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1  Products / Arduino Due / Re: Arduino Due free memory on: August 15, 2013, 12:01:51 am
Try that, works for me, it is a starting point.

Code:
#include <malloc.h>
#include <stdlib.h>
#include <stdio.h>

extern char _end;
extern "C" char *sbrk(int i);
char *ramstart=(char *)0x20070000;
char *ramend=(char *)0x20088000;

void setup() {
        char *heapend=sbrk(0);
register char * stack_ptr asm ("sp");
struct mallinfo mi=mallinfo();
printf("\nDynamic ram used: %d\n",mi.uordblks);
printf("Program static ram used %d\n",&_end - ramstart);
printf("Stack ram used %d\n\n",ramend - stack_ptr);
printf("My guess at free mem: %d\n",stack_ptr - heapend + mi.fordblks);
}

void loop() {

}
2  Using Arduino / Motors, Mechanics, and Power / Re: Controlling 2x 24 volts DC, 450 watts motors. Where do i start ? on: September 30, 2012, 01:33:41 pm
I finally chosen the Sabertooth2x25 motors driver http://www.dimensionengineering.com/products/sabertooth2x25
for these options:
25A continuous, 50A peak per channel
6-30V nominal, 33.6V absolute maximum
Input modes: Analog, R/C, simplified serial, packetized serial

Also has an Arduino library for packetized serial and Simplified Serial input modes. http://www.dimensionengineering.com/info/arduino

3  Using Arduino / Motors, Mechanics, and Power / Re: Controlling 2x 24 volts DC, 450 watts motors. Where do i start ? on: September 19, 2012, 10:03:10 am
Hi,
Everything going well about this project. I have one question... For test purpose, is there a problem running my 24 Volts DC 450 watts motors with only one 12 Volts battery ?
4  Using Arduino / Motors, Mechanics, and Power / Re: Controlling 2x 24 volts DC, 450 watts motors. Where do i start ? on: September 09, 2012, 09:16:50 pm
Found this Home Built Dual 50A H-Bridge Circuit http://www.ianjohnston.com/content/index.php?option=com_content&view=article&id=63 wich is quite nice.

- Dual Channel (able to control each output independently).
- ~50A continous per channel @ 24vdc.
- Beefy design in terms of terminals, cooling etc.
- Output stage containing both N-type & P-type Mosfet for push/pull operation.
- PWM controlled with added logic for motor direction control input.
- Logic for protection against turning both left or right side push & pull mosfets on at the same time (a sure recipe for smoke!).

Design Specifications:
DC supply / Motor drive output = 10 - 30vdc.
PWM / Direction control logic = 5vdc TTL.
PWM frequency = Tested at 488Hz (standard Arduino PWM) & 1.95kHz (should also work a lot higher).
Main output max. load (Amps) = T.B.A. (theoretically = 50A).
+5vdc supply (onboard logic & external)= 0.5 Amp max (1.0A if you upgrade the inductor).

IMPORTANT NOTE: This design offers no real over-current or over-temperature protection. You will also need a suitable heatsink.

5  Using Arduino / Motors, Mechanics, and Power / Re: Controlling 2x 24 volts DC, 450 watts motors. Where do i start ? on: September 08, 2012, 04:14:53 pm
Interesting stuff but it need to be Arduino controlled motor drivers.

The below might be worth looking at.

http://www.monsterscooterparts.com/otco.html


6  Using Arduino / Motors, Mechanics, and Power / Re: Controlling 2x 24 volts DC, 450 watts motors. Where do i start ? on: September 08, 2012, 12:44:15 pm
For my amps requirement, i could use 2 VNH5019A to get 24 A (60 A peak) to a single motor connected to both channels but i still have the 24 volts overvoltage protection issue.

Documentation also says that it can survive input voltages up to 41 V.
7  Using Arduino / Motors, Mechanics, and Power / Re: Controlling 2x 24 volts DC, 450 watts motors. Where do i start ? on: September 07, 2012, 01:10:18 pm
The VNH5019A-E itself cost $9.20 qty 1, from Digikey
Looks good. Heat sink will be needed
I'll buy one full board from polulu for testing.
8  Using Arduino / Motors, Mechanics, and Power / Re: Controlling 2x 24 volts DC, 450 watts motors. Where do i start ? on: September 07, 2012, 12:45:52 pm
No, i do not have lots of knowledge and experience but i'm ok with programming Arduino. I have to get 50+ units, would it be smart to go DIY and be guided ?
9  Using Arduino / Motors, Mechanics, and Power / Controlling 2x 24 volts DC, 450 watts motors. Where do i start ? on: September 07, 2012, 12:26:12 pm
I did search about it already and do i really need this stuff ?
http://www.robotshop.com/world/pololu-dual-motor-driver-shield-arduino-3.html
Pretty much expensive, any alternative ?

Thanks
10  Using Arduino / Networking, Protocols, and Devices / Re: Mighty 1284p SPI / Ethernet how to get it work ? on: August 08, 2012, 09:49:32 am
I just got back from summer hollidays, sorry for not giving back any infos soon after Nick sent his message about a fix. I did not had time to tried.
Really, only DHCP does that ? i tried both fixed IP and DHCP and the result was the same. IIRC last month test.

I found that the issue only exists when attempting to use DHCP.
11  Using Arduino / Networking, Protocols, and Devices / Re: Mighty 1284p SPI / Ethernet how to get it work ? on: July 01, 2012, 08:22:34 pm
Well i did change the lines inside w5100.h but it still doing the same.
Feels like i don't know what i'm doing. :-)

12  Using Arduino / Networking, Protocols, and Devices / Re: Mighty 1284p SPI / Ethernet how to get it work ? on: July 01, 2012, 04:31:47 pm
Nothing else we can do ?  smiley-roll
13  Using Arduino / Networking, Protocols, and Devices / Re: Mighty 1284p SPI / Ethernet how to get it work ? on: July 01, 2012, 01:26:29 am
All sketch from the Ethernet examples. Basic stuff.
Arduino 1.0, 1.0.1 on either Windows7 or Mac OS X latest

I'm very confused at this point, i  manage to find solution all by myself most of the time, must be a silly thing hanging there.
14  Using Arduino / Networking, Protocols, and Devices / Re: Mighty 1284p SPI / Ethernet how to get it work ? on: July 01, 2012, 12:58:03 am
Actually, i was referring to D4, D5, D6, D7  smiley-red

Anyone here has Ethernet working on Mighty 1284p ?
15  Using Arduino / Networking, Protocols, and Devices / Re: Mighty 1284p SPI / Ethernet how to get it work ? on: June 30, 2012, 11:41:57 pm
Nick,
Pretty much straightforward set-up. It works with any atmega i have here but not the 1284p, go figure. I've tried all week.

I use an Ethernet Shield (no SD) and i power it with 3.3 v, connect the ground of course. Then, i wire pins 10, 11, 12 and 13 to the 1284p 4, 5, 6, 7  like this 10->4, 11->5, 12->6, 13->7
The 1284p operates correctly until it hit line Ethernet.begin(mac)
It freeze right there.

Like i said, i do the same thing for months with other megas and it is all fine.
FYI, i've also tried Jeelabs Ethercard, using ethercard library, diferents SS_pin but same problem. Again, works fine with other megas.

Thanks for the help.
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