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1  Using Arduino / Motors, Mechanics, and Power / Re: newbie to servo's on: May 27, 2014, 10:02:23 am
Quote
do servo with feedback exist ?
Yes they are not common and they are very expensive. They tend to communicate through serial commands and can report back there position. I saw one the other week and it cost $220. It was the RX28 from Dynamixel.


or this : http://forums.trossenrobotics.com/tutorials/how-to-diy-128/get-position-feedback-from-a-standard-hobby-servo-3279/

:-)
2  Using Arduino / Motors, Mechanics, and Power / Re: newbie to servo's on: May 27, 2014, 09:57:26 am
do servo with feedback exist ?

Adafruit have this one

indeed, nice, one can even do this on any servo, it's just a wire soldered to the servo's potentiometer :-)
3  Using Arduino / Motors, Mechanics, and Power / Re: newbie to servo's on: May 27, 2014, 09:33:47 am
Basically it can't. You normally leave a delay so that you assume it is in the right position.

do servo with feedback exist ?

the servo/arduino main page says the library can deal with many different servo motros types,
how do i set these up regarding wich motors i'll buy ???
4  Using Arduino / Motors, Mechanics, and Power / newbie to servo's on: May 27, 2014, 09:25:24 am
hello,

i wanted to use servo motors but i have a few noob questions

- how to chose a servo : i need to make something turn around a pivot as -90°<>0°<>+90° for instance
- how can a simple pwm wire control a servo, does it encode the required degree ? i dont get it
- how does the MCU to assert that the servo is in the requested position ?
- the servo/arduino main page says the library can deal with many different servo motros types,
how do i set these up regarding wich motors i'll buy ???

thx
5  Using Arduino / Programming Questions / Re: Serial differenciation... on: April 10, 2014, 05:42:53 am
...The Arduino has the DTE signal hardwired into the reset circuit....

so what would be usefull is that when i run my C++ code, i engage the reset on the arduino
(and then wait a while that the bootloader finishes)

so what is the chain of states do i need to put the DTE(DTR?) line ?

high, low, high/low, low/high ??

[edit : ok i got his in C++  (i use termios.h for communication)

    /* sets the baud rate to 0 => (hangup) => DTR=LOW => DTE(computer) not present => arduino reset */
    cfsetospeed(&oldtio, B0);
    cfsetispeed(&oldtio, B0);
    tcsetattr(fd,TCSANOW,&oldtio);
    sleep(1);

it is actualy engaging the arduino reset :-) yeay
]
6  Using Arduino / Programming Questions / Re: Serial differenciation... on: April 10, 2014, 05:37:25 am
Quote
well that's an issue..that i was expecting, hence my question
one is supposed to be able to send any kind of data through serial interface
i guess i'll have to use Serial1 instead
You're not paying attention. The "!!!" sequence is ONLY an issue if you have a Mega bootloader AND it's an issue ONLY when the bootloader is receiving the data. The bootloader will NOT be running when your code is running AND you can't upload code on Serial1

ok, that's right sorry about the mistake, indeed it concerns the bootloader...

i was talking about Serial1 for communication, not for code upload :-)
7  Using Arduino / Programming Questions / Re: Serial differenciation... on: April 10, 2014, 03:35:29 am

Two caveats:
1)  The sequence "!!!"  (three exclamation marks without the double quotes and without anything intervening) in the uploaded code means something special to the bootloader, so do NOT have this sequence in your program.


well that's an issue..that i was expecting, hence my question
one is supposed to be able to send any kind of data through serial interface
i guess i'll have to use Serial1 instead

thanks for the infos
8  Using Arduino / Programming Questions / Serial differenciation... on: April 09, 2014, 01:35:19 pm
Hello,

i try to understand how the serial interface(usb) is actualy making a difference between the things i send and receive during my program runtime, and the data that are sent/received during code upload

what if the data i send correspond to some binary sequence that will trigger the code upload functions in the arduino firmware ?

i just dont get it

thx
9  Using Arduino / Programming Questions / Re: adressing data from assembler on: April 08, 2013, 08:06:42 am
Quote
i am optimizing my code with inline assembler

Why?

i need fast refresh, and with c code, the led panel flickers
arduino is not that fast
10  Using Arduino / Programming Questions / Re: adressing data from assembler on: April 08, 2013, 08:05:47 am
The compiler optimizes your code too. What makes you think you can do a better job, Rumpelstiltskin?



i know, but if you dont try.. right?

btw i end up having a code 10 times faster

seeing the code in asm,  also helps you understand things that could be optimized
11  Using Arduino / Programming Questions / Re: adressing data from assembler on: April 08, 2013, 08:04:22 am
Quote
i am optimizing my code with inline assembler

Why?

to have you ask why
12  Using Arduino / Programming Questions / Re: adressing data from assembler on: April 08, 2013, 04:30:55 am
anybody ?
13  Using Arduino / Programming Questions / adressing data from assembler on: April 07, 2013, 05:58:36 am
Hello,

[sorry , i could not post this in "Syntax..." on the forum, donno why...]

i am optimizing my code with inline assembler but i got questions...

ex: i have to acess elements of a 2 dimentional array one by one and refer them as operands that gonna be mapped to registers

Code:
__asm__ __volatile__
(

    "mov r24,%[LEDS]" "\n\t"

 : [LEDS] "+r" (leds[0][0].value) ::
);

how do i adress a whole array instead of having to assign 1 register per operand ?

the problem is that if i use too many operands, the compiler generates a lot of code to load data in registers (before my code)
and a lot of code to load modified registers back to the memory (after my code)

so i thought i could do the adressing myself by storing the adress of an array for instance in the z register
and the parsing memory, read/write the required values, but how to do that ?

also the compiler generates a lot of push before my actual asm code (without any pops ??? wtf?)
does anybody knows why and how to supress this, i lose a lot of cycles for nothing as the whole code runs in the "void loop(){...}" section

ex:

Code:

void loop()
{

     400: 4f 92        push r4
     402: 5f 92        push r5
     404: 6f 92        push r6
     406: 7f 92        push r7
     408: 8f 92        push r8
     40a: 9f 92        push r9
     40c: af 92        push r10
     40e: bf 92        push r11
     410: cf 92        push r12
     412: df 92        push r13
     414: ef 92        push r14
     416: ff 92        push r15
     418: 0f 93        push r16
     41a: 1f 93        push r17
     41c: df 93        push r29
     41e: cf 93        push r28
     420: 0f 92        push r0
     422: cd b7        in r28, 0x3d ; 61
     424: de b7        in r29, 0x3e ; 62
     426: c0 90 04 04 lds r12, 0x0404
     42a: 8c 2c        mov r8, r12
     42c: 99 24        eor r9, r9
     42e: 70 91 05 04 lds r23, 0x0405
     432: 87 2f        mov r24, r23
     434: 90 e0        ldi r25, 0x00 ; 0
     436: f0 90 36 01 lds r15, 0x0136
     43a: 2c 01        movw r4, r24
     43c: 44 0c        add r4, r4
     43e: 55 1c        adc r5, r5
     440: 44 0c        add r4, r4
     442: 55 1c        adc r5, r5
     444: 48 0e        add r4, r24
     446: 59 1e        adc r5, r25
     448: 88 e7        ldi r24, 0x78 ; 120
     44a: 90 e0        ldi r25, 0x00 ; 0
     44c: 9c 01        movw r18, r24
     44e: 82 9e        mul r8, r18
     450: c0 01        movw r24, r0
     452: 83 9e        mul r8, r19
     454: 90 0d        add r25, r0
     456: 92 9e        mul r9, r18
     458: 90 0d        add r25, r0
     45a: 11 24        eor r1, r1
     45c: 48 0e        add r4, r24
     45e: 59 1e        adc r5, r25
     460: f2 01        movw r30, r4
     462: ec 5c        subi r30, 0xCC ; 204
     464: fe 4f        sbci r31, 0xFE ; 254
     466: 43 81        ldd r20, Z+3 ; 0x03
     468: 54 81        ldd r21, Z+4 ; 0x04
     46a: 91 81        ldd r25, Z+1 ; 0x01
     46c: 30 91 06 04 lds r19, 0x0406
     470: 3a 01        movw r6, r20
     472: b9 2e        mov r11, r25
     474: a3 2e        mov r10, r19
     476: 27 2f        mov r18, r23
     478: 26 95        lsr r18
     47a: 26 95        lsr r18
     47c: 26 95        lsr r18

}


plz help

thx

14  Using Arduino / Sensors / Re: Need help with connecting 9DOF (ITG3205 ADXL345 HMC5883L) module! on: February 14, 2013, 02:31:24 pm
Hello, i bought that same module
can you put your code on the forum?
i dont understand how to adress the chip from the links given on this page
do you have any datasheet ?
thx
15  Using Arduino / Project Guidance / Re: Arduino ADK compatibility? on: January 30, 2013, 06:38:14 am
nobody ?

is there any ADK specialist who can tell me if it is gonna work ?

i found this android 4 motherboard http://dx.com/p/diy-android-4-0-motherboard-development-board-green-180172

so the simpler question would be
as it is android 4.0 and usb host 2.0
is the ADK arduino board compatible with this ?

thx
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