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1  Using Arduino / Motors, Mechanics, and Power / Re: Max amp load on LiPo battery on: April 04, 2013, 02:17:11 pm
Hey Lefty,

I will definitely check the voltage as you mentioned when I get home, but in theory that battery should be able to handle those high-voltage servos no problem right???

You don't usually have to worry about wire gauge when dealing with amperage below 15 right??

-Alonso
2  Using Arduino / Motors, Mechanics, and Power / Re: Max amp load on LiPo battery on: April 04, 2013, 01:22:26 pm
Hi Retrolefty,

I have an adjustable power supply which I'm setting to 7.4v, and the LiPo battery also shows 7.4v when tested with the multimeter. The batteries are brand new so there shouldn't be any problems with the discharge rate being lower than original.

I'm using three of these high voltage servos:

 http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=18399
3  Using Arduino / Motors, Mechanics, and Power / Max amp load on LiPo battery on: April 04, 2013, 12:56:38 pm
Hey everyone!

I'm running into an issue where I have some servos hooked up to an Arduino, but they aren't drawing enough amps from the LiPo battery. I can hear and see them act much faster when I hook it up to my desktop power supply. The reading on the desktop power supply is telling me it's consuming around 5Amps, but when I use my Lipo battery and try to test it with my multimeter, the max amperage is 1.25 (also it feels like testing amperage with the multimeter is making my servos noticeably slower, do I have a shitty multimeter that is introducing more resistance than normal??) 

I'm using a 7.4v 1800mah 25C LiPo battery which from what I read on the internet, it should have a max amp draw of 45?

Capacity * Discharge rate / 1000 = Max amp draw
1800 * 25 / 1000 = 45 amps

I'm powering my motors separately than the Arduino so that shouldn't be a problem. I tried switching to a battery with a higher discharge rate of 65C and everything seemed to work fine, but I'm wondering why the other battery can't output as I expected...

Thanks for the help!

-Alonso
4  Using Arduino / Motors, Mechanics, and Power / Re: Dynamixel Servo Library on: November 19, 2012, 01:22:27 pm
Hey druckgott,

The current release of the library doesn't work with MX-28, however he does have a new version that works that he hasn't released.

I would email Pablo Gindel and ask him if he could send you a newer version.

When I find time, I will translate the code into english and make a video tutorial so the learning curve for manipulating Dynamixels with Arduino is  less steep.

Goodluck!

-Alonso
5  Using Arduino / Motors, Mechanics, and Power / Re: Dynamixel Servo Library on: November 16, 2012, 12:40:45 pm
Hello BeepBoop,

The Arduino Uno only has one serial output (Tx and Rx) and I believe that this library needs to have at least two.

I would read all of the comments in Pablo Gindel's website and look for comments using Arduinos with one serial port.  I remember seeing plenty.

What Dynamixel are you using? if you are using the MX-28 then you need a library that Pablo hasn't released yet that I can pass along.

-Alonso
6  Using Arduino / Motors, Mechanics, and Power / Re: Dynamixel Servo Library on: September 23, 2012, 03:56:23 pm
I also tried the following things:

changing my baud rate to 57600 since I read that it's the default for a brand new the MX-28.

AX12::init (57600);

Instead of using Pablo's autoDetect function, hard coding the servo ID to 1, but no luck smiley-cry

motor.id = 1;

Thanks!

-Alonso
7  Using Arduino / Motors, Mechanics, and Power / Re: Dynamixel Servo Library on: September 23, 2012, 03:41:27 am
Hi Flex,

I am also trying to connect a MX-28T servo to an Arduino, but have had no luck. I followed the instructions carefully about changing the "Arduino.h" includes and commenting out the lines in the HardwareSerial.cpp, but I think my wiring is the problem.

When I load the program into my Arduino Mega 1280 using the Arduino 1.0.1 IDE, my serial monitor says the following:
 deteccion: 0
 ID detectado: 1
 delay: 0
 error lectura: 1920
 
posicion: 0
 velocidad: 0
 carga: 0

This is the same output as if I were to run the sketch with absolutely nothing connected. Here is how my wiring is set-up:

I chained 5 batteries in series to raise the voltage up to 12.71 since the recommended voltage of the MX-28 is 10-14.8 volts and the Arduino could only supply 9v.

The Arduino is being powered by the USB.

Ground is connected between the Arduino ground pin, the battery's ground, and the servo ground pin. I heard the ground between the Arduino needs to be connected the ground of the servo's.

The Tx1 and Rx1 are connected in the same row of the breadboard as the data pin for the servo.

Any help would be very useful!

Thanks!

-Alonso Martinez
 
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