Shop OBEX P1 Docs P2 Docs Learn Events
Dynamixel AX12 — Parallax Forums

Dynamixel AX12

PatrickS1981PatrickS1981 Posts: 17
edited 2010-05-14 06:23 in Propeller 1
Hi,

Im starting with robotica and I really loved to start with a propeller board. The thing is, I also want to use dynamixel ax12 servos. I saw 1 picture of an dynamixel connected to a protoboard. Are there factory propeller boards with an integrated connector for dynamixels?

Patrick

Comments

  • kwinnkwinn Posts: 8,697
    edited 2010-05-11 21:35
    I took a quick look at the dynamixel ax12 servo user manual and it should be very simple to use with a propeller even though I am not aware of any prop board with integrated connectors for it. The power, ground, and data lines are all that are required to connect to them, and up to 254 servos can be daisy chained.
  • hover1hover1 Posts: 1,929
    edited 2010-05-11 21:38
    It looks like the use the Molex 3P line of connectors from what I have read very quickly. They are .1" spacing connectors that can be solder directly to Protoboard.

    I believe they deal with a higher voltage on the communications buss, but that's very easy to accomodate.

    Do you have a link to the picture?

    Jim
  • ratronicratronic Posts: 1,451
    edited 2010-05-11 23:03
    @PatrickS1981, I have used the propeller demo board and the propeller professional devolpment board with the dynamixels. There are a couple of different objects in the object exchange for them under motor control. Attached is a video link showing a arm I built using them and the demo board with a mouse.



    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    ···································Fix it, if ain't broke!


    D Rat

    Dave Ratcliff N6YEE
  • Mike GMike G Posts: 2,702
    edited 2010-05-12 02:48
    Here's another type of AX-12/Propeller arm.

    http://www.youtube.com/watch?v=07AI2uXGZ-k
  • PatrickS1981PatrickS1981 Posts: 17
    edited 2010-05-12 07:43
    Thanks for the help!
    After this advice, maybe someone·has an other suggestion, that is better in their opinion.... Ultimately I want to create a humanoid with 16-20 servos and some sensors...

    Post Edited (PatrickS1981) : 5/12/2010 8:04:10 AM GMT
  • kwinnkwinn Posts: 8,697
    edited 2010-05-12 16:18
    The AX-12 looks like a very nice servo and seems to be very simple to control and connect to power and the data line. Hard to imagine finding a simpler hardware setup. Multiple units will require a separate power supply. They can not all be powered through the prop on board regulator.
  • PatrickS1981PatrickS1981 Posts: 17
    edited 2010-05-12 19:27
    hover1 said...
    It looks like the use the Molex 3P line of connectors from what I have read very quickly. They are .1" spacing connectors that can be solder directly to Protoboard.

    I believe they deal with a higher voltage on the communications buss, but that's very easy to accomodate.

    Do you have a link to the picture?

    Jim
    I found this document. http://www.crustcrawler.com/products/smartarm/docs/Connecting_the_Parallax_Propeller_Board_to_the_AX12_Smart_Arm.pdf
    Think im going to stick with it. So create this, add some dynamixels. Give them sepperate power and test it...
    ·
  • hover1hover1 Posts: 1,929
    edited 2010-05-12 19:32
    Nice find Patrick! You are on your way!

    Jim
    PatrickS1981 said...
    hover1 said...
    It looks like the use the Molex 3P line of connectors from what I have read very quickly. They are .1" spacing connectors that can be solder directly to Protoboard.

    I believe they deal with a higher voltage on the communications buss, but that's very easy to accomodate.

    Do you have a link to the picture?

    Jim
    I found this document. http://www.crustcrawler.com/products/smartarm/docs/Connecting_the_Parallax_Propeller_Board_to_the_AX12_Smart_Arm.pdf
    Think im going to stick with it. So create this, add some dynamixels. Give them sepperate power and test it...
  • PatrickS1981PatrickS1981 Posts: 17
    edited 2010-05-12 20:18
    This is probably a stupid question, but im still a big noob [noparse];)[/noparse]
    The breadboard that is on a demo board, is that actual connected to something? Or could I buy for instance the Propeller Robot Control Board or the schmartboard (if im adventures) and connect a breadboard to it?
    And is zigbee fast enough to work with dynamixels? Because they operate at 1mbit and the zigbee much slower.

    Patrick

    Post Edited (PatrickS1981) : 5/12/2010 8:45:05 PM GMT
  • Mike GMike G Posts: 2,702
    edited 2010-05-12 21:45
    PatrickS1981 said...
    The breadboard that is on a demo board, is that actual connected to something?
    The white breadboard is glued to the Propeller Demo Board. It's not connected to anything out-of-the-box.
    PatrickS1981 said...
    Or could I buy for instance the Propeller Robot Control Board or the schmartboard (if im adventures) and connect a breadboard to it?
    Sure
    PatrickS1981 said...
    And is zigbee fast enough to work with dynamixels?
    Yes, the following AX-12 driver will take serial input from 9600 to 115200 and send it along to the AX-12 bus at 1Mpbs. You'll also find a Dynamixel library written in C#.
    http://www.agaverobotics.com/services/dotnet/Dynamixel/default.aspx

    It might take minor tweaking to get the Zigbee device to work FullDuplex.spin but I don't think that will be a problem at all. The throughput is pretty good at 115200 since the AX-12 driver buffers the Instruction/Status packets.

    A word of caution about the document posted. A better design is to use a 1k pull-up and a large 10-100K resistor between signal and ground. When you get into the teens of AX-12s on the bus, this circuit will be more sensitive to the AX-12 Rx signal and it works fine with a few AX-12s too.

    Post Edited (Mike G) : 5/12/2010 9:54:59 PM GMT
  • PatrickS1981PatrickS1981 Posts: 17
    edited 2010-05-12 22:03
    Thanks for the info. It surely helps.. [noparse]:)[/noparse]
    Im still doubting because the dynamixels are really expensive [noparse];)[/noparse] But I really like them.
    But to find a second alternative, if I would buy the Propeller Robot Control Board can I then use 2 normal motors and maximal 24 servos (this could be less if I would use a zigbee module and some sensors) or did I missunderstand. If I would connect 20 servos to it, will it have enough power? Or do I need to do something for extra power? Secondly, can someone point me out a good document how I would connect a zigbee module to the propeller boards..

    I hope you guys dont mind that I ask so much things, but I really need to learn a lot..

    Patrick
  • Mike GMike G Posts: 2,702
    edited 2010-05-13 01:13
    PatrickS1981 said...
    Propeller Robot Control Board can I then use 2 normal motors and maximal 24 servos (this could be less if I would use a zigbee module and some sensors) or did I missunderstand. If I would connect 20 servos to it, will it have enough power?
    You'll need to find an appropriate power source to drive 20 servos and your electronics. It's just a matter of reading the specs and doing some addition.
    PatrickS1981 said...
    Secondly, can someone point me out a good document how I would connect a zigbee module to the propeller boards
    You could start by looking in the object exchange.
    http://obex.parallax.com/objects/146/
  • PatrickS1981PatrickS1981 Posts: 17
    edited 2010-05-13 09:45
    Mike G said...
    PatrickS1981 said...
    Secondly, can someone point me out a good document how I would connect a zigbee module to the propeller boards
    You could start by looking in the object exchange.
    http://obex.parallax.com/objects/146/
    Object exchange is for code isnt it? I was looking for information about how to connect it physical to the propeller robot controller board. I saw that I need a xbee 5V/3.3V adapter board and a zigbee module. Bet then I should connect it somehow to the robot controller board. I search for some time but couldnt find a guide on how to do this..

    I can use the xbee usb adapter board and connect it also with USB to the robot controller board. I thought the usb connection was only for the pc side, but appearantly it also works on the controller side... (or am i incorrect)·Think im done then, I know my board, know how to connect it remotely, can work with dynamixels or normal sensors and add extra sensors.... Whoop, set complete... Just give it an other thought and I can order it.

    Thanks for your help!

    Patrick

    Post Edited (PatrickS1981) : 5/13/2010 11:39:26 AM GMT
  • Mike GMike G Posts: 2,702
    edited 2010-05-13 13:34
    PatrickS1981 said...
    I can use the xbee usb adapter board and connect it also with USB to the robot controller board
    Doubt it. The USB provides power to the xBee module. You'll need to wire the xBee IO pins to the Propeller IO.
  • PatrickS1981PatrickS1981 Posts: 17
    edited 2010-05-13 16:30
    Maybe I should contact parallax about this. This was stated on their website:
    This low cost XBee USB Adapter Board comes in partially assembled kit form and provides a cost-effective solution to interfacing a PC or microcontroller to any XBee or XBee Pro module
  • Mike GMike G Posts: 2,702
    edited 2010-05-14 01:02
    The XBee USB Adapter Board found on the link below allows you to connect your PC to the xBee via USB (FTDI).

    http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/xbee/List/0/SortField/4/ProductID/643/Default.aspx

    You might want to read the manual. It explains in detail how to use the XBee USB Adapter Board.
  • PatrickS1981PatrickS1981 Posts: 17
    edited 2010-05-14 06:23
    Im not sure, maybe I interpreted the text wrong. But I verified it with parallax.. Because im still a newbie, i asked them to check if I understand it correct how I could do it by sending a image. It should be correct like this, so then Im ready to shop [noparse];)[/noparse]
    Schema.png
    1686 x 822 - 144K
Sign In or Register to comment.