What can you make with only three servos?

Lynxmotion Servo Erector Set
21

thanks! :smiley: this is so cool, now I cant wait for next summer to build my next SES robot :smiling_imp: but sadly I think I am going to buy a tracked vehicel with my money. But its sure I am going to continue with the SES, this shows that I have some skills in the robot field… :smiley:

22

Here’s another robot which, as far as I can tell, uses only three servos: it’s called the RB300, from JR Robotics and VStone. Looks to me like it can walk (OK, waddle) forwards and backwards, turn, stand on one leg and kick, and a few other things like bow or bend over backwards. I don’t know if it can stand up from lying down — I suspect not, but it’s still pretty cool. Their gallery includes some good pictures and videos; you really need to watch the videos to see how it works. (I found this via a RoboSavvy forum thread.) And one of the neat things is, much like the SES, most of the parts in this kit can be reused for the larger RB-2000 humanoid.

I wonder if you could make something like this with the SES?

Cheers,

  • Joe
23

I cant get some of the videos to work. some of the big bot and all of the small. i have all the things nessary I think. does this happen to anyone else?

24

Not me — using Windows Media Player 9.0 on Mac OS X, if that matters. But I’ll try to describe the action for you:

The two side servos, obviously, swing the feet forward and backward. The third servo horn is on the front, attached to that big front plate with the arms. It’s mounted near the bottom of this plate, so that it can swing it side to side. Take a careful look at the feet in the photos, and you can see that they are not flat; they are slightly tilted, and have a foot pad along the inner edge. This means that the robot is bistable: it can tip just a little bit to stand on one foot or the other, and whatever foot it’s not standing on then clears the ground.

So, to walk, it swings its front plate over to one side, which tips it onto that foot, and then moves its feet forward/back appropriately. Then it swings the front plate the other way to shift its weight onto the other foot. The robot body as a whole doesn’t actually waddle very much, but the front plate and arms gyrate pretty far. But that’s good for duking it out with another robot (which the videos show).

Also, upon watching the videos again, I noticed that it actually can get up from falling over, at least on its front. I suspect it can do so from its back too, thanks to that protruding bit of frame back there, which otherwise serves no purpose I can guess. If it lands on its side, I don’t know… but maybe it could swing its front plate enough to tip it over onto its front or back, then proceed from there.

All in all, it’s a pretty clever design, and I can see learning a lot from it (or something like it) without investing a fortune. But I don’t know whether it really requires special brackets, or whether something similar could be made with SES parts.

Best,
— Joe

25

wow! thats cool!

I think you cant its not like the SES and you cant take it apart, or build up from that smaller one. but it is cool clever design, but it cant be done with the SES I think, but you could you own brackets. the feet for the SES are much to big, so if it swing on one side, it will not be able to advance its foot since it will it the floor. but it cool that it can get up, with only 3 servos! but I hink for a longer project, the SES would be more fun, since you can do almost all the robots you want.

26

That’s an impressive biped! It looks like it uses a total of only 9 servos; 3 for each leg, one for each arm and one for the head.

I bet you can make this with the SES brackets. It would be a cheap way to build a biped to go along with the BRAT.

My favorite video was the solo drummer.

27

the small robot only uses 3 servo, one for each leg and one to move the metal plate in the front (where the arms are put) anyway, that what I saw.

28

Thanks for this! I think I’ve found a small error though. The parts list at the top specifies an EC-01 electronics carrier, but what’s shown in the assembly guide appears to be an EC-02. (In fact, upon closer inspection, the EC-01 link actually goes to the EC-02 page, so it looks like a simple typo.)

Best,

  • Joe
29

Error? Typo? You speak such harsh words. :laughing: If you refresh the page, you’ll notice that everything is correct. :wink:

30

Oops — I daren’t say it, but I seem to have found other… shall we say… discrepancies. :wink: But I’m new to this, so maybe I’m just misunderstanding.

In Step 1, the text calls for using 2-56 x .125" screws. But the figure directly below the text shows 2-56 x .188" counter-sunk machine screws.

I’m assuming that the ones shown in the text are preferred, to give a flatter sole and to avoid sticking up too much into where the servo should go. Is that right?

Thanks,
— Joe

P.S. I received my first order today, and will soon be building one of these things (albiet with custom feet and electronics carrier). I’m very excited! :smiley:

31

Cool!! I want to see it! bring some pics and videos, it would be cool!! By the way is yours in black oor silver?

Sam

32

If you’re like me, you’ll get a rush when you see your first robot actually move under its own power and control. :smiley:

8-Dale

33

Black, the One True Color for aluminum robots. :slight_smile: I’ll certainly post some pics and videos when I have it up and waddling.

Best,
— Joe

34

It’s a minor typo. We’ll fix it.

35

It’s fixed. Enjoy.
lynxmotion.com/images/html/build112.htm

36

Thanks! I’m assuming you want to hear about it when an error is found in the instructions… but if there is a more preferred way to report errors, I’ll be happy to use that instead. (Maybe a “report an error” link at the bottom of each instruction page would help?)

Best,
– Joe

37

Yes, I do appreciate having typographical mishaps reported, and it doesn’t really matter how you do it. The forum works fine, or you could send me an email: [email protected]. Either way, I’ll get it and fix it. :wink: