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1  Using Arduino / Programming Questions / Re: Arduino IDE, Wiring, Processing, Firmata relationships? on: August 04, 2012, 05:49:08 pm
Dang good question... I'm a little fuzzy on parts of this myself, but I'll take a stab at it.

Browsing through the various entries on Wikipedia for them... it looks like Processing was first, using a simplified version of Java for programming and GUI.  Wiring derived from the Processing IDE, and uses C/C++ to access hardware.  Arduino appears to be essentially Wiring specific to a particular hardware platform.

So... it looks like Arduino would be what you want for communicating with hardware, and Processing as an option if you want to create a GUI interface for it (although other options such as C++/QT or Python/QT also exist).

Hopefully someone more experience can chime in and correct any more heinous errors in the above... smiley-wink
2  Community / Website and Forum / RSS feed? on: August 04, 2012, 12:55:51 pm
Any chance of getting an RSS feed for new posts or active topics?  Is this functionality already existing and I'm just missing it?  Given that there is a fair amount of traffic here, it would certainly make life a little easier in terms of being able to plug into a feed reader.

Thanks,

Monte
3  Using Arduino / Project Guidance / Re: Controlling scale and trickler on: July 28, 2012, 12:27:03 pm
So I wouldn't need other pins for 'CTS' and 'DTR' as shown in the interface manual?

Actually what I had in mind originally was just using the 25 pin to 9 pin cable and serial-to-usb adapter and having the arduino access the scale via the usb (com) port... is that not viable, or is using i/o pins on the board preferable?  As you can probably tell, I'm learning as I go here - no real hard-n-fast preconceived notions smiley-wink
4  Using Arduino / Project Guidance / Re: Controlling scale and trickler on: July 28, 2012, 11:58:03 am
Interesting wrinkle... thought I had a serial-to-usb adapter here at home. Turns out I *do*, but its for 9-pin serial, not 25 pin (which is what the scale uses).  I know the place I bought the scale from sells cables and adapters and whatnot... found out that this brand of scale, for whatever reason, uses a non-standard pin-out.  Anywho, got a cable with the correct setup and adapter on the way.
5  Using Arduino / Project Guidance / Re: Controlling scale and trickler on: July 28, 2012, 12:55:55 am
Tom,

In the process of browsing various threads in the forum recently I did see a few that mentioned LCD screens, and I've seen mention of SoftSerial as well.  Good to hear from someone else who has used them to implement something similar.

I think it will be educational just to hook up to the scale w/ a computer and see what its actually outputting.  The documentation I've browsed seemed to indicate it did just about what you described... I'm kind of unclear on how often it updates the weight info, and how I would use that to control the trickler.  I mean, I do in kind of the 30,000 foot view kind of way - probably PID or something similar to get close to target weight quickly, then slow down as it gets closer to prevent overshoot? - but actual how to make that happen... is going to be interesting. 

Got a ways to go before I get to that point, though.

Thanks,

Monte
6  Using Arduino / Project Guidance / Re: Controlling scale and trickler on: July 27, 2012, 03:34:44 pm
Nope, Sartorius GD-503

Using pretty much the same setup - GD-503 scale, Lee Perfect powder measure, and Omega two-speed electric trickler - as shown in the linked video. 

Scale is accurate to +/- 0.01 grain; displays to 0.005 gn.  The volumetric powder measure dispenses probably +/- 0.3 gn over the long term with a medium 'stick' (extruded granule) powder.  Individual kernels weigh approximately 0.02-0.03 grains.

Might have to consider other options for the mechanical aspect of bulk powder dispensing; there are devices out there that translate a linear (up-down) motion to the rotary motion (up, down) of the handle on the powder measure.  Measures using linear slide bars tend to not be very consistent as compared to rotary drum devices.
7  Using Arduino / Project Guidance / Controlling scale and trickler on: July 27, 2012, 12:38:36 pm
Right now I'm manually dispensing (using a volumetric measure) into the scale pan, then working up the weight to the desired value using a two-speed electric trickler.  Essentially the powder dispensing and measuring portion shown in this video.

From what I gather reading the various documentation from the vendor, the scale can send out status & data and receive some basic commands via this serial port.  The trickler, being electric with two push buttons for slow or fast speed shouldn't be too hard to control via a couple relays or something similar.  Ultimately I'd like to have a setup where I can input a target value, push or click a button, and have it auto-magically dispense and trickle the charge to the desired weight (plus or minus a reasonable tolerance).

I've been tinkering with Python and PyQt a bit recently, and I get the impression that using the pyserial module I *should* be able to get the readout from the scale directly if desired.  I will probably test first with HyperTerminal or something to make sure I'm 'seeing' the data first, then work on getting an interface going between Python and an application dialog.  I think I have a serial-to-usb adapter around here somewhere; if not I can get one easily enough.

If I get the data directly from the scale to the computer, then I'd have to 'only' use the Arduino to control the trickler... and work out the code (in Python) to take the value from the scale and send to the Arduino via another serial connection how much to pulse the trickler to hit the target without going over.  I do worry a little about the computer getting bogged down by some other process running unexpectedly - not sure if thats really a valid concern or not though?

If I have the Arduino get the data straight from the scale as well as control the trickler, then the only 'need' for the computer would be to send the desired target setpoint, and to retrieve the final value for display/recording.

Or... if I had some sort of LCD display and numeric keypad set up on the Arduino, would the computer be necessary at all (other than programming or setting special parameters).


Thoughts or suggestions?

TIA,

Monte
8  Using Arduino / Installation & Troubleshooting / Re: getting user in the right groups on: November 25, 2011, 03:27:50 pm
I also asked in the 'Programming/Scripting' forum on opensuse.org... apparently there is an ongoing issue with the permissions on /var/lock for a while now, where /var/lock is assigned to the group 'root', not 'lock'.  It was supposedly fixed for 11.3, but it appears things regressed a bit...

I suppose I'll have to change either the permissions or the group ownership for the time being... just a little hazy about what kind of problems I could be causing by changing the group ownership away from 'root'.  Have you noticed any problems since doing so?

Thanks,

Monte
9  Using Arduino / Installation & Troubleshooting / getting user in the right groups on: November 24, 2011, 11:33:19 pm
Hello all,

Now that I have openSuSE 12.1 running on my laptop, I wanted to get busy with my Arduino (got it a while ago but the summer got busier than expected).

So, I'm looking at the instructions from here:

http://arduino.cc/playground/Linux/OpenSUSE

and here:

http://old-en.opensuse.org/Arduino

The former says to add the user to the groups lock, uucp, and dialout.  The latter discusses changing the permissions on /var/lock and /dev/ttyUSB0 to 777, which seems like a bit of a security hole?

At any rate, I did add my user to the aforementioned groups... but I still get a lot of complaints from the arduino program when I launch it from the console:

Code:
monte@suse:~> arduino
Error parsing gtk-icon-sizes string: ''
LOCKING /dev/ttyS7
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS6
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS5
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS4
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS3
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS2
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS1
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS0
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS7
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS6
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS5
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS4
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS3
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS2
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS1
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
LOCKING /dev/ttyS0
lib_lock_dev_lock() lockstatus fail, are you in group 'lock'?
monte@suse:~>


Now the arduino app *does* launch, but I'm concerned about those error messages - especially since I *am* a member of group 'lock', and I did log out and back in - I even restarted the computer.  The current (default) permissions on /var/lock look to be 755... do I really need to change them to 777, or even 775, to allow my user to be able to write to /var/lock?  Is that necessary for the arduino app to work correctly?

TIA,

Monte
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