NickReiser's Biped

Let's Make Robots Projects Showcase
21

That’s just about what I did (only a transistor instead of the bumper) and it’s proving to be adequete but not great. The problem is the high friction between the foot and the leg. You can pull the foot snuggly on the leg and the sensor will read a constant non-zero value. You step once, raise the foot and it sees a drastically different value. After stepping 50 times, it doesn’t seem to settle down. That makes interpreting the data quite tough, and my bot is now quite heavy. It will be much hard on the lighter ones.

I could see it working more reliably sandwiched between two hubs that somehow have an ever so slight, but consistent amount of play between them. Locktite the nuts just shy of tight? Not pretty, but I think that something along those lines mechanically would be ideal.

22

we’re hijacking this thread… I’ll continue my new findings over in the ground contact sensors thread.

23

Okeydokes, I’m back.

I did more puttering, but not anything that really helped.

Yes, there are four FSR’s there.

I’ll solder it all together a really crappy solder – nice to have, when you want a temporary hold – after dinner, just in case they’re not making good contact.

I haven’t done any penny stackin’ tests, yet, as that little test block didn’t allow for much mobility.

I’ll get back to you guys in handful of hours with the results.

24

Ok, after a ton of testing, I got everything functioning properly.
I had to use my voltometer to test VA and VB because the LynxTerm’s VA and VB display a very shakey and confusing voltage (probably the SSC-32’s fault).

I have to say, this circuit is really nice, and so are the Phidgets FSR’s.

I can push down on them as hard as I can (has to be more than 250 lbs of pressure) and they’re not damaged in the slightest.

In this circuit, the time between my pushing and releasing of the FSR’s as hard as I could (pushing until VA read 0.29V) and VA returning to 4.94V was too instantaneous to be noticed.

I was able to notice the resistance change from 0 back to 30.0+ kohms (no connection) when I measured it across an extra FSR’s terminals.
But, I think that was my meter being slow, and not the FSR.

If anyone wants me to do any tests with these, I’ll be happy to (provided that they don’t entail destroying them, or me, hehe).

I’m off to go build my biped (parts just arived!).
Don’t expect to see my pretty face for a while.
:smiling_imp:

25

After two full days of working on the biped non-stop (well, I ate a couple of meals :smiley:) I’m pretty much finished.

The annodized humanoid looks KILLER.
All black and shiny silver, so pretty…

On a scale of one to ten, ten being the highest, the new biped is a 10^99.
Twelve thumbs up, Jim!

I’ll post a picture once I figure out how to get the SSC-32 and BotBoard mounted onto it’s back.
(I routed the wires to the back, but it still looks messy w/out anything to attatch them to.)

Speaking of that…
Jim, can you post a pic of the back of your biped prototype?
I know that you said that the way you mounted it was only temporary, but temporary is all that I need right now.

^.^

26

Pictures Nick… Where are the pictures!?

LEt me see your awsome project!

27

Yeah, what he said_ _ _ ^ :laughing:
especially since I plan on doing mine in all black also. Can’t wait to see it!

Tinman

28

:smiley: Hang in there, guys.
I lied about posting them last night.
I forgot that I’d have to go coach rec track.

I should be done with mounting the electronics by lunchtime, so I’ll post the pics after that.

Trust me, it’s worth the wait (so pretty!).

:smiley:

29

It’s 5:05 here in Houston Texas, how long of a lunch are you taking Nick?
:laughing:

30

Hehe.

Actually, I didn’t take lunch at all, today; I was too busy.

I had everything all built and ready to program for the standing position when I found that my lovely SSC-32 didn’t work.

I had the LED lit up and the servos holding their positions fine, and everything seemed right…
And, after ten hours of ripping my hair out measuring things that I had no right to measure with my voltometer, I found the problem.

I had removed the two jumpers that set the baud rate to 15200 so that I could plug in my Bot Board.

.<

So… that lunch deadline kinda got lost.

I just finished lunch and banged together a couple of pics for you guys.
They don’t really do him justice, but they’ll have to do, for now.

x11.putfile.com/3/7219200216-thumb.jpg

In the second pic, you can see how I mounted the electronics.

x11.putfile.com/3/7219233294-thumb.jpg

I don’t recommend doing it the way that I did it, as the gap between them won’t fit the head servo, and it also won’t fit the large battery (and it’s too big for one 9V).

I’ll be banging (I like that word) out a new one in a few weeks that will either fit the head servo in there or at least the battery.

Currently, I don’t have a micro for my bot, but I have all the other junk that I need.
I’m waiting until I get a handle of programming the WiPort >>> SSC-32 before I throw another brain into the mix.
I might not even put in a micro if I can get by without it.

31

DUDE!! THAT IS SOOO AWESOME! (in my best surfer/slacker voice)

In all seriousness, Nick that bot looks great. 8)
I am really impressed with the black brackets. Very slick.

I do not know if it would be possible but maybe you could turn the boards 180 degrees. would that help with the head mounting?
Just a thought.

very nice can’t wait to see him in action.

Tinman

32

Nick,

Very nice, indeed. Where did you get those cable wraps you used to cover the servo wires with?

Mike

33

It looks like you painted the wires, is the left hand something you fabricated?

Tinman

34

Those wires are painted with a plastic spraypaint.

I definitely don’t suggest doing it.
It worked great for a bit, but now it’s pealing off in a gucky mess.

I patched the mess up with a bit o’ black permanent marker for the photo shoot.

I’ll be replacing all of the servo leads with my own flat sensor wire leads once I order the pin crimps that I’ll need to do that.

(That way, each lead is exactly as long as I need it to be.)

The left hand is made from half of the two lexan brackets that make up one of the Biped Scout’s thighs.
The battering ram end of it is four steel hex standoffs attatched with two ASB-12 (skinny “L” brackets).
I had a bunch of extra parts from the Scout kit lying around, so I figured that I’d chop some up and put 'em to use.

(By the way, I DO recommend painting the lexan with a plastic spraypaint, as that doesn’t peal off or become gucky; in fact, it’s pretty hard to scratch off.
Just be sure that you abraid the surface first.)

If you look closely, you’ll notice that the right hand isn’t stock, either.
I bought the regular robot hand and attatched two steel dowels to it with a bunch of Erector Set (the non-Lynxmotion Erector Set, that is) parts.

I’m happy to say that all of the banged-together hand pieces are not in the least bit wobbly.
In fact, they’re much stronger than the original hand (probably because I put a lot more bolts through them).

I’ve been troubleshooting the WiPort all yesterday and today, but I’m giving it up for a while so that I can get this guy walking.

I’ll post back with a vid when I do get that done.
(Sometime today or tomorrow).

35

Now those are some nice images! That bot has Ati-Tude! Can’t wait to see it in action. Wish I had more time to play! :frowning:

Well done Nick! Well done!

36

Bravo! Two thumbs up! Outstanding!

Well done Nick!

As for the video, I won’t except anaything less than 15 minutes @ high res!

JK, I can’t wait!

By the way, where did you get those aluminum servo horns? I can’t find them anywhere on the Lynxmotion website.

37

Those were a gift from Jim.

(Thanks, again, Jim!)

Apparently, his fabricator messed up and bored them smooth to accept the small, black, phillips bolts instead of keying them.

So, Jim sent me the incorrectly-made ones for free!
It was a real hastle trying to bolt them on, though, as it was near impossible to put them on the servo and then bolt a bracket on.

After I realized that I could just bolt the bracket to the servo horn first and then just flex the “C” brackets a bit to get them over the servo, it went a lot faster.
I wouldn’t recommend that method for the plastic servo heads, as it’s very possible to strip the spur cut into the back of them.
This isn’t an issue with aluminum ones, though.
^.^

They were definitely worth the initial hassle, though.
So pretty!
I would expect to see the correct versions on the site quite soon.

Update on my progress:
Not much, been hopping between getting the WiPort up and running and setting the stop values for the servos and tweeking the servo’s mechanical placements.
So, I’m not getting much of either done.
Hopefully, I’ll finish the servo preparations tonight.

By the way, changing the mechanical placements of the servos is much easier with the new horns.
Instead of taking everything appart, I can just unscrew the single servo screw in the center, flex appart the “C” bracket, turn the servo, and stick it back together.

Speaking of getting back together… I better get back together with my biped…
(Who’s name is Midget, btw. For those of you who’ve seen “Nightmare” on my site, I found that to be too corny.)

38

Well, the WiPort still isn’t up and running.

I actually got it working late last night, but the battery died (I hate Murphy’s Law), and I couldn’t get the Ad-Hoc connection going after that.

I did manage to finish setting the servo offsets, today.

That’s a bit time consuming, but once done, I was able to knock together my “Home” position and my “Gonna Kill 'Em” position in less than 10 minutes.

The Visual Sequencer is soooooooooooo much easier to use than the terminal program.
It’s very intuitive, and I’ve never needed to look at the online directions (which is a first!).

Anyhow, here’s some pics that do Midget a bit more justice:

Crouching Robot, Hidden Biped

x11.putfile.com/3/7418570928-thumb.jpg

Kapow!

x11.putfile.com/3/7419044221-thumb.jpg

Union Break
x11.putfile.com/3/7419104554-thumb.jpg

Boy, he sure is a slacker.
:smiley:

39

Well Nick it looks like you found a temporary fix for where to put the batteries!

What sort of snags did you run into with the Wiport, as that is what I intend to use as well.
You will have to give us a review on the sequencer, I would be very interested to hear how it is working out. User friendly as described?

Cool photos!
Tinman

40

Very user friendly.
The first thing that you do is turn it on and adjust your servo endpoints.
(You do this so that your servos don’t try to move farther than the brackets allow them to.)

After that initail hassle (which isn’t difficult, just annoying, because you want to get to the good stuff), it’s all downhill.

You open the sequencer part of the program, build your robot in whatever way makes sense to you.
And, then you adjust the sliders, save the position, adjust them a bit more, save that one, yadda yadda yadda.
And then you play the whole sequence.

I really like how the playing is set up.
You have individual positions which are saved within a sequence, then multiple sequences get saved into a program.

It makes it very easy to program complex behaviors.
Instead of having to make each sequence, you can copy ones that you’ve already banged out and move them into a new part of the program.

I also like how there’s little markers on the sliders that show where your last position was, so you don’t have to remember where it was.

Overall Rating: A+

Well, the snags that I’ve run into with the WiPort have all been software-related.
I actually just got it running again last night (odd, it seems to like to cooperate at night) by changing a few network settings around.

It’s talking to my computer, now, and I’ve assigned it a static IP address (so it doesn’t have to search for a free one every time it’s reset).
But I haven’t been able to get it to assign itself to a COM port properly, yet, which will enable me to get rid of the serial cable —> SSC-32 that I use now.

I’ve been pestering David (dgarske, on these forums) and he’s been a great help.
I’ll let you all know exactly how I got it working, once I actually get it working.
If I told you now, it would be very convoluted, and filled with a lot of unecessary tasks.

About the batteries, yea I managed to stuff one in a bit crooked.
:stuck_out_tongue:
I thought it looked rather dashing for the photo, as it sort of looks like a head.

I’m going to try to ignore the WiPort for today, and get my lil’ bugger walking around.