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Dynamixels And Herkulex.Again

Love digging up a horse and beating it again? Well fellas I'm here to help you out!

Lets start another up to date discussion about the use of, and the support of, Dynamixels and the HerkuleX line of professional servos. I'm moving up a level with some upcoming projects and steering away from the hobby style servos. I've spent days researching, using geared stepper motors, geared DC motors as servos and have come back full circle to serial servos. Due in part, by all the unknowns and unreliability associated with creating a servo from scratch.

Tell me about your success and failures of using the Dynamixel and HerkuleX servos with EZB. Please be detailed in your experience and add something to what is already written in the prior threads about subject. What needs to change/improve for better support? Perhaps this is adding to existing plugins or writing new ones? Speaking of plug ins (this is probably another topic), but i wonder if there would be more incentive to create plug ins if there was a pay for development? Like how the app store works? Just a thought there.

I really believe in everything EZ robot and want to continue using the products, because well its so EZ and the results are amazing. I'm well aware the majority of sales is in the education market for EZ Robot and therefore guides their company. But, how can we work together as a group to build support for the next level of servos and professional robotics? And ask ourselves what is the motivation to do so?


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#1  
Install the dynamixel plugin and the dynamixel servos will simply just work. Easy as that.

You bet ezrobot is focused on education, and has been since day 1. Are you saying that you've learned nothing using the platform?:P
#2  
Let's see if I remember everything wrong with dynamical plug in as I'm the one who pushed pretty hard for it to work.

So my design includes mx 64 servos , 2 for the elbow joints. These run of of Ttl logic.

Then I was using the classic ax12a servos for elbow rotation and wrist rotation. These should be able to run off of the same buss. In all the robotis videos I have seen there are all different size dynamixels including the ax12a daisy chained together and working. However....

That did not work. And still does not. I then upgraded the ax12a servos to the mx 28t to be daisy chainable. That seems to work but the resolution of these servos is much greater than standard servos so the positioning is way off. I will dig back thru my notes to see what else is not working correctly.

I can say with 100 percent certainty after spending 2,000 on dynamixels that there are still a lot of issues when trying to be controlled with ezb. I have a bunch of ax12a servos laying around now.

Edit: digging back a little the ax12a has a different bit resolution (8) bit? 1024 count while the mx series servos have (12)bit 4096 resolution. There was no way to control the 2 different types having the different resolutions. I could control one servo or the other. As I dig more I'll post more. This issue as well as a couple of personal issues has caused this project to stall.
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#3  
The way to control two different types of dynamixel servos would be the same as you'd have to do with arduino or any other platform, write some code. The native support for dynamixel servos in the ezrobot plugin does not include mixing models/versions.

The resolution can be fine tuned as well in the plugin. As mentioned in numerous threads and your thread, the plugin can always be modified to change the maximum servo position globally of the entire ARC project.
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USA
#4  
@Dj,

You bet I've learned alot!

So with the plug in I should not have any issues with any of the dynamixels (as long as I don't mix versions unless i code)? Thats great news. My project will use the $500 a piece Dynamixel MX-106 servos. There are two flavors, the rs-485 ver and the ttl ver, I'm assuming the ttl ver will be the one I need?!

@kamaroman68, so you are saying that you are unable to get the fine resolution (12bit) with the EZB? I assume it defaults to the 2 degree per step in ARC? Have you tried getting this controller and have the EZB control it?

http://www.trossenrobotics.com/p/arbotix-robot-controller.aspx

I like the HerkuleX but its a lot of plastic (horns, gears etc), the Dynamixels have an all aluminum choice. My project will have to be continuous duty for 52 weeks out of the year, and these servos offer warranty as well.
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Synthiam
#5  
What do you mean by "2 degrees per step in ARC"?
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USA
#6  
Sorry max pulse width of 2 MS or 180 degrees max. Some of dynamixels travel 360 degrees and the HerkuleX have 720 degrees at 12960 steps of resolution.
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Synthiam
#7  
Dynamixel doesn't use the same protocol as a pwm servo. So the degrees isn't related to the pwm (pulse width). What you configure the plugin to scale for degrees will make the actual values different.
#8  
I guess all I am saying is ... although watching trossen videos of mx64t and mx 28t and ax12a all being controlled on the same buss I was unable to do so. So I upgraded ax12a servos to the mx28t servos so they shared common resolution (12) bit 4096 counts. I guess I was misled by the trossen videos. As to coding plug ins Im not there yet.
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USA
#9  
Ok well I've placed an order for both servos and control boards. I'll report back on my results when I get them running in virtual servo mode. Hopefully I can get these working.
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USA
#10  
@kamaroman68

Quote:


although watching trossen videos of mx64t and mx 28t and ax12a all being controlled on the same buss I was unable to do so.


the arm:

http://www.trossenrobotics.com/widowxrobotarm

has mx64t, mx28t, ax12a all in the same bus.

If i read correctly after the upgrade you have a mix of mx28t and mx64t ?

How many servos ? did you get success with ARC ?
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#11  
Can anyone tell me the advantages/differences in rs-485 and ttl? There is a break out board for converting your existing ArbotiX Robocontroller TTL serial port into an RS-485 serial protocol.
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Synthiam
#12  
I have a brilliant idea for the dynamixel plugin that will make you happy! Stay tuned


Here I thought I'd have relaxing evening at home... nerd life!:D
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#13  
Hahaha! A spark of inginuity! Looking forward to it!
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Synthiam
#14  
Here you go: https://synthiam.com/redirect/legacy?table=plugin&id=39

@kamaroman68 will like this update.

Each servo can be configured individually per protocol version and per max position. Also, the global ARC servo resolution can be altered to provide an increase of resolution in all native ARC controls.

This means you can set the global max value from 180 to 360 to provide double the resolution. You may also set it to 720 for 4 times the resolution, etc...
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USA
#15  
Holy smokes! Brilliant!

Now I just have to wait for the servos to arrive :/

Thanks so much DJ for your continued commitment. Once again EZB has raised the bar.. it's all in the code! And that was crazy fast!

I'll let you know how I get along.
#16  
PTP , after the upgrade from the ax12a to the mx 28 t servo I can get all of the mx28 t and mx 64 t servos working correctly on the same buss. Both the mx 64 an the mx 28 have same resolution 4096 counts (12) bit. Unfortunately I had to spend a lot of money to make it work. In the end I have stronger servos.

Another thing about these servos and ezb is that I'll never realize full potential of them. Meaning for example, position feedback, temperature... etc etc. This is not a knock down of ez robot or the ezb, after my beginning issues with ezb I have come to like it quite a lot. I tend to be an over thinker which sometimes hinders more than helps. I just don't know enough about this type of coding to make plug ins. I am a factory controls engineer working with Allen Bradley plcs and Hmi"s. Much different.
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Synthiam
#17  
@kamaroman68 please read my previous post
#18  
Dj Sures I have no reason to update the plug in I have. After spending the money to fix the issue and getting it to work I'd rather not mess with it and have to come up with another work around when it doesn't work.
Again I am no longer using the ax 12a servos so no need. Thanks
PRO
USA
#19  
@DJ, I downloaded the plug and looking around at the controls. I pressed the "?" for global max servo positions and the *note is cut off...but i think i get the gist. If you choose 720 thats going to make for a loooonnnggg drop down to choose positions. Just double checking that was the complete note.

As for protocol 1 and 2, does this relate to ttl and Rs-485 protocols?
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Synthiam
#20  
The protocol relates to the dynamixel servo. I'm not certain about what models use what protocols.
PRO
USA
#21  
OK I'll poke around when the servo arrive! Thanks.
PRO
USA
#22  
@Dj,

Dynamixels come in two versions the TTL version (3 wire) and the RS-485 Ver (4 wire). On the plug in description you have "Each Dynamixel servo contains a microprocessor. The microprocessor is told what position to move the servo into over a RS485 protocol."

I just want to be clear on my understanding.
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Synthiam
#23  
I don't know very much about those servos. So far you know more than me.
PRO
USA
#24  
What type of dynamixel do you have to test the plug with with? the Ax-12?
#25  
Will I don't understand your question but I can answer it when you clarify
PRO
USA
#27  
Well i cancelled my order so i could be sure. I ordered the Rs-485 ver, but i am now ordering the ttl ver of the Mx-28T to test with.
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USA
#28  
With final version being the MX -106T
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USA
#30  
OK great reordering now. Did you have a chance to try the new plug in?
#31  
The ttl version is supposedly easier to make work (3) wire compared to (4)wire rs485. I'm not even sure the ezb 4 can use serial 485 without some kind of converter. Not sure how much your looking to do with these servos but as I said before you will not realize there full potential due to lack of bidirectional communication with the ezb4.
#32  
I did not try the new plug in. In all honesty it took several iterations of dynamixel plug in refinement by DJ to get part of it working for me a while back. I'm almost afraid to go through that again.
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Synthiam
#33  
The physical wiring may be different per version. The easiest is ttl because it can be connected direct. The servos I have used are one per protocol. The ax12 (protocol 1 ttl) and the plastic terrible servos shipped with the Darwin mini (protocol 2 ttl)
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#34  
OK thanks Kamaroman68. The feed back and other things are not important to this project, just a good smooth moving heavy duty servo with a warranty.

@Dj, ok sounds good, I'll see what we can get going with this now i got the right one ordered! Thanks!
#35  
So against my better judgement I downloaded the latest dynamixel plug in. Now none of my dynamixel servos work. Here we go again!
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Synthiam
#36  
Did you configure the new plugin? Every control that is configurable has a gear icon. Press the gear icon to configure the plugin.
#37  
the mx64t dynamixels communicate. I can turn there leds on and off. I can move the mx64t dynamixel servos.

However I can not move the mx 28t dynamixel servos. I can not make the leds turn on and off on the mx28t servos.

My dynamixel bus is left arm mx28t - mx64t - mx28t
right arm mx28t - mx64t - mx28t

Again I can not communicate with the mx28t servos at all.
Thanks
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Synthiam
#38  
Did you configure the correct protocol for the ID's of the MX28t servos? You can configure the protocol for the respective ID by pressing the CONFIG gear icon on the plugin.
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USA
#39  
Let me know how it goes I just ordered the 28-t yesterday.
#40  
mx 28t and mx64t use same protocol and steps/resolution. (4096) protocol 1

Addressed all servos using the utility in ARC.

CAN NOT communicate with the mx28t dynamixel servos.
#41  
Also mx64t servo does not move 0 to 180 degrees when being told to do so. Goes 90 degrees, even if I up the sleep command.

:elbow

Servo(v5,0)

sleep(1000)
servo(v5,180)

sleep(1000)









goto (elbow)
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Synthiam
#42  
The ID's of the servos correspond with the Vxx number of the servo. Select the ENABLE checkbox on the ID's that you wish to enable Dynamixel on. Also select the protocol for each ID. You can do so by pressing the GEAR icon on the dynamixel plugin control.
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Synthiam
#43  
To adjust the resolution, change the resolution per servo in the config menu. The config menu can be accessed by pressing the GEAR icon in the dynamixel control. Each servo has its own position. The position is labelled "Max Position", next to the version dropdown selection per servo.
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#44  
Also, what ID's do you have associated with each servo?
#45  
ID's 1 - 6

I changed max position like you said... when I put 4096 in the servo does nothing.

When I put 1024 in it goes 90 degrees.

When I put 2048 in it goes 90 degrees.

Currently working with v5 which is a mx64t dynamixel servo. Sorry but it does not work. Shoot Id let you remote into my computer if you wanted to.


Too make things simpler for my small mind lately, I have simply put one servo on the line mx64t nothing else addressed v5. I can communicate with it but cannot get it to travel over 90 degrees.


Interesting find... when I put 4095 in the servo works again but still 90 degrees only. Thanks again
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#46  
That was going to be my suggestion. Just one servo on the line to test. I should have mine before the end of this week.
#47  
good luck Will! I hope you have better luck!

Chris
#48  
What I did when I wanted to use Dynamixel (be sure to order the metal geared ones) servos was to purchase the Arbotix controller board and talk to the EZB4 via RS232.
#49  
69 developer,

It may come to that. Please expand on how that works. Do you have program predefined movements in the arbotix controller and then "call" them from ARC? For example sounds simple but apparently not....

"Robot take this"
Gripper opening as the shoulder joint rotates upward. Elbow begins to bend out, wrist rotates into position, gripper closes on object and stops. Do all of these movements need a predefined code? Thanks

Chris

BTW id much rather script all of that in ARC. How hard was the learning curve for the arbotix. For some reason I am picturing arduino type coding.
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#50  
@69developer, that's exactly what I had suggested earlier in this thread. Let me know if you proceed down this road. Just want to cover my bases. As this is a very important project.
#51  
Will do you know how to program that board? ( arbotix-m)?
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#52  
I'm reading on it now. Several programs to use. It uses ardurino environment to code. There are also a couple of UI for creating poses and storing them in flash using python. Seems to be several other programs written as well. Should be able use serial to communicate from EZB to the board.
You have to get a piggy back board to go onto ArbotiX to use any of the dynamixels other than the 12
But still going to try the plug in and work through that first.
#53  
If you need anything, you can find me on Twitter.
#54  
Please keep me up on your progress. I need to use these dynamixels now I cant turn back. Thanks again!
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USA
#55  
Thanks 69developer!

@kamaroman68, I'll post my progress here.
#56  
I remembered today that there is a good resource to learn more about the Dynamixel, which is a great servo, especially when you get into the model 24 and above.


Dynamixel Information
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Synthiam
#57  
Also, as per the Dynamixel plugin description, ensure you have sufficient voltage for operation as per the manual of the Dynamixel servo Model.

Most Dynamixel servo documentation states the operating voltage is between 9-12 volts, with optimal being 11 volts. Check the documentation for your dynamixel servo model to ensure your power source is sufficient. If you experience unusual behavior of Dynamixel servos, the first common issue is insufficient power. Symptoms will be flashing error LED's on the servos or non-operation.

Dynamixel plugin can be found here: https://synthiam.com/redirect/legacy?table=plugin&id=39
#58  
The problem is not the power source. I am using a sealed car battery in my project. The plug in DOES NOT work for these MX series dynamixel servos. Again I offer remoting into my computer so you can see what's going on.
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Synthiam
#59  
The protocol has not changed. I will send you the previous plugin version for comparison.
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Synthiam
#60  
Oh, I should add as well - if you can disable response packets on the servos. It's in the utility section. This is because there could be collision of response packets while transmit packets are being sent.
#61  
I'm really not trying to be a pain. No matter what I put in the resolution the servo moves 90 degrees. I will fool around with this again in the morning. I welcome you to look at this first hand, shoot I'll even send you a copy of my project.
#62  
At this point I just really need these servos to work. I changed the design when the ax12a did not work due to different resolutions. I can not change designs again
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Synthiam
#63  
My responses in this thread are to assure you that I am continuing to look into the situation you are experiencing.

If ezrobot did not wish to work toward a resolution, I would let you know - even for support of this third party product.

Please be patient until a resolution is achieved. It'll happen and get you up and running.
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USA
#64  
I appreciate your continued effort DJ. I know even tho these are 3rd party products you are doing your best with support them. Hopefully we can all work together to trouble shoot them if there is an issue.
Again we know you are super busy and much appreciation for your time.
#66  
Sorry DJ still only giving 90 degrees of travel, this is the simple code doing the movement.


:elbow

Servo(v5,0)

sleep(3000)
servo(v5,180)

sleep(3000)


goto (elbow)

And for troubleshooting purposes only 1 servo on the line. V5
#67  
In fooling around if I put in 1024 in max position I get about 45 degrees of movement. If that helps

And 4096 or 2048 in the max position equals the same 90 degree movement.
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USA
#68  
@kamaroman68, with the 90 degree motion you do get do you feel the motion is smoother than what you were getting with last version of the plug?
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Synthiam
#69  
Where are you entering the value "1024" or "4096" or "2048" Please confirm is it from this image labelled A or B...


User-inserted image
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Synthiam
#70  
I added an update to the latest plugin which displays the version number in the log so that you can ensure it's the latest plugin loaded.
#71  
" B" sorry for the delay, will fire up my machine and see what happens

Chris
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Synthiam
#72  
Are you certain there is no degree limit or setting configured on those servos using a different software package?

I verified the values are being sent - all the way to 4096 and. When I set Servo(v5, 180) and the Max Position is 4096, i can visually see 4096 being sent to the servo via the protocol.

Please check if there is a "reset to defaults" or "factory reset" or some option that you can set for those servos.

I even ran a test for 4 hours straight with the servos running in a loop back and forth with no issues.
#73  
Hmm, Still only 90 degrees of movement, yes updated to version 12.

In all honesty I took the servos out of the box and used ARC utilities to address the servo ID. I don't know of any other software reset with these servos. I will see if I can google anything about resetting these types of servos. Thanks again!

Chris
#74  
So in further troubleshooting I removed the mx64t servo addressed as v5.

I reinstalled the other mx64t servo addressed as v2. To clarify I physically connected the second servo to the buss and took the v5 servo off the buss.
I will now say that the second servo is working. But when I put 180 in the servo actually goes a full 360.

I need to look into finding software to reset a servo or something, as mentioned by DJ in an above post. Im glad to see some of this being resolved. Thanks very much. I will let you know my further progress.

Chris
PRO
Synthiam
#75  
360 is most likely correct if that is the full resolution of the servo. For example, it may be 4096 steps of 360 degree rotation. The AX-12 servos i believe are 300 degrees at 1024 steps.

So 180 may be 360 degrees on a third party servo-motor.

However, i'm not sure what else i can do at this point for trouble shooting. I believe your results, however i'm unsure what could be causing them as i see the correct values being transmitted to the servo during testing.

In my tests...
If Max Position = 1024, then 180 = 1024.
If Max Position = 4096, then 180 = 4096.

See if there is a factory reset or something that could be causing the limited range.
#76  
Yup , Im starting to believe there is either something wrong with the servo or maybe there is another piece of software to modify these things. Thanks again for all your help.

Chris
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Synthiam
#77  
I'll google and see what there could be. I don't see a "factory reset" option in the command protocol list.
PRO
USA
#79  
I get my dynamixel on tuesday. I'll let you know what I get straight out of the box.

All good progress so far.
#80  
DJ yes I just saw that. It also appears I need to use some kind of adapter called a usb2dynamixel adapter in order to talk to that servo. I don't have the adapter I will have to order one. These servos are a PITA! Gosh I hope there worth it.

Just found the software as well. Downloaded it. Of course it needs to be connected to a servo to step thru the setup steps. Anyways thanks again, it looks like this has been cleared up on the ez robot side of things. I will update as I get more working and when I get an adapter.

Chris



Will you should be able to use EZ robot directly without the arbotix controller. I have confirmed it with one of my servos. Now Im sure for whatever reason the other servos fault are my own. Will keep everyone updated.
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Synthiam
#81  
I'll see how much work it is to add a button that resets all the settings on a servo. They don't seem to have a "reset all" or "factory reset" option. But if i can send a string of commands that resets each value to the documented default, that should help.

Stay tuned
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USA
#82  
Yeah that would be a great help DJ. I thought about getting that USB to dynamixel adapter but didn't.. wish I had now just in case for programming them.
PRO
Synthiam
#83  
You should get one. Because these servos are super finicky
#84  
So quick update...

Found out why I could not communicate with my mx28t servos. Factory default baud rate for these servos are 57,600.

MX64t factory default baud rate is 1000000.

Now I guess I need the usb2dynamixel adapter to change the baud rate of my 4 mx28t servos. What a pita.
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Synthiam
#85  
i will add a baud rate change option in the plugin for you today
#86  
DJ first off Thank you very very much. You truly do kick axx!
You have no idea the past 6 months I have had, no idea! I have made so much progress in the last 2 days. It has really lightened the mood, and actually put a smile on my face. Im hoping the new year changes for the better. Thanks again for all you do!
PRO
Synthiam
#87  
Thanks man:D Those are really nice words to hear!

I'm working on the plugin to change baud rate now. Shouldn't take much longer
PRO
USA
#88  
Well now I'm so excited to get the dynamixel! As always, thanks so much DJ. Looks like xmas came early this year!

Edit: I won't even be able to tell anyone about this project for a year :/ but happy I get to stay with the EZB for testing!
#89  
DJ keep going on the plug in for others. Im a forgetful ding bat. I already own a usb2dynamixel adapter, I went and picked it up. Everything is working very well. Again I appreciate all your hard work on this. Ive got to get a picture of my machine up. It is becoming more and more incredible by the day now. Thanks again!

Will the mx28t servos come default 57,600 keep that number in mind. It comes in very handy and with DJ's update you will be able to change it to whatever suits you.
PRO
USA
#91  
Well after playing for an hour, I can say I am over the moon with their performance. Took me a while to see what was happening with the scaling in the plug in, but it works great for what i need. These dynamixels are so quiet and when set to microstepping resolution move so fluid. Thanks again DJ for tackling this beast. Great job!
#92  
Wow, I was just thinking about this a few minutes ago and if you had gotten your new servos. This is outstanding news. I'm really happy for you and relieved you have found a solution. Please keep us posted.
PRO
USA
#93  
Absolutely I will. Setting up virtual servos is the way to go as well. I can control these (as i guess you could with your gear motors) and control them in any of the controls. I set up a simple horizontal servo slider with V1 and used the script recorder to record the motions, then set it up another script to just loop. Works like a regular servo and super powerful at 12 volts.

Of course the price is not for the faint of heart, but you get a one year warranty with your purchase!
#94  
Glad you got them working. These servos are very powerful. I broke a weld during " left arm extend , rotate elbow, home left arm" completely my fault as the programming wasnt quite right. Now I've got it extending/retracting/homing with zero issues.
#95  
Outstanding Will. Again I'm glad you're happy with your servo choice and things are working for you. I know you have a lot riding on this build.

I'll be starting to figure out using the virtual servo feature with my DC gear motors today. I hope I have the success you have worked for. Alan (thetechguru) was kind enough or work up a Example Project about using Virtual Servos with motors and posted it in my project thread. Did you use that Example Project for working through your scripting with the virtual servos?
PRO
USA
#96  
No Dave I didn't see that example file. I just did my best guess and it worked first time. But I see a lot of possibilities using linear actuators D.C. Motors etc with the virtual servos. If I remember correctly you can use the SSC-32 and set those 32 servos as virtual servos taking the load off the EZB. As always seems like the sky is the limit.
#97  
I know your a busy guy but would you mind sharing your virtual servo scripts when you have a chance? I really like to get all the info i can to work through a process. Looks like have yours working and I could really use a peak. Thanks. No real rush.
PRO
USA
#98  
You bet I'll save it out...very simple..
#99  
Still recommend you get the USB/Dynamixel interface, plus Robotis.us has a lot of helpful information. Glad to see DJ adding support for this, good job!
PRO
USA
#100  
@69developer, i ordered that and the arbotix controller and the piggy back board for the bigger dynamixels. Just to test with. The Dynamixel plug in has a scaling implementation that works ok for my needs but very interested in exploring these servos full potential for future projects, as shown in this video:



#101  
Yeah that's a super cool video, but at present we can't get feed back. I will say I'm pretty damn happy with what I've got accomplished.
PRO
USA
#102  
Yes for sure, so happy i can include these servos with the EZB. I did some testing for an hour or so last night. The scaling took me awhile to figure out. In fact just a couple minutes ago i was playing again and finally figured out how to get complete 360 at the fine resolution of 4096..which is overkill really. I used 1024 and that would be more than i would need. But its just opens a whole new door for me. Feedback would be awesome, but maybe thats not possible or a future implementation. Expect BIG things from me in the future..ha.
#103  
Feedback should be possible. The UARTs are 2 way.

Whether DJ gets to it before another developer takes up the reins and writes the plugin is the question. Lots of stuff on DJs todo list, and supporting 3rd party stuff is great, but tends to get less attention (reasonably so).

Alan
PRO
USA
#104  
Yes the man has a lot on his plate. It's always why I'm appreciative when he takes the time out to work on a request. Count the CEOs that participate in their companies forums?!
#105  
Yeah and a special thanks to Will for bringing a dead horse to beat!
PRO
USA
#107  
I tried a quick test with the IOTiny on D5 and I can't turn on the led or get the servo to move. Am I asking too much of the IOTiny?
#108  
I can't locate the datasheet (posting from phone again), but I don't think the uart on the iotiny is on D5.

Alan
PRO
USA
#109  
Thread: Post #9
https://www.ez-robot.com/Community/Forum/Thread?threadId=9789&page=1

Quote:


The IoTiny does not have input UART, however. The IoTiny has output UART on all 8 digital pins, but no input. You would have to communicate with i2c to arduino.


If i understood well, the IoTiny does not have UART ports.

ARC help:

Quote:


Digital Port Output Baud Rates
The digital ports can output Serial, which differs from the UART. Using any digital port as a Serial Output command can be done by using the SendSerial() command. Using a digital port this way does not include an input buffer. For input buffers, use the UARTx functions.


Code:


SendSerial( digitalPort, baudRate, data, ... )


Dynamixel @ IoTiny:

The Dynamixel plugin code uses the EZ UARTxxxx API methods, to support the IoTiny needs to use SendSerial API method.

DJ can validate my assumption.
PRO
USA
#110  
Great info! Thanks!
PRO
Synthiam
#111  
Correct - the IoTiny does not have a hardware uart.

The plugin can be modified to use one of the digital pins, however. The only limitation would be the max baud of 115,200. That baud should not be a problem, as it's still considerable Fast and actually will be more reliable than the default 1,000,000bps of some dynamixel servos. The 1mbps actually has quite a bit of frame errors in my testing IF data lines are routed near devices causing electrostatic interference (i.e. Motors and high frequency CPUs or power supplies).
PRO
USA
#112  
Got it, thanks DJ!
PRO
USA
#113  
One request, now that I'm dealing in 4096 positions, any chance you can create an additional input (ARC, not the plug in) to go with the arrow and drop down for inputting min and max positions. Just to type in the position in a field?
#114  
One thing I noticed, and it is no fault of ez robot, is .. that due to these servos not having a physical stop in them it sometimes makes " homing" very difficult. What I think is happening is that the servos want to go to there " home" position without regard to direction. For example my init script tells both elbows to rotate home, and up so the arms don't get run over by its treads. During power down the arms fall to the ground. If the elbows rotate outside of the tread ,the next time powering up the elbow tries to spin backwards effectively trying to beat himself. So basically I just make sure both arms are in a " parked" position where gravity can not affect position during power off.
PRO
USA
#115  
Interesting. That could make for some serious accidents in some cases. How are you keeping your arms in a certain position in power off? Do these servos roll back with no power under load? Like your arms slumping down. How much load are on them?
#116  
Yes exactly arms slumping down. What I did was change the angle of the shoulder joint forward so when elbow joint is in it's up position the lower arm rests on top of the upper arm, kind of.
PRO
USA
#117  
Got it. I'll have to do some testing on that. Could be dangerous the bigger my servos get.. watch the video from trossen where they break chicken bones with dynamixels.
#118  
Hahaha...don't be a chicken and post the link!

Great to hear you got some cool stuff to come in 2017!
Looking forward to see what you are up to...

I am waiting for my 3D printer being shipped to get stuff going...
*superexcited*:D
PRO
Synthiam
#120  
That's disgusting. I modified your post so it doesn't show up as a preview video in the news feed.
PRO
USA
#122  
@Dj, good idea.

But does demonstrate the importance of how powerful these servos are! Use caution to keep from maiming yourself !
#123  
@fxrtst - so how did your Dynamixel project work out?
PRO
USA
#124  
It's still n progress. It will develop over the next couple of months. But so far I love the high resolution. Even without the feedback, it's a superior servo for large projects.
PRO
USA
#125  
@dj,

I don't want to create another thread as this is still on topic. Do virtual servos support invert direction? I can seem to get a dynamixel to invert on the camera panel.
PRO
Synthiam
#126  
I don't think so. I'll have to look at the plugin code and see
PRO
USA
#128  
Couple of things. Just got my MX 64ATs and updated to the newest version of ARC. Now not sure if it's coincidence but I can't get the dynamixels to move anymore. Could anyone one with this set up confirm the plug in is still working. I'm up to date with the plug in as well. Tried with both my new dynamixels and my mx28. Nothing at all.

So many variables in this set up want to rule out broken plug in first before I run down thru the list.
PRO
Synthiam
#129  
Check baud rate on servos.
PRO
USA
#130  
Yeah I did thanks. Was actually computer wasn't updating comm ports and using a burnt up a dynamixel (ouch! $$$$)! So a perfect storm of issues..

I switched laptops and new dynamixel and working again!

Also dynamixels do invert direction as talked about above thread! Yay.