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xx2747
08-07-2009, 02:13 PM
Hello,
I've been trying to make a cheap humanoid (kind of impossible if I'm trying to make a nice one) but I'm going to try anyway.
So, I bought 8 of some cheap chinese servos with .16 sec speed and 14kg torque(I half-believe them) for 8 bucks each. If these work out it would be $64 well spent but if not... oh well. My fault that I even tried them.:happy:
Now I have to wait for that to come and school starts in roughly bout a month so I thought that I needed to test if the robot's future leg orientation would work well. So I made a miniature scaled leg with 4 servos with micro servos. (btw the robot's gonna have 4 dof in each leg)
The parts for the mini scale was made using a bandsaw and drill press. No brakes pr anything like that...

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these servos were attached together with scrap metal and servo tape (very effective)

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darkback2
08-07-2009, 02:24 PM
Hey,

Good Luck with this project...(not sarcastic...I actually mean it...good luck.) I gave this one a try about a year ago. What I ran into was two things...the cheap servos tend to burn out quickly, and while the torque ratings may be true, they come at the cost of accuracy. The cheap servos I've tried tend to "jitter".

Keep us posted, and let us know how it goes.

DB

Noodle
08-07-2009, 08:48 PM
Please Note: You get what you pay for. The best humanoids are uber expensive. A BRAT is cheap. Compare them as "humanoids". Good luck and keep us posted.

kanda
08-08-2009, 08:18 AM
Interesting topic, can't wait to see more :)
Where did you buy these chinese servos ? Ebay ? Hobbyking ? Other ?

xx2747
08-08-2009, 12:53 PM
here's a link.
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=2&Product_Name=HXT_10kg_Servo_(metal_gear)_55g_/_10kg_/_.16sec
P.S.- try at your own risk. hehe

xx2747
08-08-2009, 01:05 PM
OK
So I need a microcontroller to control this thing when it is built.
I was looking at the SSC-32 from lynxmotion to control the servos and make movements but it has to be tethered to the computer. Any suggestions of controllers that can control up to 12 servos and have sensor inputs? Also I have like no programming experience.:) a cheap one would be great as I have a tight budget.

jes1510
08-08-2009, 01:27 PM
Look at the Roboduino or Arduino family of microcontroller boards. If you pair one with and SSC32 then you wil have more than enough outputs and inputs to control this thing.

xx2747
08-08-2009, 01:53 PM
Are they hard to program? Or at leat learn?

Adrenalynn
08-08-2009, 03:19 PM
Yes. No. Maybe.

[BEGIN: Philosophical Statement]
"Hard to program" is an impossible to answer question unfortunately. How much programming experience do you have? If you don't know how to program, then you have to learn how to program before you can program. Then the question becomes not "how hard is it" but rather "how hard is it for you?"
[END: Philosophical Statement]

lnxfergy
08-09-2009, 12:01 AM
The Arduino has great online documentation, I'd suggest reading through some of the tutorials on http://www.arduino.cc , if it seems completely foreign and crazy to understand your answer is "yes", if it seems fairly manageable, then no.

Of course, beyond just the learning of a programming language, the other question would be how much do you have to learn about humanoids, walking, and the construction of a pose-based gait engine (or whatever gait engine it is you choose to use).

-Fergs

billyzelsnack
08-10-2009, 02:30 PM
I think you might find this link inspiring..

http://translate.google.com/translate?u=http://robot.watch.impress.co.jp/docs/news/20090810_308380.html%3Fref%3Drss&sl=ja&tl=en&hl=en&ie=UTF-8

billyzelsnack
08-10-2009, 02:47 PM
Looks like this is the servo from the spec page on vstone..

http://www.himodel.com/radios/12.5g_Digital_Ball_Bearing_Micro_Servo_DS-929MG.html

I wonder if metal gears and being digital are a requirements for decent operations on a bot like this because if they are not then the fantastic HXT900 servo has the same torque, but for $3.45 each.

http://hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=662&Product_Name=HXT900_9g_/_1.6kg_/_.12sec_Micro_Servo

billyzelsnack
08-10-2009, 03:06 PM
hmm.

http://74.125.95.132/translate_c?hl=en&ie=UTF-8&sl=ja&tl=en&u=http://www.vstone.co.jp/robot/robovienano/rspec.html&rurl=translate.google.com&usg=ALkJrhimoz316yxjTYqgp4FF6z4Qmxqy3Q

Says the DS-929MG, but on the first page I linked it says "Servomotor "VS-S020". The torque 2.2kg cm"

The VS-S020 makes more sense, but the DS- 929MG is listed on the vstone site.

xx2747
08-16-2009, 06:55 PM
hmm...
The link you said that was inspiring wouldn't open...
But, the new robovie looks very cool. Considering the price, 510 dollars, it's very cool!
I was looking at the GWS park servos with 4.8kg of torque and 0.08 sec. of speed.
I researched hard to find this servo... It's cheap too, and fast.

Anyway, the thing I hate the most of standard servos is the ears. The stupid things that jut out the sides. I use the 4 screws on the back side to attach it to things. This thing limits movement and makes the servo too long (or big).
The robovie servos seem to solve this problem.
Thanks for telling me about the new robot. Also, I have a few HXT900s right now. My dad uses them in park fliers(airplanes) and they look good.

xx2747
08-17-2009, 06:30 PM
ok
I received my servos today (total of 8) and I'm trying to figure out how to do the bottom axis since the servo doesn't have one. (I wish every servo had one like robonova's servos...) any suggestions?

Also, the the horns supplied by this servo isn't round which ticks me off. The hitec ones don't match and I'm stuck. The site where I bought the servos from don't mennntion it either. poo. :(

Adrenalynn
08-17-2009, 06:44 PM
>> any suggestions?

Look into the Lynxmotion SES brackets

lnxfergy
08-17-2009, 07:10 PM
>> any suggestions?

Look into the Lynxmotion SES brackets

Just FYI - If they are GWS servos, Lynx brackets may not work (since most GWS are oversized). Measure carefully.

-Fergs

Adrenalynn
08-17-2009, 07:28 PM
Good point.

darkback2
08-17-2009, 07:45 PM
Hey, You may have to roll your own on this one. If I remember correctly you have some way of drawing and cutting out brackets. A bandsaw, drill press, vice, and hammer are about all you need. You can pick up a pair of sheet metal pliers at any hardware store or home center, and a set of calipers, analog or digital, your pick will work fine. Given that your going for a humanoid precision is going to be hugely important. Its kind of like origami. A small mistake or variation at one point will have huge implications down the road.

You may be able to find round servo horns that fit your servos. If hitech servo horns don't fit, try futubas. In the end though you may have to settle on using the horns that came with your servos. There are a number of hobby shops on your side of the ferry. I've had luck with drilling a hole in the servo hinge that the horn can be pressed through, then bolting the long arm of the servo horn to the hinge arm.

All the best.

DB

xx2747
08-17-2009, 08:18 PM
Will they fit my servos?
I'm pretty sure they have different dimensions.
Also, I was looking for something I could make at home.

Adrenalynn
08-17-2009, 11:09 PM
You can certainly make brackets at home. When I can't get the right size, I make my own. As DB illustrated, it doesn't take more than $500-$1500 in tools plus the raw materials.

lnxfergy
08-17-2009, 11:32 PM
You can certainly make brackets at home. When I can't get the right size, I make my own. As DB illustrated, it doesn't take more than $500-$1500 in tools plus the raw materials.

$500-$1500??? I can accomplish quite a bit with a hacksaw, pair of pliers, and a cordless drill..... YMMV

-Fergs

xx2747
08-18-2009, 12:41 AM
well I have a bandsaw and a press and a vice and a hammer and all that but it all comes down to precision, in my opinion. The bends are the worst parts of making a bracket for me - I can never bend consistantly.

Anyway, precise or not, I went ahead and made a braket similar to the one from lynxmotion - the one that wraps around the servo to provide the other axis. The problem is, how do you attach a bracket onto the axis hole to make it spin? I've tried a nut and a bolt with a washer but they come loose.

I'll post pivtures later on to show what's going on.

Also, I've thought of a possible solution to my dislike of the servo ears - just break them off. It'll make everything so much easier...

jes1510
08-18-2009, 12:47 AM
If your load isn't huge then you can use a shelf pin. They are the plastic pins that hold shelves in book shelves. It's a piece of plastic in an L shape with a peg on the other side. Cut off the "L" and secure the plastic to the back of the servo with strong double sided tape. You can pick up the Shelf brackets at Lowes in the hardware department. I think they were just a couple of bucks for 2 in a bag. I've used this exact method before and it works great. Plus it's dirt cheap.

Adrenalynn
08-18-2009, 01:37 AM
Lynxmotion sells their bearings pretty cheaply too. http://www.lynxmotion.com/Product.aspx?productID=363&CategoryID=6

You can find similar elsewhere too.

xx2747
08-18-2009, 12:45 PM
How does the bearing attach to the brackets?
Lynxmotion doesn't have pictures.

lnxfergy
08-18-2009, 01:11 PM
How does the bearing attach to the brackets?
Lynxmotion doesn't have pictures.

http://www.lynxmotion.com/images/html/build083.htm

-Fergs

darkback2
08-18-2009, 01:59 PM
You may want to look at silicone spacers. You can use locking nuts to hold the screws in space if that is the problem.

DB

xx2747
08-18-2009, 04:05 PM
thanks everyone for the help.:happy:

Here are some pictures of the bracket and the servos

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The U shaped bracket attached to the servo one is just an example of the hinge system.

darkback2
08-18-2009, 09:41 PM
I know I have a twisted tendency to over engineer everything, but I'm thinking your servos may have a tendency to twist around and break off the little ears that hold them to the brackets if you aren't careful. Might be wrong on that though. In the least I would consider using some double sided tape to hold the bracket in place.

DB

xx2747
08-18-2009, 10:33 PM
Yes
Actually I was thinking of breaking the ears off on purpose and just using servo tape.(I think they'll hold on)
The ears just make everything difficult for me so...

xx2747
08-19-2009, 03:40 PM
Servos, say hello to Mr. Eartearer!

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This mean tool is a servo's worst nightmare - it tears their ears! (that's a nice rhyme)

It does a great job at it too: it makes very clean tears - like it never happened.

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I'm only going to rip off one ear per servo though.

ARGHH!!!

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Adrenalynn
08-19-2009, 04:11 PM
>> (that's a nice rhyme)

But only if they're crying instead of having their ears ripped off.

xx2747
08-19-2009, 05:28 PM
Yep.
I just noticed this too - Mr. Eartearer is like Mr. EarTerror. haha haha hah... sorry.

mannyr7
08-19-2009, 05:47 PM
I'm thinking the torque necessary to move and hold the weight of a biped will more than likely rip the servo from its mounting tape, but i genuinely hope that's not the case. In any case, there's always the ol' handy dandy zip tie! Good luck!

p.s. I've been thinking about making a PDF of my home made brackets in flat pattern. SES compatible, of course!

xx2747
08-21-2009, 09:45 PM
Hello,
Here's an update on the project.

I finished making the ankle braket that will be attached to the foot. I was very surprised at how precise it was. I'm very proud.:happy:
So, here are a few pictures of what I have so far. Oh, in the picture, everything is put together with just tape. (very useful when testing stuff) The final version will be with servo tape.

The axis is working fine - I settled on the locking nut-and-bolt method.

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The feet is a card - for now

nagmier
08-21-2009, 10:34 PM
Its good to see this project starting to take shape! You look like your doing pretty good with those brackets nice job!

xx2747
08-28-2009, 10:49 PM
ok
I have this so far...

The leg is pretty heavy since the servos are metal gears. I hope they'll hold the weight.

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darkback2
08-29-2009, 12:31 AM
Hey,

I really like how minimalist you are going with this. I'm sure the legs are heavy, but you may be able to get away with a shuffle gate instead of actually lifting the feet. If I remember correctly your only running 8 or so servos, so you may be able to get away with not having a torso and arms.

DB

xx2747
08-29-2009, 01:24 AM
Yes, I am only using 8 servos for the legs and possibly 4 for the arms.
Looking at this robot(the one in the video) with like 15 of these servos walking , I think I can manage to make it walk normally. After all, if the statements at the chinese website is true, it has 14 kgs of torque.

YouTube - Runbot's 1st prototype

Also, I directly tested these servos with a remote controller and it works well. The knee servo has no trouble lifting the rest of the leg. I'm (so far) satisfied with them.

Adrenalynn
08-29-2009, 03:49 AM
>> it has 14 kgs of torque

Don't forget that that is stall. At the axle. Not operating at the end of the lever.

xx2747
09-01-2009, 08:40 PM
Ahh...
I think there is going to be some delay in this project as school started for me today. :(
Now I have to homework everyday. poo. I didn't even get into the robotics class.

But on the bright side I have almost completed the left leg and made all the brackets for the right side.
I hope to finish the assembly of the robot before like October. (with the limited time I have in the weekends)

xx2747
09-07-2009, 02:11 PM
Finally kind of finished the right leg.

Some of the robot is put together by tape as of now but I think I'll make brackets for them later on.

The problem with this project is that it is very hard to attach brackets because there are no screws or holes for screws on the servo. The robot servos solve this problem but I have the servos with ears. Of coarse I can attach brackets using the ears but (in my opinion) that just makes the servo bigger and limits movement.

any suggestions regarding the attachments of brackets would be nice.:happy:

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bigderhak
09-07-2009, 02:30 PM
I like the magnetic security sticker :D.
Well it would have been easier if you did not remove the other ears but I have a few Ideas I'll try to draw them up.

xx2747
09-08-2009, 09:10 PM
Yeah...
The magnetic thing was just lying around on the table and I needed something solid to connect the servos so I put them there.

The diagrams would be nice too.:)

I heard(well, read) that you bought a bioloid kit recently. Congratulations!

bigderhak
09-08-2009, 10:45 PM
Yeah I can't wait to start making something with it. Bi, quad, hex.. who knows.
I did not find a free minute at work today to draw something up. I should be able to get to it tomorrow. Also if you just plan to keep this as it is you could epoxy the two housing together. 5-minute epoxy from devcon is a great all around epoxy (unless it is going to see H2O, it doesn't like water) or a cyanoacrylate (superglue) most should do. But I will still draw somethings up.

xx2747
09-11-2009, 12:27 AM
I'm thinking about buying a SSC-32 soon. Is this a decent board to start with and control motions on a easy level, or should I start with something else like a microcontroller so I can have my robot tether-free and thinking on its own?
Any suggestions on cheap controller boards?

Also, I have a choice of either buying the controller board or more servos, and I think ordering the servos and finishing the hardware part of the robot first would be better. :)

Adrenalynn
09-11-2009, 03:09 AM
The SSC-32 is a very full featured but simple to use controller. A microcontroller is going to be far less full-featured for servo control unless _you_ write the code. And then that's basically all it's going to do. It's pricepoint is unquestionably outstanding.

Personally, I slap an SSC-32 on anything that has more than a couple servos. Save my micro to perform more important tasks.

darkback2
09-11-2009, 07:42 AM
I would go with an SSC-32/xbee combo. I'm probably going to be switching squidword over to that soon. That way the bot can be PC based without the weight. Also look into the lynx motion sequencer. That way you can have pre-programmed gates. Connor did that for mechwarfare.

DB

xx2747
09-21-2009, 12:21 AM
Yes.
I am, going to buy the sequencer too.
I'm wondering what else I need to get my robot up and running besides the SSC-32, the software, the battery for the servos, and the battery for the board. I'm going to keep my robot tethered to the computer for now.

Also, I visited a plastic shop and bought several plastic sheets to expiriment with. I have aluminum frames now but I am going to replace them with plastic (probably polycarbonite) due to accuracy issues. Polycarbonite seems nice cause it's not that heavy and it's sturdy and flexible.

So approximately the electronics for the robot costs $100, the servos cost $70, and other parts roughly about $30.
That adds up to about $200 if I buy the electronics soon. (I'm guessing that's cheap compared to other bipeds and I'm aiming to get this thing built and moving for under $400 so I haven't failed yet)

sam
09-21-2009, 09:53 AM
Yes.
I am, going to buy the sequencer too.
I'm wondering what else I need to get my robot up and running besides the SSC-32, the software, the battery for the servos, and the battery for the board. I'm going to keep my robot tethered to the computer for now.

Well, that's pretty much everything you need to get started. I assume you have a RS-232 port (or a USB to serial cable) and the actual cable to connect it to your computer.




Also, I visited a plastic shop and bought several plastic sheets to expiriment with. I have aluminum frames now but I am going to replace them with plastic (probably polycarbonite) due to accuracy issues. Polycarbonite seems nice cause it's not that heavy and it's sturdy and flexible.

So approximately the electronics for the robot costs $100, the servos cost $70, and other parts roughly about $30.
That adds up to about $200 if I buy the electronics soon. (I'm guessing that's cheap compared to other bipeds and I'm aiming to get this thing built and moving for under $400 so I haven't failed yet)

Keep up the good work! Very low price for a humanoid, especially considering you bought the electronics.

Sam

xx2747
09-26-2009, 06:58 PM
Okay so...
The estimated arrival of my order from lynxmotion is monday.
I have made a couple of changes to the left leg of the robot just to expiriment with things: I attached polycarbonite frames and it looks cleaner than aluminum so I think I'm gonna stick with those. Also a major change, I didn't like the nut and locking bolt (too loose and hard to take apart) so I used a new and better method - the plastic and screw. I just added a 1/4 in. thick ABS sheet on the opposite side of the horn and put a screw in it. This proves to be more stable and easy to take apart.

Here are some pics. The right one is the new version and the left one is the old.

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xx2747
09-28-2009, 08:11 PM
Order from Lynxmotion received!

xx2747
10-04-2009, 12:26 AM
So I uploaded a short video of Cheapy on YouTube. (that's what I decided to name the robot cause, well, it's cheap!)
YouTube - Cheapy the Low-Cost Humanoid Robot
Any feedback or suggestion would be appreciated :)

mannyr7
10-04-2009, 12:54 AM
Very cool!!! Hoping you get both legs of this puppy walking soon!

sam
10-04-2009, 05:55 PM
Looks very nice! :eek:

That ankle looks really cool.

xx2747
10-04-2009, 06:56 PM
it seems like the cheap chinese servos are holding up. (not sure for how long though)
Also I was thinking over the frame materials again. Aluminum is light and durable but not as precise when it comes to bending them. Plastic is durable and cheap but a bit thicker and heavier than aluminum and is gluable (which means nice, clean 90 degree edges) and it looks cleaner on the robot. I don't know what to use. Maybe a combination of both would work?

xx2747
01-24-2010, 06:51 PM
YEAHHH!!!!

okay, so I've been busy with other stuff and everything that I had to set my Cheapy project aside for a while. And this weekend I decided to finish this darn thing once and for all...!

So in two days I built the right leg and now I have attached both legs on a plastic platform. It actually looks like a biped now!!!

yeah! sorry I'm just excited haha :tongue: but here are some pictures. Oh, BTW, the project has cost me about $300 so far. I mean, not bad for a biped right?

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Robert's got a new friend! (half a friend for now i guess:happy:)

Sigma X
01-29-2010, 08:09 PM
Looks like we're in the same boat I also have a cheap humanoid too i'll post pics soon