Milling machine plans for Tues 9 March
michaelc
evening, and perhaps even get movement out of the two axes for which
we have stepper drivers.
This is my suggested list of activities, some of which can be done in
parallel if there enough people interested:
- Connect the LCD to the controller board (has this already been done,
and if not do we have the appropriate connectors available ?).
- Build a PCB or cable to adapt from a normal AVR-ISP header to the
connector on the controller board.
- Determine the wire order at the stepper motor driver output by
attempting to drive a motor with the firmware Mitch wrote when we were
using the machine to drill holes. I've got a set of test clips to help
with this.
- Assemble the wiring into the controller side breakout board. The
controller to breakout board connections are done, but the stepper
driver connections are not. I've crimped pins for the molex connectors
onto wires, but left them out of the housing for now because I don't
know the correct wire order.
- Attach the emergency stop button to the machine, and check with a
meter that the signal reaches all the way back to the controller board
when the button is pressed.
- Check photo-interrupter operation with a meter.
- Power up the controller without connection to the machine (with
emergency stop tied low/inactive) and check that it responds to
commands from a PC.
- Attach the controller to the machine, and attempt to drive 2 axes.
I've started at work early today so that I can leave early, and will
be at the Hackerspace meeting early (hopefully between 6 and 6:30pm)
but will need to leave early too.
These are the parts I plan to bring with me tonight - if I've
forgotten anything it's probably too late now, but tell me anyway:
1) controller side breakout board
2) programmed micro for the controller board
3) emergency stop button and box
4) DB25 - DB25 cable
5) wires from the controller to the breakout board
6) wires from the stepper drivers to the controller board
7) AVR-ISP programmer
Michael
Luke Weston
>
> - Connect the LCD to the controller board (has this already been done,
> and if not do we have the appropriate connectors available ?).
All already done - nothing to do, no components required.
> - Build a PCB or cable to adapt from a normal AVR-ISP header to the
> connector on the controller board.
There is no ISP header on the board. The chip needs to be put on a
breadboard or some other similar arrangement.
> 4) DB25 - DB25 cable
I propose that it may be better to use a ribbon cable with IDC D25
connectors as opposed to a off-the-shelf standard computer hardware
style cable - there will be less intra-wire crosstalk or interference
with a ribbon cable.
> 5) wires from the controller to the breakout board
> 6) wires from the stepper drivers to the controller board
All this wiring is already implemented. The wiring looms between the
controller board and the stepper driver boards are all already done.
There is a cable with a molex header plugged into the controller board
and unterminated at the other end. This connects to the terminal
blocks on the D25 breakout board.
michaelc
On Mar 9, 5:15 pm, Luke Weston <reindeerfloti...@gmail.com> wrote:
> > - Connect the LCD to the controller board (has this already been done,
> > and if not do we have the appropriate connectors available ?).
>
> All already done - nothing to do, no components required.
>
Excellent.
> > - Build a PCB or cable to adapt from a normal AVR-ISP header to the
> > connector on the controller board.
>
> There is no ISP header on the board. The chip needs to be put on a
> breadboard or some other similar arrangement.
>
I must be reading the wrong schematic (there's a few to choose from on
github). The one I've been looking at has all the programming pins
brought out to JP6. If that's not present, I'd better get a boot-
loader onto the chip. That will have to wait until next week.
> > 4) DB25 - DB25 cable
>
> I propose that it may be better to use a ribbon cable with IDC D25
> connectors as opposed to a off-the-shelf standard computer hardware
> style cable - there will be less intra-wire crosstalk or interference
> with a ribbon cable.
It might be, but I don't have the parts handy. Given the nature of the
signals involved there's a risk but it's probably OK even with the
stepper drive on the same cable given that the signals back to the
micro are very low frequency solid TTL levels. All the same, we can
take a look on the scope and see if there's a worrying amount of
noise. If we find a problem, we'll fix it.
>
> > 5) wires from the controller to the breakout board
> > 6) wires from the stepper drivers to the controller board
>
> All this wiring is already implemented. The wiring looms between the
> controller board and the stepper driver boards are all already done.
> There is a cable with a molex header plugged into the controller board
> and unterminated at the other end. This connects to the terminal
> blocks on the D25 breakout board.
Cool. The wiring from the controller board to the breakout board has
been implemented twice then. We'd better build another machine quickly
so it doesn't go to waste.
Luke Weston
> I must be reading the wrong schematic (there's a few to choose from on
> github). The one I've been looking at has all the programming pins
> brought out to JP6. If that's not present, I'd better get a boot-
> loader onto the chip. That will have to wait until next week.
>
You're actually completely correct, I forgot about that. There is no
standard 6-pin or 10-pin ICSP header, though.