Trossen Robotics Community

[Project] This Ultrasonic Transducer Sensor is Amazing

lusil — Wed, 16 May 2012 06:13:33 GMT

I had the opportunity to see the new HRLV-MaxSonar-EZ in operation Wednesday evening this past week. All I can say is WOW! This sensor is truly an amazing piece of engineering work. The most exciting part of the demonstration that I saw was the engineer set up an MB1010 (in free run operation 20Hz) pointed directly at the HRLV-MaxSonar-EZ (in free fun 10Hz operation). The HRLV sensor maintained stable 1mm reported resolution +/- 1mm to a 1 meter target (on a small occasion, there was a noise blip of 2 to 4 millimeters change). The multi sensor operation of this test was the equivalent of running three 10Hz operation sensors because of the 20Hz operation of the LV-MaxSonar-EZ sensor. I have never seen this type of reported accuracy in a low cost Ultrasonic sensor.

As a manager I then saw the demonstration of the temperature compensation which was very impressive. The engineer had the HR-MaxTemp external temperature sensor attached and the HRLV-MaxSonar-EZ sensor reported range matched a laser range finder reported range in millimeters at one meter. For demonstration, he took the temperature sensor in his hand and started to warm it up by just holding the HR-MaxTemp. The sensor immediately started to apply the compensation for temperature to the readings and I could see the change in the reported range. Then once the HR-MaxTempUltrasonic sensor cooled down, the HRLV-MaxSonar-EZ sensor was reporting accurately to the millimeter again.

Production of the HRLV-MaxSonar-EZ sensors started this last week. We are finishing all the production fixtures and test sets. The datasheet is in the engineering department and is being handed back and forth for revisions. We have the website going through final revisions for publishing and all internal system updates are being finished for this new and exciting product.

The HRLV-MaxSonar-EZ sensor is truly a revolutionary sensor for only $34.95. Watch our website for the ability to place preorders within the next week. The sensors will begin shipping about 1 week (or less) after preorder is posted. We look forward to providing this sensor solution to you!

[Question(s)] Global frame to local frame

naveen_633 — Fri, 11 May 2012 04:03:24 GMT

Hello friends
Iam naveen and new to this forum.I have a question regarding the transformation matrix from world frame to the base frame of a Spatial serial manipulator. The frames are attached like this. The Z-axes are along the link lengths. The Xi axis is oriented such that Xi = Zi X Zi+1 and Y-axis such that it completes a right-hand system. For the base frame of manipulator the Z-axis is along the First link but the X and Y axes are arbitrary. My world frame is at (0,0,0) at some distance and different orientation to that of robot base frame. World frame orientation is along unit vectors xo = [1 0 0],yo = [0 1 0] and zo = [0 0 1]. I want to know how to calculate the Transformation matrix from world frame to manipulator base frame.To make it clear further the First link is located at some distance and oriented differently with respect to world frame.Iam sucessfully able to calculate the end-effector position withrespect to base frame.But iam not able to transform it withrespect to world frame. I tried in many ways but could not succeed.I will describe the context of the problem below.

Actually iam modelling the backbone atoms of a RNA molecule as a serial chain hyper-redundant manipulator. The atoms are modelled as joints and bond-lengths as links. The bond-lengths and bond-angles are constants and torsion angles are the variable parameters. The frames are attached as described in the first paragraph. The Z-axes are along the bond-lengths. The Xi axis is oriented such that Xi = Zi X Zi+1 and Y-axis such that it completes a right-hand system.For the first bond the Z axis is along the bond but the X and Y axes can be taken arbitrary.
The DH parameters are defined as follows. a =0 always for this problem as the bonds intersect(hence the Z-axis), d- distance between X-axis is here is taken as the bond-length, theta is the torsion angle. All DH parameters are calculated from atomic positons of atoms.
Initially iam trying to calculate the end-atom position(end-effector) withrespect to first-atom(base-frame),for some known values of theta. This iam sucessfully able to do. But Iam not able to calculate end-atom position withrespect to world frame. So i want to know the transformation matrix which relates frame attached to first atom(note that the Z-axis of frame attached to first-atom is oriented along the bond from first-atom to second-atom but X and Y axis are arbitrary) to the world frame.

Iam assigning frames in a similar manner as given in the lower half of this page:http://planning.cs.uiuc.edu/node111.html but note that my world frame is different from that described there.

Thank you for your patience reading of my long describtion of my question.

[Question(s)] Arbotix & I2C

sarendt — Fri, 11 May 2012 03:20:26 GMT

Does anyone know how to address the I2C lines on the Arbotix? I have seen something like this (code below) online, but I don't know how this "knows" where to send/recieve I2C data... The arbotix manual isn't super clear on I2C communication and I haven't been able to find the much in the way of example code. I'm using the RM-G146 and am fairly confident I have it wired correctly.

Code:

#include "Wire.h"     

#define gyro_addr 0x68 

#define magne_addr 0x30 

#define acce_addr 0x18   

 

 

void setup()

{

  Wire.begin();     

  Serial.begin(9600);

}



  void getdata_acce(byte *a, byte *b)

  {

   

    Wire.beginTransmission(acce_addr);

    Wire.send(0);   

    Wire.endTransmission();

    

   

    Wire.requestFrom(acce_addr, 2); 

    *a = Wire.receive(); 

    *b = Wire.receive(); 

  }



void loop()

{

 byte aa, bb;    //variables for storage

 

 getdata_gyro();

 getdata_acce(&aa, &bb); 

 getdata_magne();

 

 

 Serial.print('a= ');

 delay(300);

 Serial.print(aa, HEX);    //prints the value of aa

 delay(300);

 Serial.print('\n b=');

 delay(300);

 Serial.print(bb, HEX);    //prints the value of bb

 delay(300);

}

I also read that the address listed are wrong, 8 bit vs. 7 bit, I'm not sure how to tell if thats correct or not, but I assume I can figure that out once I get the communication address/s figured out.

Thanks!

Cheers,
Scott

[Question(s)] Reading Wrong Position Values from AX-12 (C++)

robotpanda — Fri, 11 May 2012 02:44:04 GMT

Hi All,

I'm reading the wrong current pos values from my AX-12s. (Pan and tilt) It keeps spitting back the same value (- 52.17, +52.17) Even though I'm able to send it commands and move it.

Any ideas what could be wrong? My code for reading pos is as follows:

get_position(int id){

struct DXL_inst_packet instPacket;
struct DXL_status_packet statPacket;
instPacket.id = id;
instPacket.length = 4; /* Read length */
instPacket.instruction = INST_READ;
instPacket.address = P_PRESENT_POSITION_L;
instPacket.parameter[0]= 2; /* I want to read two bytes */

send_packet(&instPacket);

if(read_packet(&statPacket)!=-1)
{
int position_read_from_servo_hex = ((statPacket.parameter[1]<<8)| statPacket.parameter[0]);
if(id==PAN_ID)
return ((position_read_from_servo_hex-CENTRE_HEX_PAN)*POSITION_HEX_xTHIS_GIVES_POSITION_ RADIANS); // Return radians
else if(id==TILT_ID)
return ((position_read_from_servo_hex-CENTRE_HEX_TILT)*POSITION_HEX_xTHIS_GIVES_POSITION _RADIANS); // Return radians
}
return -1;
}

Any help would be much appreciated! I'm using Ubuntu to compile all this :D

Thanks again! :D

[Question(s)] Forum Search Problems

sarendt — Fri, 11 May 2012 02:18:50 GMT

Has anyone else noticed a problem with the search? I have been working on hooking up a I2C sensor to my Arbotix and I know this is the best place to look for all things Arbotix... I tried the search and didn't find anything so I assumed there wasn't anything to be found. A few days later I used google and noticed a trossen link showed up so I clicked on it. There it was, clearly in the subject line "I2C" ... http://forums.trossenrobotics.com/sh...781-I2C-Header

Even worse was below it were "similar" posts that also clearly have "I2C" in the subject line...

Am I miss understanding how search works, or miss using it?

Thanks!

Scott

Crazy question: "Cheetah" walker?

jwatte — Wed, 09 May 2012 23:00:51 GMT

I'm looking at all the walkers, and the significant challenges involved with walking with any degree of speed. Even the "big dog" (which apparently now has Army funding) isn't particularly nimble, and it's faster than most bipods/quads/hexes I see here.

Then I think about fast animal movement. Cats running on four legs, for example. The movement for that running seems a lot simpler, mechanically, than the deliberate balancing act that bipods/quads end up with. The draw-back is that the balancing is quite dynamic -- you can't "stop" in the middle of a movement, or you'll totally collapse.

Could a "running" robot be built with fewer moving joints? It seems you just need two joints each for the four legs, for a total of 8 joints, and you could get a running/leaping gait, assuming you can get enough force. You might be able to use something like a strong solenoid, rather than a servo, for actuation, to get a momentary compress/release force instead of steady torque. You could turn by actuating with different amounts of force -- or by having slight sideways bend, which would need a servo or two more at the head of the legs.

Has it been done? Am I crazy? I'm not in a position to try this out anytime soon, so I'm just kicking the idea around in my head for now.

[Question(s)] Can I use Robotis Dynamixel SDK to control dynamixels connected to CM-510

nsmoly — Mon, 07 May 2012 21:32:00 GMT

Hello,

Question about Bioloid's Dynamixel SDK (C++) from Robotis (could not find it on their site and no one from support is helping) :
Can I use Dynamixel SDK C++ functions to control dynamixels that are connected to CM-510 which is connected to PC via a serial link and USB2Dynamixel switched to RS232 mode? Essentially, the setup is PC->USB2Dynamixel->CM-510->dynamixels
I tried Robotis Read-Write code samples for Dyanmixel SDK and even though CM-510 blinks like it receives packets, the actuators are not moving. The RoboPlus Manager can control dynamixels with the same setup running on my PC.

Thanks
Nick

capture tag id - code to GET RFID TAG ID

priiya p — Mon, 07 May 2012 19:51:07 GMT

Hi,
I am trying to do a small project RFID based door lock system using PIC24H Mic, but I'm failing to interface the PIC24 and Red Bee RFID. Can you please help me.....?

How will the output at rx pin of REDBEE RFID be? I want to send the tag id to the PIC. How do I do this? Sample C code or Suggestions would be of great help !

I tried the following the below logic, but it didn't work.
Program:

/****I am trying to transmit the tag data from rx pin of REDBEE RFID to PIC pin RB10/RB11. But I couldn't get the tag id to the PIC, The LCD interface is working fine. I used some library functions, some of which I described briefly below *****/

A part of my code is :

uint8_t u8_c;
u8_c = inChar(); //get character
outChar(u8_c); // Write a character to the serial port
for (int i =0; i< 15; i++)
{
array[i] = u8_c;
}
outStringLCD(array); // display the tag on LCD
writeLCD(0xC0,0,1,1);

Function and its brief description:
1) uint8_t inChar(void)
/*** Read a character from the serial port.
This function blocks until a character is read. ***/

2) void outString (const char * psz_s)
/*** Write a null-terminated string to the serial port. ***/

3) void outChar (uint8_t u8_c)
/*** A system-dependent macro to output one character.
Write a character to the serial port.
This function blocks until a character is written. ***/

4) void outUint8Decimal (uint8_t u8_x)
/***Output u8_x as decimal value. ***/

5) uint8_t isCharReady (void)
/*** Determine if a character is ready to be read
from the serial port.
Returns: non-zero value if character is ready,
zero otherwise ***/

5) uint16_t inString (char * psz_buff,int16_t u16_maxCount)
/*** Reads a string into psz_buff, assumes psz_buff
can hold at least u16_maxCount+1 characters. ***/

6) #define CONFIG_INT1_TO_RP(pin) _INT1R = pin
/*** This maps an input internal to the PIC to
an input pin. For example, CONFIG_INT1_TO_RP(10) maps
the INT1 edge-triggered interrupt to port P, pin 10 ***/

For more functions available in library:
http://www.ece.msstate.edu/courses/ece3724/main_pic24/docs/_p_i_c24_support.html

Above functions reference links:
pic24_uart.h:
http://www.ece.msstate.edu/courses/ece3724/main_pic24/docs/pic24__uart_8h.html

pic24_uart.c:
http://www.ece.msstate.edu/courses/ece3724/main_pic24/docs/pic24__uart_8c.html

pic24_serial.h:
http://www.ece.msstate.edu/courses/ece3724/main_pic24/docs/pic24__serial_8h.html

Please let me know how could I write program to get tag ID to PIC ???? Please help !
Thanks.......

0.2" FSR integration with MAXON EPOS2 P

mihir — Mon, 07 May 2012 10:39:57 GMT

Hi guys can I integrate the 0.2" FSR with MAXON MOTOR'S EPOS2 P motion controller. The motion controller has two analog inputs and one analog earthing point.

HUGE SALE: Selling Robot Controllers, Speed Controllers, Relays, Servos, Motors, Big Motors, Joysticks

matter0464 — Mon, 07 May 2012 02:23:19 GMT

I have a ton of robot equipment i need to get rid of asap, Im looking for $1600/ OR best offer for EVERYTHING including 5 victor 883's and 5 victor 884's and 4 additional Spike relays (not in pictures)

If need be i can sell individually but it would be much easier to go as a whole :( The total cost of everything here is over $5000 its a steal.

Attachment 3989 Attachment 3990 Attachment 3991 Attachment 3992 Attachment 3993 Attachment 3994 Attachment 3995 Attachment 3996 Attachment 3997 Attachment 3998 Attachment 3999 Attachment 4000

Here is market price

Operator Interface = $349 x3 = $1047
Robot Controller = $449 x4 = $1796
victor 883 = $120 x6 = $720
victor 884 = $90 x6 = $540
spike relay = $34 x 6 = $204
Radio modem robot = $149 x 3 = $447
Radio modem operator interface $149
First CIM motor = $20 x 2 = $40
Total = $4943
**This does not include the 3 other robot controllers i cannot find a price for them.

Thanks for looking hopefully i can sell these they all function great i will definitively recheck everything before we close the deal.

To any buyers, Paypal would be great thanks.

Attached Thumbnails

I have about 10 victor 883's for sale

matter0464 — Sun, 06 May 2012 22:25:17 GMT

Hey guys,

I have a bunch of victor 883's (about 10 or so) im trying to sell them for a better laptop and for collage, im asking for about $90 each/Or Best offer.

I believe this is a good deal because new they cost $150+ and they are very rugged and work perfect. here is some info on them.

60A Continuous
Only weighs 4 oz.
Ideal for High Current Drive Motors
Safely handles high continuous current draws and extreme current surges.
Integral cooling fan ensures cool FET junction temperatures.
The low voltage drop ensures the motor receives maximum power.
up to 200A surges for 1 second and 100A surges for 2 seconds.
Reverse and Forwards at variable speeds (PWM controlled).

Please message me what you think, or email matter0464@att.net

[Discussion] Dealing with relative reality

jwatte — Sun, 06 May 2012 18:30:52 GMT

I'm a software guy for work, so I do hardware-ey things for hobby to get some variation. I ended up with robotics because it's hardware that requires software... If all you want to do is see the question, look at the last paragraph. Here comes the back story:

Right now, I'm converting an old RC truck (a Nikko that's one step up from the Radio Shack specials) to something that could solve a RoboMagellan course. I don't know if I'll actually ever compete, but it's an interesting challenge.

The main problem I'm working on now is the "relative scale" problem of mechanics. A flat floor or paved sidewalk is "flat" for a normal human, and also for an 18" long robot. However, a "cracked" sidewalk might still be "flat" to a human or bicycle or car, but is decidedly "bumpy" to a 2-foot robot. A front-yard lawn is "flat" to a human, but is quite "craggy" to a robot.

I have PWM control of my traction motors, and I have separate front and rear axle drives, each with a differential (but it's not four direct drive wheels.) I can turn this up to the point where I have good acceleration even over lumpy grass, and I can modulate it to provide a "rocking start" if I get stuck. However, the relative coordinate system of the robot rocks with it -- and even just going fast across the lawn, it bumps around by up to 20 degrees within a tenth of a second! This makes sensor integration very hard.
Similarly, if I tune PWM to just make some progress on the lawn, it will race away with wild abandon when it gets to a truly flat place, like that concrete sidewalk. (Good thing I have that remote stop :-)

I'm using AVR microcontrollers on perfboard for sensors and devices, a home-grown MOSFET 10A H-bridge (aw yeah!) for brawn, and will probably end up with Intel CPUs on Mini-ITX form factor for brains. For now, I have telemetry and remote e-stop through long-range nRF24L01+ modules, and some simple AVR-based behaviors. The goal is to use stereo vision based on two HD webcams, and a forward-firing laser to get a known "common reference point." If that doesn't work out, I'll fall back to single-camera vision.

But, what do I do about the problem that a "flat lawn" to me is a "jumbled rockscape" to my robot? Do I build a bigger robot? I don't want the platform itself to go much beyond 15 pounds, because the required drive powertrain will become crazy big, and the weight limit for the overall robot is 40 pounds. There's also price to consider, although I can budget saving hobby expenditures for a while if the right thing is available.
Or are there suspensions available for the sensor package itself? The truck already has a sprung suspension, but no shock absorbers. Some kind of Gimbal for the cameras and laser (and perhaps the gyro and GPS) would be nice, but that sounds complex and pricey.
Or should I attempt to do some crazy software-based motion compensation?
Or even just run the software fast enough that I can do the full 3D SLAM in real time while bouncing around? :-) (That'd be nice, but my cameras only go up to 30 Hz, and somehow I doubt this would be the most efficient approach)

Buying: 5 AX-12+ Servos

willwagstaff — Sun, 06 May 2012 06:43:07 GMT

PM Me if selling.

SELLING: XSENS MTI Development Kit - Brand New !!!

cillaelery — Sun, 06 May 2012 04:53:30 GMT

I am selling an XSENS MTI Inertial Measurement Unit. This unit comes with the development kit and is packaged in a very nice plastic case. The unit comes with all accessories including a USB Drive, all cables, the IMU, all documentation and the durable plastic case.

Here are a few pictures of the unit,

Details on this unit straight from the manufacturer can be found here:
http://www.xsens.com/en/general/mti-g

*** ALL REASONABLE OFFERS WILL BE CONSIDERED ***

Please feel free to contact me directly at 951-847-5913 or over email at cillaelery@gmail.com

Selling: Kvh cg5100 fog imu !!!

cillaelery — Sun, 06 May 2012 04:16:57 GMT

I am selling a KVH CG5100 Inertial Measurement Unit. I have extensive knowledge of IMUs and have worked with a large variety of different manufacturers. The KVH CG5100 is unequivocally one of the most advanced and top of the line Commercial and Military grade IMUs in the world.

Details on this unit straight from the manufacturer can be found here:
http://www.kvh.com/Commercial-and-OE...s/CG-5100.aspx

*** ALL REASONABLE OFFERS WILL BE CONSIDERED ***

Please feel free to contact me directly at 951-847-5913 or over email at cillaelery@gmail.com

Overview
CG-5100 – The Complete Position, Velocity, and Attitude Solution
The versatile new KVH CG-5100 Inertial Measurement Unit (IMU) combines proprietary technologies – highly accurate fiber optic gyro (FOG) based sensors coupled with industry proven MEMS acceleromete
rs – all within a compact single enclosure, providing reliability and long term compliance to customer specifications. Through its seamless integration of these two highly reliable navigation components, the CG-5100 provides a ground-breaking low-cost, small form factor solution for inertial measurement.
The KVH sensor engine of FOGs and accelerometers creates a flexible and efficient IMU, a high performance motion sensing package ideally suited for critical sensing applications and GPS integrated navigation programs. This strap-down inertial subsystem offers outstanding reliability and accurate 6-degrees-of-freedom measurement. The CG-5100 achieves its excellent performance by employing proprietary algorithms to a fully digital gyro
sensor output, enabling the system to characterise and correct for the effects of temperature and misalignment. The CG-5100 also affords the end user with a convenient and easy to adapt output in a fully digital RS-232/RS-422 format.

Key Features
• KVH’s patented Digital Signal Processing (DSP) FOGs for high reliability and
stable performance
• Highly accurate rate and acceleration data
• Designed to meet COTS requirements
• Measures roll, pitch, and yaw angular rates and accelerations
• Fiber optic gyro stability
• Affordable, compact design
• Excellent shock and vibration performance

Applications
• Antenna, optical, and camera stabilisation
• GPS augmentation
• Autonomous vehicles
• Drilling
• Navigation
• Motion sensing

SELLING: Brand New Ibeo Lux Laser Scanner with Advanced object Tracking software and all accessories !!!!

cillaelery — Sun, 06 May 2012 04:05:10 GMT

I am selling a brand new Ibeo Lux 4 layer laser scanner. The scanner comes with all accessories including the programming API and the advanced object detection and tracking software packages. The unit was purchased directly from Ibeo and sent from Germany less than 3 months ago. I have all original documentation and packaging. The unit is in perfect condition. The retail price of this package with all software and accessories is over 20,000 US dollars. An extensive personal robotics project that this scanner was to be utilized in cannot be pursued at this time and as such I have decided to sell this scanner. All offers are welcome.

I can be contacted directly at 951-847-5913 or over email at cillaelery@gmail.com.

More information on the unit can be found at the manufacturer's website here: http://www.ibeo-as.com/index.php?option=com_content&view=article&id=94&It emid=99&lang=en

Note: This scanner has been used by the winning team of the Darpa Grand Challenge and the Darpa Urban Challenge. This scanner is recognized as being the most technologically advanced multi-layer scanner in the world at this time.

Modelling and simulating forces of a robot

decimad — Sat, 05 May 2012 19:43:34 GMT

Hey guys!
I'm lately bending my mind into getting fit with delta robots (which admittedly might not be your focus judging from overall topics found here).
For constructing a real one, I'd like to get a hang of the moments and forces I'll have to expect during movement. Over at youtube I saw a video of a talented guy, who programmed a dynamic simulation model of a delta robot. No matter how much I thought about it, I imagine that a terribly complex task. From my understanding, the system sports coupled nonlinear differential equations (3 input, MANY constrained inner forces/momentums, 3 output).
Can you guys think of ways to break a real simulation into a manageable approximation? I was thinking on using normal forward kinematics of a given path and then somehow calculate the forces "backwards". But I always end up with coupled equations I cannot get broken up and the amount of forces and angles is discouraging when I don't have the feeling I'm on the right path.
Do you guys know an answer or can you point me to resources which could help me with this? I fully expect I'll have to spend some quality time on this!

Thanks in advance,
Michael

[Question(s)] Open source machine vision code to locate a human in a room?

roschler — Sat, 05 May 2012 14:07:45 GMT

Has anybody seen a resource covering specifically the use of machine vision for locating a human in a room, including cases where they may be partially obscured? I know about OpenCV and other machine vision packages, but I'm looking for a paper/library/code example that focuses solidly on identifying a human in a room; something that is readily integrated into code rather than being a rough idea that would require weeks or months of tweaking or enhancing to do a reasonable job of succeeding at the task. I'd prefer something that does not require binocular vision and can work with a single camera.

-- roschler

Hovis vs. Bioloid?

tom_chang79 — Sat, 05 May 2012 10:29:09 GMT

I recently started to notice this company called Dongbu Robotics, they sell this Hovis Lite humanoid robot, which almost looks like a Bioloid clone. Anyone own one of these?

From the few things I've read, it seems like their standard 0101 servos are *slightly* more featured than the AX-12+, but it's a bit scary how close their specs are.

Is Hovis sourcing their parts from Robotis through contract manufacturing, or is it the other way around? Their humanoid seems a bit sleeker too and I like how they handle the joint area.

Some concern that came to mind however:

1) Software support? Will the Hovis' software get support like Robotis' stuff? Robotis seems to be very good at supporting their products outside Korea.

2) What if you break a gear in the actuator? Robotis has a ton of support and distributions everywhere to get spare parts, more servos. Even though Dongbu's bot looks and seem amazing, I think their distribution needs more maturing.

I'm almost tempted to get one, but that would mean taking in another bot into the fold, which I have no time for. I think it may be time to sell off one of my bots before I get this one.

I really would love to wait for their Hovis "heavy" (don't know if that would be the next step for Dongbu), where instead of their 0101 actuator, they use their 0201 actuator. The fact that you get bracket color choices is pretty awesome too, no need to pull out the dye and mess up the kitchen!

Sorry for the copy and link of a huge image, it's straight off their website, and it's one huge image!

[Question(s)] where in the Arbotix AVR code is it talking to the XBEE serial port?

stephen.hazel — Thu, 03 May 2012 22:08:14 GMT

Ok, I'm making slow progress on my bluetoothed android phone to bluetooth bee'd arbotix board.
Almost got the android app to pair to another and sending back and forth some text.
Then I try android=>bluetooth bee=>arbotix.

I went browsing through arbotix-0014.zip and couldn't find WHERE in the heck it's talking to the
X BEE's serial port.
Can somebody point that out to me, please? Like a .c filename and path within that arbotix-0014 dir?

From what I'm gathering, ya have one little arduino app on the AVR and it doesn't change much if at all.
It's loading servo specs=>flash=>XBEE serial port=>other PC connected XBEE=>pythonSerial_WhateverYaCallIt=>python GUI, right?

I see where it's doing the AX12 serial bus. But not where it's messing with the XBEE one??

thanks for any pointers,

...Steve

[Project] Hi all some suggestions on my servos

nagash3 — Thu, 03 May 2012 19:02:37 GMT

Hi all guys
Its a long time I read this forum and I really like it.
I'm Luca from Italy and I've a looooong lasting project for a biped (maybe for a mech if I success).
I'm writing this post to ask your opinion on what I've built in this long time.
this is my first experiment

its a hitec 805Mg based servo

I worked a lot on it and I hope I obtain something utilizable

torque seem to be good, the motor itself can push really harder than this but geartrain can't support it, I first try with a bigger 50Kg balance?? and a 1 inch horn but the servo broke it so I think to put a longer arm (10cm) and use a little digital balance??

I know this test is ....useless... but I do it just for fun

So What you think ? Do you think this will work in a biped? does I miss something?
thank you a lot bye
Luca

SELLING: Dynamixel EX-106+ Robot Actuators

Ryan — Wed, 02 May 2012 18:36:02 GMT

I'm selling five (5) Dynamixel EX-106+ Robot Actuators. I had an event that I needed backups for, but didn't end up using them – but unfortunately too late to return them. They are brand new, unopened, in the original boxes. Trossen retails them for $500 ea., but I'm willing to part with them for $450 shipped (US) each, or $400 each if you take all five.

Please contact me at ryanwilsonjames@gmail.com if you're interested. Thanks!

PDF is unreadable - Robot Controller Joystick - Medium -3D

coreyfro — Wed, 02 May 2012 03:28:21 GMT

This PDF is trashed and I need measures for a project.
http://trossenrobotics.com/images/pr...s/OE-OM301.pdf
http://www.trossenrobotics.com/p/medium-robot-controller-joystick-3D.aspx

We're ordering a bunch of these to control the head of the Serpent Mother and other applications:
Attachment 3974

Can we get a better copy of the PDF?

Attached Thumbnails

How to decide run current and hold current in stepper motor

KevinQ — Tue, 01 May 2012 20:12:23 GMT

I am programming a motor controller where I have to specify the run current (coil peak current) and hold current (coil hold current) of the motors. The motor I used is a bipolar stepper motor, with a whopping 1.86Kg/cm of stall torque at 1.5Amp current (0.75A per winding) at 1.8 degree stepping angle.However, the table in the specification makes me confused: It lists a different current for a different torque.Here is a link to that motor controller http://www.nex-robotics.com/products...per-motor.html.How could I determine run current and hold current from this specification?

ax-12 motors voltage?

gwntd — Tue, 01 May 2012 05:48:58 GMT

Hello, I have a quick problem. I'm trying to connect 4 ax-12 motors together. However I don't think there is enough power to power all 4 motors at 10v. I can power up to 2 motors only. How much voltage should I give to be able to power 4 together?

Or do I HAVE should I split it into 10v for 2 motors each? I would perfer not to do this option

Also these motors act in parallel when connected?

Any suggestions in what I can do? I don't want to blindly blow the motors somehow.

Thanks