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Sudo'S Guide To Dynamixels

PLEASE NOTE: THIS GUIDE IS OUTDATED. BADLY. (remind me later to fix this and spiff it up a bit, please)

So, you finally have your EZ-B v4. You love it already, and you're ready to hook this baby up to some sort of Dynamixel powered creation. You go to plug everything in, and - wait. You have no idea how to set those Dynamixels up.

Well, I do, and I'll show you how.

SECTION 1: GETTING TO KNOW DYNAMIXELS

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Dynamixels are intelligent servos that can track not only position, but temperature, speed, and load. The servo can automagically shut itself of incase of a failure. These servos are also incredibly strong. But there's one feature in particular that is useful, but at the same time a little hard to wrap your head around. In this section, we will cover daisy chaining and other features of the AX-12A Dynamixel; however, most of the servos in the Dynamixel family work exactly alike, so this guide can help you with most models.

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On the back of all of your Dynamixels, you will notice a couple things. A place for a bolt, a light, two wire ports, and the ID. Lets go over all of them so you know what they do:

Light - Blinks once when turning on. If the light is flashing, there is a failure of some sort.

Screw hole - Allows you to attach the Dynamixel to a bracket.

Wire ports - Allows you to connect to other Dynamixels, in a long strand of servos, both to and from other Dynamixels. This means both ports work the same way, which means it doesn't matter which side is plugged in. (see image below)

ID - What the EZ-B and ARC address the Dynamixel as.

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PART 2: CONNECTING YOUR DYNAMIXELS TO THE EZ-B

All Dynamixels must plug into port D5 in order to properly work. This means that all of your Dynamixels must plug into one port. If you have more than one strand of connectable Dynamixels, you will have to use a Dynamixel splitter hub, like this one here:

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You can either run a cable to the EZ-B via a power base or via the powered splitter. I advise that you use only one, as using both at once can brown out the EZ-B.

Q: So, now that that's done, what power supply do I use? Mains or a battery pack?

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A: Both will work just fine. Just make sure you have an adequate power supply at around 10v.

"But wait!" you scream. "Dynamixels can run at 9v-12v! Why 10v?"

Because voltage is gradually lost over time depending on how many servos you're running at once, as well as when the EZ-B is powered on. The more servos you have, the higher you should up your voltage to get a steady 10v overall.

So, if you have power running to the EZ-B, Dynamixels set up to port D5 (as well as the optional splitter) you should have something resembling this:

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Now that you're powered on, lets move into ARC and get your Dynamixels running.

PART 3: OPERATING THE DYNAMIXELS WITH ARC

Connect to your EZ-B as usual (We won't be covering connections in this guide). Bring up a servo control panel and go to the servo configuration screen as shown below.

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Click the Dynamixel box and scroll down until you see the ID of the Dynamixel you want to move (the ID on the back of the servo). In this demonstration, we'll be selecting Dynamixel AX18.

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Select it and save the configuration. Congrats, you just set up your first Dynamixel in ARC! It should operate just like a normal servo. This applies to all servo control functions.

PART 4 (EXTRA): ASSIGNING A NEW ID TO BLANK SERVOS

When you buy a Dynamixel that doesn't come in the kit, the ID sticker will sometimes be blank, which means it hasn't be assigned a "real" ID. However, a tool in ARC can give Dynamixels a new ID.

First, open up the Dynamixel Config. control in ARC. You should see something similar to this:

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All blank servos are assigned ID 1. If you have a dynamixel with the ID 1 already, remove it before you proceed. Simply choose the new ID you want (in this case, AX18) and press execute. ARC will assign it a new ID. That's it, you're done! You can also write the ID on the blank tag if so desired.

GUIDE LAST UPDATED: 12/9/2014


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#121  

@mtiberia Really nice work... Dynamixels are on my list of things to learn.... Thanks for the demo:)

#122  

are you making a dragon bot confused confused

#123  

@mtiberia, Will your scripts read and perform from the Robotis 'RoboPlus Motion' files? If not now, do you plan to make that happen? Including the 'RoboPlus Task' file processing would be a big help. I am still hoping to enhance my Robotis Bioloid robot with some of the EZ B4 capabilities.

#124  

@Oldbotbuilder

Sorry but I don't have DJ' s coding skills.

There is a steep learning curve when learning new programming languages. I just couldn't get my head around figuring out C or C++ and writing classes and defining all the variables and placing the " { " in the right place.

Then I found languages like python and EZ script of course. These are two examples of "script" code, all those details that are so numerous to mention are done for you.

DJ has done this all on his own, which blows me away !

EZ Script combined with the EZ-B really has some amazing potential, it will continue to grow one small feature at a time.

#125  

@mtiberia,

Quote:

EZ Script combined with the EZ-B really has some amazing potential, it will continue to grow one small feature at a time.
.

How true.

I will try to interface my Robotics Bioloid to the EZ-Bv4 using the UART to transmit/receive the 5 word Comm packet; FF 55 Data_l ~Data_l Data_h ~Data_h ~ represents Inverse (1's Complement) like the Robotis boomerang controller sends.

#126  

This is great! Very cool work! Could you post a pic of how this is wired? Smoke is not good for my EZ-B!

United Kingdom
#127  

I was fortunate to get my hands on some AX 12 A Dynamixel servos recently and started to read through this thread to find out how to use them with an EZ-B. Then I see the thread take a bit of a nosedive in regards to issues using the Dynamixels, then it seemed to come back up again.

So I just wanted to ask, what is the deal with Dynamixels servos and the EZ-B now. Can they be used with no issues, or is there still something that I should be aware of?

Thanks guys.

#128  

Using a script from comment #120 you can program movements using the AX-12 servos and then play the movements back. It looks very cool and I will test it out when I get a chance. I want the AX-12 servos to work as easy as regular servos. I have 42 of the AX-12 servos to have fun with!