Ubuntu play

I've been setting up Ubuntu 10.04 (EMC2 version) on an old desktop PC to try out EMC2 for mill control and as a general shed PC. The PC was $5 at the tip and I picked up a 15" LCD monitor for $2 at the same time. The monitor does not have a stand so I'll need to fabricate something for that but otherwise works well and has a composite input so I could use it for other purposes.

The CD drive was not working correctly on the PC so I've done the install to the hard drive via a USB/hard drive adapter. That took some fiddling for some reason but it's all working nicely so far.  No attempt to connect it to the mill yet.

I've also fired up Ubuntu One which will let me synchronize nominated folders across any PC I have running Ubuntu 10.04 or higher with an Internet connection.

I've also got Ubuntu installed as a dual boot on my better laptop and one of the very old laptops (currently Debian on the Beagleboard). I'm still running Windows on the other partition of the main laptop and on the desktop PC.

I've not done well with Ubuntu and displaying Powerpoint 2010 files - Libra office will open them but can't get the format right and the Powerpoint Viewer running under WINE can't open them for some reason.

There are also a number of Astronomy app's which I want to use which I've not been able to find Linux equivalents for - EQMOD, telescope guiding software, remote control of a Canon EOS camera etc. There is an Arduino package available but I've not done well with port settings yet.

I've had a basic play with the EOS utility and WINE but have not got it working correctly yet.

Bob

Bluetooth as EQDIRECT for an EQ6 telescope mount

I've posted this on the EQMOD yahoo group and the IceInSpace forums.

I've managed to get a bluetooth connection running to control an EQ6 Pro.

I'll summarise what I've done here while it's fresh for the benefit of others
who are trying to do the same.

Equipment - a couple of ebay items and bit's and pieces from my workbench and the local Jaycar store.

- A bluetooth module
(http://cgi.ebay.com.au/Bluetooth-Wireless-TTL-Transceiver-Module-5V-GND-TX-RX-/\
380319761963?pt=LH_DefaultDomain_0& hash=item588cd3062b) US$15
- An LM7508 voltage regulator
- DB9 male connector
- Micro Bluetooth adapter for the PC
(http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=2004689 96304&ssPageName=S\
TRK:MEWNX:IT) AU$1
- A power diode (not essential)
- One small plastic jiffy box from the local electronics store
- Double sided heat trasfer tape (not essential)

All up parts were just over the AU$20.

To confirm pinout's looking at the back of the male DB9 plug connected to the mount with the row of 5 to the top - 1 is top right, 5 is top left, 6 is bottom right and 9 is bottom left.

DB-9
1 12Vdc - I've soldered a diode into the feed to the regulator. Not essential.
5 - Gnd (Left most of the row of 5 looking at the mount or back of the
connector)
6 to the TX pin of the bluetooth module
9 to the RX pin of the bluetooth module

I've stuck the voltage regulator onto the back of the bluetooth module with double sided heat transfer tape and brought the GND and output pins down to the back of the 5V and Gnd pins on the bluetooth module. I removed the 5V pin from the module and then had to replace it, at a guess the hole is not plated through.

Windows XP mapped 2 ports in the Device setup, an Incoming and an Outgoing. I still have not made sense of that but the outgoing one is the one which worked.

I had some problems trying to get EQMOD recognised in the Ascom driver selector, the EQMOD.Telescope driver didn't have any attributes in the profile Explorer. Adding a name seemed to make it visible to the selector. I need to read some more about that as I may now have that right.

I've now had it running from The Sky and also via a very cheap game controller (http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=1106477 06075&ssPageName=S\TRK:MEWNX:IT). That's not fully configured so don't take it as a recommendation for the controller but it does do the basics.

I want to explore some other bluetooth options, a smallish battery pack and a bluetooth module for the hand controller so I can run wireless without a PC for simple setup's. Bluetooth comm's to an Arduino controlling the focusser(s). I'm also wondering how hard it would be to get the output of a USB hub into a bluetooth transmitter so that camera(s) can be run through the link.

The image is from before the module went into the case.

First pass at an inside curve in the Z axis on the mill

I've been thinking about trying to make a low profile focusser for my Skywatcher telescope for a while. A few things to learn before I'm ready for the whole thing.

One thing I'd not tried before was a curve in the Z axis on the mill. The back of the focusser needs to mate with the outside curve of the telescope tube (350mm diameter).

The standard focusser has a base plate around 110*110mm square. I cut a piece of aluminium almost that size out of some scrap and set up the code to cut the curve.

The code aspect is pretty simple, I used the G18 (XZ plane) element then worked my way back and forward along the material using G2 and G3 cut's with a radius of 175.

The cutting commands are in two subroutines
(---------------------------------------------------)
(Cut the Arc)
O0001
G01 Z0 F30
G02 X108.5 R175 F25
G90 G00 Z2
M99
(---------------------------------------------------)
(Cut the Arc)
O0002
G01 Z0 F30
G03 X1.5 R175 F25
G90 G00 Z2
M99
(---------------------------------------------------)

and the main body contains a whole lot of sets of move in the Y axis and start a subroutine commands
G00 X1.5 Y0
M98 P1
G01 Y1
M98 P2
~~~~~

G01 Y105
M98 P1
G01 Y106
M98 P2

I used a 3mm cutter on fairly slow feed rates so it took a very long time to cut (and I still need to do a final cut) but the result looks as expected (I'll try and post a photo in the near future).


The surface is composed of a series of small groves due to the shape of the cutter, I don't think that they will cause me any problem.

Astronomy Dew Controller and the Arduino

I posted the details of a dew heater controller I built on the IceInSpace site some time back.

http://www.iceinspace.com.au/63-597-0-0-1-0.html

Based around an Arduino, a two-wire temp/humidity sensor, one-wire temp sensors and a Sparkfun serial LCD controller.

Small stepper drivers

I've tended to use the Sparkfun Easy Driver (http://www.sparkfun.com/products/10267) to drive small stepper motors.

I'm working towards trying out the Trinamic TMC223 IC (http://www.trinamic.com/tmc/render.php?sess_pid=394) which use a 2-wire ( http://en.wikipedia.org/wiki/I%C2%B2C ) protocol instead of the more common step/dir pins and which also has stall/missed step detection. I've used 2-wire temperature/humidity sensors previously in dew controller's I've made for controlling telescope heater straps.

If the IC's do what they appear to be set up for they should be great for application such as focusser control and possibly very small CNC setup's (stall/missed step detection would be a big bonus for both).

The additional components required to use the TMC223 seem to be very minimal.

CNC - what I'm working with

My CNC mill is a Seig X1 mill that's I've fitted out with some 3A Nema23 Stepper motors and a 4 axis Chinese driver board (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180558342384&ssPageName=ADME:X:AAQ:US:1123).

I'm driving it from a very old HP laptop and Windows XP. The laptop has a parallel port. Currently using the free version of Mach3 and hand coding my gcode scripts.


I've added coolant lines. No ball screws etc at this point, the price does not seem to be justified yet. I'm using a drill vice to hold the workpieces until I make a longer term decision.

Cutters have generally come from CTC tools (http://www.ctctools.biz/servlet/StoreFront) - so far so good.

At this stage I've been very happy with the result's. It's got me started in CNC for a relatively small outlay and I seem to be able to make small parts with good accuracy once I get the code right.

I'm looking into moving over to Ubuntu and EMC2 for the software side of things but I still need to learn a bit more yet.