RoboSavvy Forum

new controller coming together, update...

2006-12-06T20:54:07+01:00

JonHylands wrote:
I have run a program on my gumstix, that talks to the Bioloid bus (and a single servo) to both ping the servo, and go through a sequence of moving the servo arm.

Great work, Jon! You should consider writing an article for Servo magazine (and letting me proof-read it for you ).

Best,
— Joe

Statistics: Posted by Joe — Wed Dec 06, 2006 8:54 pm

new controller coming together, update...

2006-12-06T05:10:03+01:00

Well, I have success.

I have run a program on my gumstix, that talks to the Bioloid bus (and a single servo) to both ping the servo, and go through a sequence of moving the servo arm.

I'm going to talk to my brother about posting the code for the robostix - he has marked the source as dual-licensed as either GPL or BSD, so I don't imagine it will be a problem.

To update - the gumstix is talking to the robostix over the 115,200 baud serial port, and the robostix is talking to the Bioloid bus at 1 Mbps (using the other hardware UART). With this setup, you don't need any external hardware from the robostix - the Tx and Rx pins on the robostix can be tied together to the Bioloid bus line.

- Jon

Statistics: Posted by JonHylands — Wed Dec 06, 2006 5:10 am

new controller coming together, update...

2006-12-05T21:45:43+01:00

I just today got a couple of AX-12 servos in the mail, so once I get my hardware harness together, I will post the results of trying to get my gumstix to talk to the AX-12 bus through the robostix...

- Jon

Statistics: Posted by JonHylands — Tue Dec 05, 2006 9:45 pm

new controller coming together, update...

2006-12-01T21:01:48+01:00

Juha wrote:
I got the cameras (I ordered 2) last week , they seem very, very cool I think it took about a week to get them all the way over here (to Finland).

I did the wirering for my controller yesterday, I'll probably try to code the protocol this weekend.

Note that you can boost the speed of the communications with the camera way above the 115K documented in the manual. If you set both timing values to 1, it will run at 921K...

- Jon

Statistics: Posted by JonHylands — Fri Dec 01, 2006 9:01 pm

new controller coming together, update...

2006-12-01T10:11:43+01:00

JonHylands wrote:
It would pretty much have to be in the AX-12 itself. The offset you're talking about is almost certainly in the CM-5, and is something completely different.

Yes, it's probably cm-5 which is taking care of the offsets.

JonHylands wrote:
limor wrote:Thank you Juha for all the links to these amazing embedded products.
Especially the embedded video camera with serial output..

Turns out you can also buy this camera from a place in the US:

http://www.electronics123.com/s.nl/it.A ... tegory=241

This is actually where I ended up ordering them from.

I got the cameras (I ordered 2) last week , they seem very, very cool I think it took about a week to get them all the way over here (to Finland).

I did the wirering for my controller yesterday, I'll probably try to code the protocol this weekend.

Joe wrote:
Has anyone yet tried controlling an AX-12 from a PC? Seems like it should just require adapting the RS-232 voltage to the right levels, and then a small bit of programming.

Not directly, I have my controller in between.

Yes, signal levels is one thing (can be done with a single chip) and another thing is that you need a control signal to choose the direction of the bus. But I think yo might be able to use one of the "extra" signals in your rs232 port for these (CTS, RTS what ever I can never remember these ). So this should only take 3 components.

Statistics: Posted by Juha — Fri Dec 01, 2006 10:11 am

new controller coming together, update...

2006-12-01T01:58:05+01:00

My brother isn't doing anything other than writing a simple C program that runs on the Mega128 on the robostix. I'm the one who will be interfacing the gumstix/robostix with the Bioloid bus.

The way he set it up is to just connect the Tx and Rx on the Bioloid side of the robostix. The Rx pin gets the stuff that the robostix transmits down the bus, but he just discards that.

As far as power, I will be using a 9.6 volt NiMh battery to power both the bus and the robostix. The robostix provides power to the gumstix throught its voltage regulator, so its taken care of.

- Jon

Statistics: Posted by JonHylands — Fri Dec 01, 2006 1:58 am

new controller coming together, update...

2006-12-01T01:25:11+01:00

JonHylands, I'd be interested to see how your brother is planning to connect the Robostix to the Bioloid bus and how he powers the Robostix, Gumstix and Bioloid bus.

thanks!

Statistics: Posted by limor — Fri Dec 01, 2006 1:25 am

new controller coming together, update...

2006-11-30T20:06:47+01:00

Well, what I'm writing for the gumstix will also work for talking to it from the PC, since the robostix is just acting as a go-between. In fact, the code I'm writing for the gumstix is in Squeak Smalltalk, and that code will run on my Windows XP laptop with no changes.

- Jon

Statistics: Posted by JonHylands — Thu Nov 30, 2006 8:06 pm

new controller coming together, update...

2006-11-30T19:12:10+01:00

Sounds great — everyone please keep up the great work. In the LEGO Mindstorms community, there are a couple of garage businesses that seem to be making a decent living (or at least supporting their habit) by developing and selling custom Mindstorms-compatible components. See Mindsensors for example.

I can easily imagine the same thing happening in the Bioloid world, though in this case, there's clearly pent-up demand for a replacement controller as well. But the Bioloid wiring and serial protocol would be the underlying glue that makes it all work together.

Has anyone yet tried controlling an AX-12 from a PC? Seems like it should just require adapting the RS-232 voltage to the right levels, and then a small bit of programming.

Best,
— Joe

Statistics: Posted by Joe — Thu Nov 30, 2006 7:12 pm

new controller coming together, update...

2006-11-30T17:01:53+01:00

limor wrote:
Thank you Juha for all the links to these amazing embedded products.
Especially the embedded video camera with serial output..

Turns out you can also buy this camera from a place in the US:

http://www.electronics123.com/s.nl/it.A ... tegory=241

limor wrote:
We may be using it in conjunction with the Robostix into which the Gumstix snuggly fits in and which has an Atmega128 like the CM5 and the MavricII. Robostix can probably electrically interface with the Bioloid bus and it has many exposed analog and digital inputs for extra sensors and it can power the Robostix (which has no power interface).
[/url] are sold on this site!

My brother is writing a bus interface for me for the Robostix - basically, it uses the two hardware UARTs, one to talk to the gumstix at 115K, and the other to talk to the Bioloid bus at 1 Mbps, with 128-byte buffers in both directions. I should be getting a couple AX-12 servos in the next few days, so I will let you know how it works once I hook mine up to the gumstix/robostix combo.

- Jon

Statistics: Posted by JonHylands — Thu Nov 30, 2006 5:01 pm

new controller coming together, update...

2006-11-30T13:48:44+01:00

According to the manual:

Address 0x14~0x17 Calibration. Data used for compensating for the differences between the potentiometers used in the Dynamixel units. The user cannot change this data.

It would pretty much have to be in the AX-12 itself. The offset you're talking about is almost certainly in the CM-5, and is something completely different.

- Jon

Statistics: Posted by JonHylands — Thu Nov 30, 2006 1:48 pm

new controller coming together, update...

2006-11-30T10:07:09+01:00

Hi guys,

My project is slowly advancing; I've been mainly searching for right components, working on the application architecture / API and so on.

I had one thing I was hoping someone could answer: in the Bioloid ax12/cm-5 system, on which level are the actuator offsets stored/applied?

The ax-12 manual shows that the control table shows:

20(0X14) Down Calibration(L) RD ?
21(0X15) Down Calibration(H) RD ?
22(0X16) Up Calibration(L) RD ?
23(0X17) Up Calibration(H) RD ?

But these ones are (at least in the manual) marked as read only access?

I'm just wondering at which level I should handle the offset, since I'll probably need them.

So if anyone knows, if it's for example the cm-5 which stores them, and processes all the move request adding the offset or something...

Cheers,
Juha

Statistics: Posted by Juha — Thu Nov 30, 2006 10:07 am

new controller coming together, update...

2006-11-10T11:08:24+01:00

I am using a PX832A (AKA Propeller) processor and it runs fine at 1Mbps.
Although the robot can be programed in Spin/ASM using this board I am currently working in a interpreter for BCP programs. I support every CM5 internal register. Now I need to interpret BCP commands. Fortunately once tokenized the commands are easy to interpret. What I want to have is a backwards compatible CM5 replacer.

I plan to support the remote commands too.

It is interesting how many projects people have started for replacing the CM5!

Statistics: Posted by inaki — Fri Nov 10, 2006 11:08 am

new controller coming together, update...

2006-11-10T01:48:22+01:00

JonHylands wrote:
I'm planning (once I buy a kit in the spring) to toss the CM-5, and interface the servos & sensor(s) to a gumstix.

Do you guys have any advice - things to watch for?

Does the schematic as posted in the AX-12 manual work for using a standard Tx/Rx interface on a micro-controller?

works for me - have interfaced dynamixels to a PIC16F86 and to Atmega128 using this circuit

What speed do you use to talk on the bus?

with the PIC I could get 115200 (just) - 57600 was more suitable ( no UART so I was bit banging and it was using all it's horespower just keeping the communication going with 4MHz xtal. I was trying to make a device like the AX-S1 but with ability for me to add sensors as desired and thus enable me to use the CM5 as the main control but in the end I gave this up - the PIC was just not up to it - and decided to replace the CM5 with something easier to hack)

with the ATMega128 running with 16MHz xtal I am using 1MBaud (same as default CM5)

hope this of use

Statistics: Posted by jonkster — Fri Nov 10, 2006 1:48 am

new controller coming together, update...

2006-11-10T00:38:55+01:00

Great topic for discussion!

Thank you Juha for all the links to these amazing embedded products.
Especially the embedded video camera with serial output.. and Java embedded o/s

CM5's only shortcoming is it's lack of analog input pinouts. Please check out the thread about Pepperm's Bioloid Sensor Board as it is a simple solution to address this particular problem.

CM5 also has "only" 16mhz of processing power hence adding some CPU power can allow to do some on-board image processing and -- my favourite -- dynamic control.

I've been working with students in University of Lisbon to attach a Gumstix to the Bioloid bus in order to dynamicly control of the robot utilizing loads of sensory data (sort of like what PWM gyro modules do to stabilize the KHR and Robonova but utilizing 100 sensors instead of 1).

Turns out that the Gumstix is indeed very powerful but there's a lot of learning and discovery to be done like running a virtual linux in Windows, linux bluetooth magic, cross compiling and installing the operating system into its flash memory etc. It does not come with a 300-page document but is rather supported by a community wiki and a very 90's mailing-list with an unsearcheable archive. but this little 400mhz Xscale stix is so fast that it will certainly be able to run some neural addaptive controller and digest 10000 sensor events per second while updating the AX-12's at 100hz. so it is worth all the trouble.

We may be using it in conjunction with the Robostix into which the Gumstix snuggly fits in and which has an Atmega128 like the CM5 and the MavricII. Robostix can probably electrically interface with the Bioloid bus and it has many exposed analog and digital inputs for extra sensors and it can power the Robostix (which has no power interface).

A RoboSavvy blog is in the making and the project will be documented there.

BTW: Both AX-12 servos and AX-S1 sensors are sold on this site!

Statistics: Posted by limor — Fri Nov 10, 2006 12:38 am