Let's Make Robots!

Making of LadyBugBot clone

[See updates and videos on the bottom of this page]

Isotope's LadyBugBot looked like fun to make so I thought to give it a try. Also, this bot would make a great gift to someone having a kitchen renovated and I just happen to know one :-)

The body of the bot is made of (otherwise useless) CD or DVD disc and Papier mache. I have never done anything with papier mache so first thing I did was creating some "body tryouts" (actually I did that about 2 weeks ago).

First I tried using some bowls as a mold. Because I still wanted to use my bowls for food I protected them with plastic wrap.
papier-mache-bowl.jpg

After a couple of hours of work and a few hours of drying this is how it came out:
papier-mache-from-bowl.jpg

Pretty good but they are a little "flat" and a bit too big for a CD. Next I tried to use balloons as molds. To make them easier to handle I used adhesive tape to attach them to small bowls. This is how it looked like:
papier-mache-balloons.jpg

And this is how it looked like after the first layer of paper:
papier-mache-balloons-1st-layer.jpg

I noticed that paper on the balloons was drying very quickly and I had to sprinkle water on other balloons while I was working on one. It would have been easier to work on just one balloon at a time. After a couple more layers (4 or 5 total if I remember correctly) it was time to let them dry. They look quite nice:
papier-mache-from-balloons.jpg

My electronics orders arrived last week and I've been busy playing with my new toys. And because I orders parts for three different bots I have a lot of new toys ;-)  One funny thing was Speakjet chip. It's not going to be used on my LadyBugBot clone (it would be cool though) but I just had to try it out. Here's a video of it working: http://www.youtube.com/watch?v=EtJZCr83POM
I used droidbuilder's schematic to build the circuit for Speakjet.

Ok. Back to LadyBugBot clone. The original used continuously rotating servos but I though I'll try to use motors. So I had to this to have enough free output pins on Picaxe 08M:
tristate_l293d-2motors-schema-upd.png

That's circuit to drive to motors using only two input/output pins on 08M. I wrote a tip about it earlier here.

Oh. I almost forgot. Magnets :-) I ordered some neodymium magnets from supermagnete.de. Those magnet are strong I tell you :-) Here's a picture of magnet testing:
magnet-test.jpg

There's three magnets with 3,4kg pull force each holding two Solarbotics GM3 motors and four AA NiMH cells. Those three magnets are so strong that I think GM3 motors don't have enough torque to move the bot :-D Here's a link to those magnets.

By the way, 216 small magnetic spheres are really fun to play with (they have nothing to do with the bot, just for fun):
216-magnets.jpg

Currently I'm making yet another papier mache body for my bot. The smallest one I made earlier using balloons quite good but it was just a bit too small. With some fixing it might fit but just because papier mache is so fun I decided to make a new one. This time I created a "wire frame" model first (I used the "balloon" model to help shaping the wire frame model):
wire-frame-model.jpg

I have already done 4 layers on the wire frame. It has been drying about an hour and a half now so I think it's time to get back to work and make a couple more layers. Here's how it looks like now:
wire-frame-model-first-layers.jpg

 

 



Update Feb 27 2010:
[Added link to magnets above and some new pictures below]

 

At first I thought that I'll go the easy way and do just one body part and do "the shell" part (or elytra as wikipedia says) just by painting it. Then I realized that because this is going to be a gift it must have easily replaceable batteries. So now I'm going to try to make some kind of mechanism to allow opening of "the shell" part. So far I have only thought of using a simple hinge but other ideas are welcome.

I promised new pictures so here they are: First "the shell" part. I just marked the edge of the shell using red tape and wrapped the previously done part in plastic wrap. Then it was time to add some papier mache. Here's how it looks like after drying:
with-shell-part-after-drying-1.jpg

Here's those two parts separated:
with-shell-part-after-drying-2.jpg

And parts with the wire frame model (hey it's reusable):
with-shell-part-after-drying-3.jpg

I'm quite satisfied with the result. Next thing for the body is to do some cutting and painting and to figure out the opening mechanism for the shell part.

I forgot to post pictures of the wheels earlier so I'll just put them right here. I'm going to use Solarbotics GM Wheels but they don't offer much traction so I need some tires. I remembered seeing some rubber bottle caps and now that I think of it: they do look a lot like tires, don't they:
bottlecap-tyres-1.jpg

Those bottle caps have 27mm inner diameter so they fit nicely to 30mm wheels. After some cutting I had a pair of nice wheels with rubber tires:
bottlecap-tyres-2.jpg

I added a small amount of glue between wheels and tires to hold tires in place.

So this is it so far. Getting closer to finishing the bot. I just have to figure out the opening mechanism and then it's more or less just painting and putting things together.


Update Mar 5 2010:

Just finished a vertical test run. There's an embedded video of it or you can watch it here. It's not running on a fridge but on a water heater. It's working quite well already and there's only one magnet holding it.

Too bad I'm not having enough time to work on the bot. It's taking ages to get it finished.

On a side note: Spray paint wasn't a good idea. At least the idea of painting the body black first, then adding "tape spots" to cover those black spots and finally over painting with red. It said on the can that you can paint over after 15 mins but maybe I did something wrong. The result is ugly!

 

 


Update Mar 8 2010:

 

Getting there. Slowly. I finally got all the electronics in place and shot a new video of my LBB clone running on a table. I also tried different kind of paint (paintbrush kind of paint) and the result is looking much better than previously (with spray paint). See the pictures below.

Spray paint looked just **** ugly (and weird in the photo):
ugly-spraypaint.jpg'

After the epic fail with spray paint I tried paintbrush and the result is looking much better:
after-paintbrush-painting.jpg

Even though the result was quite good after the first layer of paint I decided to add another layer. For some reason there's now a kind of wavy texture on the paint. I don't know why. It didn't look like that after the first layer. One reason might be that the paint dried too quickly because I placed those painted parts on bathroom floor and that floor has heating (that is on only during night time and that's when the paint was drying). Anyway the wavy texture doesn't bother me too much to I'll just let it be. Here's a close up where you can see the texture:
wavy-paint-texture.jpg

And finally here's a couple of close ups of a modified micro switch acting as a bump/cavity switch:
bumb-cavity-switch-01.jpg

bumb-cavity-switch-02.jpg

Now I just have to find time to finish the painting and do the final assembly. (And hope it will still work.)

 

 



Update Mar 12 2010:

 

OK. Now I'm feeling like I'm teasing people but I just had to post one more picture before finishing this one. Here's a picture of the body with finished paint (and eyes):
lbb-clone-painted-body.jpg

It's looking quite cute if you ask me :-)

So close... So close now... Hopefully I'll get this one finished this weekend. I think I got the opening mechanism figured out too. It's not going to be as cool as I originally wanted though (red parts of the "shell" opening "independently"). Maybe in the next version then.

 


Update Mar 21 2010:

Well... My bot has been ready for about a week now but I have been busy so robot page had to wait. I've been playing with the bot myself every now and then though. Today I thought that I'll finish the software, shoot a video and write a robot page. Guess what happened...

I rewrote the SW, tried it a few times on my desk and then decided to shoot the video of the bot running on the fridge door. I put the bot in place and powered it up. The bot runs just fine for awhile and then... My bot committed a suicide!

It ran too close (or a bit over) the upper edge of the fridge and because the edge is plastic and it was in a such angle that my bump/cavity switch didn't detect it and it's a bit higher than the door itself my bot fell on the floor. The DVD disc cracked to pieces where I had glued the hinge so I have to build the whole thing on a new disc. Luckily nothing else got broken. On the bright side: Now I can (try to) put the tires a bit better in their place.

Check the last video if you want to see what happened.

 

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That's nice! :))) Good idea to use baloons! When I read that you are going to use motors instead of servos, I was going to warn you about gravity, as motors are way heavier than miniature servos, but then I saw your magnet test pics... Man, those magnets you've got are beasts :)))) Looking forward to see more of it! Good luck, and keep us posted!

Balloons were really good molds. The smallest one came out almost perfectly round.

Those magnets I used for testing are maybe too strong. At least using three of them. I'll probably use just one (maybe  2) and a couple of smaller ones to balance the bot.

I also noticed that with newspaper to make papier mache you get "smoother" surface than using 80g/m^2 copy paper. It feels like you could do quite small details with it.

 

I love the laydbeetle fridge robot...

After some thinking about using using the tri-states on 08M pins  nuumio, I've simply pulled out a couple of barely-functioning (very) cheap servos and pulled off the control board inside, and attahced them to the motors directly - so now I can control two 3v motors as if they were servos - giving full control over the motors with on pin each AND saving on space because I don't need that ugly great L239D chip in there. Anyhow, just a thought - if space is an issue in this case, you can spend about the same as a L239D chip on a couple of cheap servos, gut them to get the control board... 

It's not cheating, it's optimising!

If your friends are ok with using a skrewdriver, you can use same mechanism I used: hot glue 4 meccano L pieces with 1 hole to CD base. Drill through body and use 4 skrews to hold body on cd base.
I used spray to paint body and tried to do spots same way, and, yes, it was ugly! I had to paint over body again :(  I ended up using black nail laquer to paint spots, and the result you can see on photoes :D

That was scary sound there! I thought it all broke to pieces :) The bot looks cute btw! :D Nice work! Hope to see robot page after you do some surgery to it!

The surgery is going on right now. I just glued motors to a new disc and now I'm adding magnet. The old disc broke to pieces but the "shell part" didn't get any damage. Looks like papier mache is quite tough material :-)