Sienna's Random Robot Thread!

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61

The torque on the digitals is ~33% more for the main reason. (I can’t afford 5990s yet!)

But also, I am going to be setting all the center and end points on the servos, as well as reversing one side of the bot. This should make my software tasks easier.

62

I usually use a direction multiplier so I can use the same values for both sides of a robot. I have 1 for the normal value side and -1 for the normally negative value side. It makes it easier to figure changes rather than having to reverse everything in my head all the time. :wink: My brain does not like reverse. :wink: :wink: I need to do that modification to MsBRAT’s code.

8-Dale

63

Updates:

I canceled the order for the HS5625MGs, and replaced them with HS5645MGs. I also bought 6 HSR5990TGs. So, in a week or so, I should have a total of the following servos:
6 HSR5990TG
6 HS5645MG
4 CS160 (aka HS5625MG w/o programming)
2 S3004
2 S3151
So, not a bad collection I am starting… although I am still 6 “real” servos short of building my Phoenix. Oh well, in time (those 5990s hurt!).

In the meantime, today was a Lynx day! (I love the days when UPS delivers goodies from LM!) So, I have assembled my first LynxMotion robot, although it hasn’t been programmed yet.
http://www.siennahanon.com/Robotics/Sienna_Brat_JR_1.jpg

http://www.siennahanon.com/Robotics/Sienna_Brat_JR_2.jpg

64

looks very good, personally I think LM should also include a BRAT jr in their product line for those really tough on robot money, and who want to a) enter the world of robotics with a simple bot, or b) eventually upgrade to the BRAT - or for both those reasons.

Also I like the way you used two ASB-16 instead of two ASB-04 and ASB-11. Looks good BTW 8)

65

I like that too. It’s cool when people build things that I hadn’t even thought of. It’s happening more and more, and I consider that the true sucess of the SES. Great job Sienna! 8)

66

It’s nice!

Would, with those servos youre gonna have lots of torque!! :laughing: Continue like this, youre going the right way.

67

:desk :desk :desk

I need serial output to adjust servo values to find the center of my servos, right? So, after trying vainly everything in my power to get HSERIAL to work over the programming port, I finally make the connection that all those searches that say the hardware serial port is on P14 and P15.

Which means I have no way of of hooking up my computer to the serial port on the board. And then of course, I lose my C button and LED, so now I guess I will have to implement the control over serial too. :unamused:

So, meanwhile I am at a complete halt because I do not have a level shifter, which is now on order. sigh

(It would be a nice feature to have on serial port constrained systems, the ability to send and receive over the programming port to the terminal… now I am happy I got the quad port card, cause I can see these serial needs adding up!)

Has anyone managed to get DEBUG mode on the Pro to play nicely with HSERVO? I swear, everytime I step to the next break point, all my servos react randomly, and now that they are assembled into something, I fear hardware damage if I keep using debug mode!

68

Yeah, so I really need to search the forums more… Apparently you CAN use those programming ports as a soft serial port. (oops!) For some reason I get garbage inserted above 19.2k, but 19.2k is fast enough to do servo centering :stuck_out_tongue:

And also apparently, everytime you connect to the device in the IDE, the micro resets. Oh well.

69

You just need to send a 1.5ms pulse to each servo to get it to its center point. If you are using an SSC-32, just send “# P1500” to send the servo on to the center.

8-Dale

70

No, I need a “center” point 7.5degrees off center, because their spline pattern and such isn’t lining up with the SES stuff how I want it.

So, I need an “adjusted” center value.

71

To find the actual mechanical center of a servo, you need to decrease the position value until the servo hits its internal hard stop. Then increase the position value until the servo once again hits its internal hard stop. The mechanical center of the servo will then be the servo position that is the middle value between the low position value and the high position value.

72

You’ll probably want to make up a set of offsets to be saved in the 'bot. This can take care of the 7.5 for the horns.

The data could be added to the program, or EEPROM, if you have it.

Alan KM6VV

73

Started to do some work with the tripod today…
http://www.siennahanon.com/Robotics/tripod_1.jpg

At the moment, it is using 1 SportBEC powered by a 7.2V NiMH. I will be adding two more SportBECs, one for logic (and I am only using a SportBEC because I want to be able to use it for other things in the future), and two for servo power. You can see the 3S 950mAh packs that I will be using in the future. (they are small yes, but they are already around, and their charger, so for now the cheap route is the better route)

I am still debating on whether to put them directly in parallel, or put them in parallel using diodes so that they can’t drain into one another.

74

For HSERVO, it’s easy to get to your approximate position. This would be +/- 9000 for for a full 180 degrees of travel with 0 being approximate center. It’s rather convenient in that you can just multiply the angle by +/- 100 to get approximately to where you want the servo to be and fine tune from there. +/- 7.5 degrees would be approximately +/- 750 from center. There is a similar formula for using an SSC-32 (+/- 900 for full 180 degrees of travel).

That’s about as easy as it gets. :slight_smile:

8-Dale

75

Neat design. What is this tripod for?

76

There is no purpose to it, other then other people on the forum saying it can’t be done, and as a holdover while I save money for things like a new soldering iron and another batch of servos to round out 18…

Thats all :smiley:

I got the legs on this evening! Wasn’t happy with how it looked, so I completely redid it… well kinda:
http://www.siennahanon.com/Robotics/tripod_2.jpg

Now, I would love to play more, but I have to make some stupid powerpoints for a stupid presentation about a design that doesn’t exist… sigh… The sacrifices one must make to keep making money for bots… :frowning:

77

wow i really think you have a working design there… ive never seen a tripod so i have no idea how this is going to walk.

Also, are those 11.1V batterys? isnt that a little much for the 5990’s? or do you have a regulator?

78

I rarely listen to people telling me “it can’t be done.” I’ve done quite a few things before I knew it could not be done… :smiley::smiley: Robotics is an experimental thing by its very definition, so EXPERIMENT! :smiley::smiley: I still hope to eventually build The BiPod I designed, but just can’t afford the servos to fill the brackets. I want to use a minimum of HS-645MG servos, because I don’t think it has a chance of walking otherwise.

Very cool! Be sure to get videos to document your progress. :smiley: We loves videos… :smiley::smiley:

I wish there were more women involved in robotics! You rock, Caitlyn!

8-Dale

79

I have seen one walk either! Except in Half Life… and I don’t think that counts as they didn’t obey gravity.

But, it won’t matter, as I will try to make it work anyway :smiley:

And yes, those are 11.1V, and yes that would fry any servo. I plan on using some 6V BECs.

80

Hi Sienna!

Exciting project you got there. Actually I have been playing (just thinking…) with a similar project like yours project but my idea was to hook two tripods together with 4 powerful servos using SES brackets… Almost like a monster mini Brat with two tripod feet :laughing:

But making your tripod walk… thats a real challenge!

Good luck and keep up your creative work! 8)