Sienna's Random Robot Thread!

Yay! I am finally starting on my robots… (Ignoring the small ones I did in college and then kinda left collecting dust :blush:)

For the near future, I plan to have two robots: A tank, and a hexapod. The tank is going to be called “Big Brother”, and the hex “Little Sister” (if you haven’t guessed yet, the hex is going to be a LM Phoenix). I call them like that because I eventually want an the hex to be able to ride on top of / inside / etc the tank for long range travel.

(we won’t get into the maybe more disconcerting messages associated with my desire to put a computer inside the tank, and have it control the hex via wireless… 8))

“Big Brother” TODO list:
Initial Order from LM for tread, sprockets, motors: Done.
Order from BC Laserworks for Initial design of tread section: In work.
Order from McMaster for roller chain, sprockets, nylon: Waiting for Paycheck :stuck_out_tongue:
Order from Digikey for 2.5" standoffs: Waiting for Paycheck
Order from Dimension Engineering for BEC, Sabertooth: Done (a little out of order…)
Order #2 from LM for misc stuff to connect to undesigned middle section… not on the charts yet.

In short, based on the long range of parts that are still needing to be ordered, I have some ways to go yet before I actually have a robot…

As far as the design of “Big Brother” goes, I plan on doing the tank in three “modules”… two of the modules will be identical, and be just the tread sections (so, the LM tank tread, sprockets, idlers, roller chain, etc). These now have an initial design, shown here:
(this is just the design for the laser cutter… imagine two of them holding the idlers on each side, and standoffs with nylon around them in the small holes on the edge.)
(sorry for the big picture!)

The middle section, well, thats going to be a bit while it is being designed.

Sounds like a sophisticated project, how long do you think its gonna take you and cost you to make? My goal is similar except i want a quadropod to hang onto the back of my boe bot or possibly a humanoid in the near future. Well good luck :smiley:

Very cool sounding project. I think you were the one helping me out in the other thread, so you probably know that I have something similar. I ordered the roller sprockets you suggested from McMaster, and I hope you don’t mind me stealing your idea for mounting them :blush: (hopefully I won’t need a keyway, and if I do it can be done with a dremel)

Have you decided what you want to use for motors? I ordered two 350W scooter motors (MY1016) from a scooter parts site for like $30/each. I plan to control them with an OSMC (they draw 19.2A no load, probably 90-100 at stall)

I’m interested in seeing how your project progresses.

A while, and a lot of money :stuck_out_tongue:
Actually, I estimate this robot would cost about $800 or so all told, but I haven’t done the math. Of course, its also a bit bigger then anything stock from LM. (I seem to be physically not able to start with something small!)

Isn’t a Boe Bot quite small? How do you hang a quad off the back of that?

Absolutely not!! Thats what the forums are all about!

For now I am going to use Jim’s PGHM-02s. I didn’t want a motor that drew that much current without a load, and stalling under 5A seems nice. We will see if they are powerful enough to move the bot. Also, I don’t have any power sources yet capable of supplying a big motor’s demand!

Sounds like a good project. Sounds like this tracked vehicle is a delivery system for an LM’s Phoenix…

Sounds like this project will keep you occupied for a while. BTW, we have similar sponsors, our pocket!

Well technically im still in the “Brainstorming” phase of my project but if anything i might make a small little mount on the back of the bot. Right now im planning on upgrading the con. servos to something more powerful and speedy (if you have any suggestions please tell me! :confused:)

And for the humanoid im still drawing schematics and then eventually moving into CAD modeling for the final draft.

Good luck with your project! :smiley:

Not trying to hijack this thread, but check out some of the examples on my humanoid biped with waist rotate thread for some suggestions. I borrowed many ideas from LM’s SES “what can I build” page and also from the various Kondo KHR-series bots…

Ok, back to the topic of Sienna’s project… :wink:

Sienna, you should be getting paid for that kind of advertisement :wink:

getting back on topic, I like the cutout for the tracks. My suggestion would be to get the sprockets connected to the motor off the ground. Add lots of idlers at the bottom (maybe some sponge tires for some supsension) —>

Also, might be a good idea to make the tracks go above the chassis if you plan on continuing the drive if flipped over :wink:

This setup has two LM sprocket pairs. One connected to the idler hub in each of the circles that the 18" dimension connects. They are approximately an inch or so off the ground IIRC.

This is only version 0.1… for a reason. This was my “fist step” to just build something “small” that works. In the future, by version 1.0 or so, it will probably be at least a foot tall and two to three feet long, and have the ability to climb stairs (at a minimum, that will be the design goal). In addition, the entire bottom of the chassis will be sprung with a lot of RC shocks, as well as having the front part of the chassis shock mounted as well (in case the code fails and it runs into something).

As far as the ‘current’ 0.1 design, the entire chassis in the middle of the bot is vertically between those two rows of four holes (designed to take Jim’s square aluminum stuff). The entire 0.1 design is being engineered with ‘flip over’ in mind.

:open_mouth: Wow thats one huge rover, it would be real cool to see a video of it climbing stairs :smiley: What kind of controller are you going to use for it?

For now, probably a basic atom pro or something.

In the future, an embedded mini, nano, or pico itx pc.

In other news…

Assembling 8 feet of track is a PITB… Of course, once I took out my hammer, it went a lot faster 8)

Now that I have the track together, and simulating the distance apart, I think I am off by about 0.5" (too long wheelbase)… :desk So, I will have to confirm just how bad I am off when I get the first run of my tread module walls. Barely got started, and already finding problems :smiley:

Well, I got my order from McMaster-Carr today. I ordered two of the sprockets that you suggested in the other thread. Fit seems to be pretty good with the two set screws, even though the bore is large by 0.01" I would post a picture for you if I could, since you gave me the idea and you don’t have yours just yet. It’s nice because the (sprocket) hub’s width actually seats the sprocket itself almost dead center within the LM hubs.

Hopefully the two set screws will be sufficient…

I’ve achieved similar results using my girlfriend instead of a hammer :smiley:

I would say the minimum you should go with is the Atom PRO - it’s faster and has more program memory, as well as more hardware features.

Do you do Linux at all? Linux would open up an entire new set of possibilities for embedded systems on a robot. I’m experimenting with a full Linux system on a single 40 pin DIP now. Of course I have a carrier board it rides on that has support circuitry, including two USB ports (both can be Host or Client).

This is part of the experience. I just got the set of new decks for W.A.L.T.E.R. but was off on hole spacing for the motor mount holes. I got everything else perfect in the design for all the decks though!:D:D Did you create CAD models all your custom parts? I modeled every deck, fit everything together, etc, before I sent DXF files off to Alan (KM6VV). I also have a 3D model of the hex standoff, with configurations that allow me to set it to different lengths I use.


Yep, I will use the Atom Pro… as that is what I had ordered from Jim to start with. I also have two I think OOPIC Mark III Boards, as well as some normal PIC Mark III boards. The only thing I don’t have is my Warp 13… thats lost somewhere.

I assume your 40 pin linux device is the Hammer? Let me know how it does!

I would do all my design in 3D if I could, but I don’t have a program at home that does assemblies. Alibre doesn’t run on my computer (vista 64). I really think I was making an assumption that the tracks were 24" long versus 23" long. Normally I have a very good spatial system in my head. In college I designed a multideck sonar housing array all in my head, and then in a 2D (yes, two dimensional) CAD package. When I got the parts back from the laser shop, I think there was only one minor thing wrong, everything else assembled quite nicely.

But in reality, making mistakes doesn’t bother me. I enjoy the building of the robot infinitely more then I do the programming (despite the fact that my major was in computer science). Jim has my dream job, build robots all day and get others to program them :smiley:

I do PIC/dsPIC stuff also. I use an Olimex ICD2 I bought from Spark Fun. It works great, programs all the chips I want to work with, and has never given me any grief. I need to get back to doing some PIC/dsPIC stuff.

Yes, it is a Hammer. I was fortunate enough to be able to get an evaluation kit (Full Hammer Kit). I have had it working with a 2 GB Thumb Drive. :slight_smile: You’ll see more about it in the Linux section and/or my W.A.L.T.E.R. thread in the Rovers section when I have it ready to go on W.A.L.T.E.R. :smiley: I am almost ready to interface Hammer to a couple dsPICs.

That sucks because Alibre Design is a very nice package. If you need some help with CAD modeling, just ask. :wink: I have even modeled my BRAT in 3D.

I am the opposite. I would much rather be working on the software for robots than actually building them in most cases. I have to admit though, when I started rebuilding W.A.L.T.E.R. with the new decks that I designed, I got a rush when all the holes (except motor mount holes) lined up perfectly. :smiley::smiley: I much prefer the design and programming aspects of robotics though. I build because I can’t avoid it.


So, why do you build it then? Surely there are a lot of people on the forum that would either build/design it for you, or kit it so you just have to program it?

Eep! I missed this post! Thats cool, I am glad it worked. I was thinking of offsetting my chain to be non-centered, so that on the drive side I could have two sprockets, one for each idler.

I hope you gave her a nice romantic dinner or something for that. If not, she and I need to consp… talk. :look

Caitlyn :smiling_imp:

:laughing: We go out all the time. Probably too often living on the budget of two college students. But she enjoys putting things together; she’s actually the one that asked me if she could help

The PGHM-02 is a good motor for small bots but i believe you are going to use 2 sets of tracks per side. I used the PGHM-03 and it moved my tank but uphill it was very very slow and sometimes couldn’t make it. I used some CHEAP cordless drill motors from they came with drill battery and charger. Only downside is its hard to make motor mounts for the drill motors.
I would also suggest the sabretooth 2x25 25 amps and 24 volt.
I tried the 2x5 and smoked it in less then 2 minutes with the cordless drill motors. Also with the drill motors the tracks did increase in length, had to add a tentioner to the tracks. Use locktite on all set screws also.
The flip over design is cool i tried that but with my metal body the RC was blocked unless the reciever was higher then the body (one dead reciever on that test :wink:)

Looks like you got a great start just some ideas so you don’t make the same mistakes i did and it cost you lots of extra money.

Actually, those drill motors I belive have threaded holes into the case. All you would have to do it screw them into the body. This has been done by a lot of people…including me :wink: