pin on the OM/Arduino board?
Or should I just keep it simple for the moment and build a Mega controller later? I have an Arduino Duemilanove at the moment.
thanks
OOPS I just found the diagram
OOPS I just found the diagram for the Pololu driver and it has both sleep and enable pins.
RC, you should focus on
RC, you should focus on getting it up and working first - and then worry about expanding later. =)
There are enough pins to run the 5 buttons, the LCD, and everything combined (except Alt I/O) on the Duemilanove. It will require a slight re-arrangement, but no worries about that right now!
I generally don't trust software-based limit switches. Best to use an AND gate between a normally pulled-high limit switch (switch should connect to GND when tripped) and the 'step' lines. That way, if you hit a limit, you won't keep moving and no worries about a software screw-up taking too long to turn off the motors or even a bug causing major damage. Same for e-stop.
The 'sleep' line was set to be shared between all drivers - just connect all axis that you want to go to sleep between moves to it. Then use the kill command in slim to control it.
!c
Hi Church I figured the pin
Hi Church
I figured the pin assignments would need rearranging. There may be a pin left over for the Alt IO. Anyway if I can get to it this weekend Arduino/OM time. Consumed by other stuff last weekend.
After checking the docs for the Pololu driver I need to figure that out. S/D and sleep seem pretty strait forward but setting up the other stuff not so simple, for me anyway. My Gecko drivers were really simple. Not quite sure how to set up the microstepping but I think I can ask about that on Pololu's forum.
Onward
Thanks