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31  Products / Arduino Due / Re: Due External Interrupts on: December 05, 2012, 01:36:33 am
I haven't got a Due board, so Im guessing.

Is the 2.5V well within the specs for a high ?, maybe try 3V

Are the other pins floating, try tying high or low

Have you tried on another board, ie 8 bit, whats the result ?

Also on the output shown, is that without pressing the button at all ? like never pressing the button
32  Using Arduino / Programming Questions / Re: How to fit a variable in a fixed position in ram on: December 05, 2012, 01:35:21 am
Just really my lack of knowledge of C, but its improving heaps

Thanks
33  Using Arduino / Programming Questions / Re: How to fit a variable in a fixed position in ram on: December 05, 2012, 12:29:45 am
Main reason is debugging really, dump 50 bytes etc., but also after speed, tho with the 32bit Due this is probably not going to be much of an issue.
But you are right, I do get flashbacks, lots at times.

Do I have to do it in Assembly or can this be done in C ?
34  Using Arduino / Programming Questions / How to fit a variable in a fixed position in ram on: December 05, 2012, 12:03:15 am
How do I assign variables to a fixed location in ram in C ?

I have a quite a few variables declared as static and what I would like to do is to place these variables in a set order and then later send these via serial in a set order by starting a ram address xx

Or should I just let the compiler take care of this ?

Ta

Kim

35  Using Arduino / Programming Questions / Re: The HATRED for String objects - "To String, or not to String" on: November 22, 2012, 01:49:44 pm
Thanks

Coming from Assembly and a bit of basic, I'm trying to get my head around the GNU C compiler and the way it does things.
Been reading the GNU documentation, but sometimes it is "clear as mud" :-)

K
36  Using Arduino / Programming Questions / Re: The HATRED for String objects - "To String, or not to String" on: November 22, 2012, 03:43:37 am
Interesting and thank for clarifying this.

One question tho

When allocation static memory does that automatically become a global variable ?

Kim
37  Using Arduino / Motors, Mechanics, and Power / Great Motor Tutorial on Youtube on: November 13, 2012, 11:03:53 pm
There is a great tutorial on youtube which explains all the basic operations of the DC Motor.



38  Products / Arduino Due / Re: Building a CAN communication protocol interface for Arduino DUE on: November 13, 2012, 02:05:37 am
I think its important that the Library be made so it can run as a background task in a scheduler.
Also that the auto transmit messaging be selected to be optional as sometimes you don't want it to keep transmitting.

K
39  Products / Arduino Due / Re: Arduino Due Task Scheduler on: November 08, 2012, 11:58:33 pm
Maybe some consideration should be given to a "Time Triggered" OS
Link here to a free book
http://www.tte-systems.com/books/pttes
Also they have quite a few seminars on YouTube.

Their hybrid system is a co-operative scheduler with just one interrupt.
This system gives a lot of predictability (in terms of time) and by allowing just one interrupt, all the issues relating to pre-emptive multi-tasking are virtually bypassed.

Their system is often used in safety related applications, ie car, planes,

Here is a link to a port to Arduino (well a beginning anyway)
http://chrisbarlow.wordpress.com/2012/09/13/reliable-task-scheduling-with-arduino-avr/#comments

Just my 2c

Kim
40  Using Arduino / Motors, Mechanics, and Power / Re: Motor/encoder calculations - Accell, Decell and Stopping Distance on: October 30, 2012, 01:34:18 pm
Well, from what I can gather, I properly need to update speed/count/corrections every 1mS or so.
It seems that generally a PI function is used, instead of a PID, when it comes to motor control.

I'll spend some time trolling through PIC, Freescale, etc website looking for papers.
Some of the specific motor control chips may have some S/W that I can look at.

Thanks for the AccelStepper suggestion. Their site has some good stuff and the forum is usefull :-)
in case someone else is looking, here is the link
http://www.open.com.au/mikem/arduino/AccelStepper/

K
41  Using Arduino / Motors, Mechanics, and Power / Motor/encoder calculations - Accell, Decell and Stopping Distance on: October 30, 2012, 03:23:15 am
Hi

I have a motor with an quadrature encoder attached.
Reading the encoder, I can get the counts okay.

I would like to be able to go to a certain position (count), using a set max speed, a set acell and decell rate, possible a S curve for smooth operation, including some sort sort of correction in case of over/under shoot.
I have searched this site but not found anything.
Google hasn't produced much either. Either some very theoretical paper or nothing complete

Any suggestion appreciated

K
42  Products / Arduino Due / Re: StandardFirmata on Due on: October 29, 2012, 03:00:19 am
Sometimes it is handy to be able to switch i/o's using Firmata.
Like to check connected hardware is working okay.
43  Using Arduino / General Electronics / Re: 12 to 24V input on: September 26, 2012, 04:59:22 am
Okay

here are 2 schematics with one being from a control board we use at work (uses a Freescale chip, not AVR)
I have transfered it over for the Arduino board, but as said it has to be a factor of 5.

So, how come this other one works when there are essentially two 330K resistor in series between VDD and GND, which should give 6 to 12V on the chip pin when the switch is O/C ?

The "IN 0-7" connector goes straight to the chip pin
CN8 connect to the outside world. Input is ON the switched to GND
VDD is 12-24VDC


K
44  Using Arduino / General Electronics / Re: Does this exist: Relays that are neither normally open nor normally closed. on: September 25, 2012, 05:30:11 pm
As the above have pointed out, but sometimes you do need to remember a state after a power disrupts.
Latching relays where often used in the security industry where a key-switch would set or reset the relay and the relay would stay in that position until electrically motivated to change.

K
45  Using Arduino / General Electronics / Re: Open Workbench Logic Sniffer on: September 25, 2012, 05:09:23 pm
Some more info here
http://papilio.cc/index.php?n=Papilio.Papilio

The Papilio crowd is pretty good, bought some FPGA boards from them. All good.
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