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1. ## Thread: Walking Sequence for MK-III Hexapod?

by jwatte
Replies
6
Views
208

### Question(s)Re: Walking Sequence for MK-III Hexapod?

Ah! The button testing doesn't return values "greater than five" like the stick does.
Instead, you should test for "is not zero" because the buttons field is a bit mask:

if ((command.buttons &...
2. ## Thread: Walking Sequence for MK-III Hexapod?

by jwatte
Replies
6
Views
208

### Question(s)Re: Walking Sequence for MK-III Hexapod?

Then you can adjust it to read from the "button" input to decode where to walk, instead of the "stick" input....
3. ## Thread: 4 Dof Hexapod Torque calculations

by jwatte
Replies
1
Views
107

### Question(s)Re: 4 Dof Hexapod Torque calculations

Each joint can be individually calculated as if all the other joints are stiff, so I get pretty close by measuring the distance to the base points and the center of mass / weight of the body between...
4. ## Thread: New Member - Interested in retrofitting an industrial robot for hobby

by jwatte
Replies
10
Views
450

### Question(s)Re: New Member - Interested in retrofitting an industrial robot for hobby

The ROS platform uses the ODE library I think (Open Dynamics Engine) which is open source.

The bastards!
5. ## Thread: double eagle AEGs out of stock?

by jwatte
Replies
3
Views
222

### Re: double eagle AEGs out of stock?

I think the gun that the double eagle is based on is pretty old in the airsoft scene by now. Like most consumer markets, that market seems to work on trends and new products ...

Many gearboxes...
6. ## Thread: New Member - Interested in retrofitting an industrial robot for hobby

by jwatte
Replies
10
Views
450

### Question(s)Re: New Member - Interested in retrofitting an industrial robot for hobby

No, I mean run the calculations on the fly! You can use the simulation software to come up with a solution, and then back-calculate what the actual angles of actuation are by reading out the state of...
7. ## Thread: New Member - Interested in retrofitting an industrial robot for hobby

by jwatte
Replies
10
Views
450

### Question(s)Re: New Member - Interested in retrofitting an industrial robot for hobby

This guy is building his own 6DOF arm, mainly using 3D printing: https://www.youtube.com/watch?v=oFCUw1pXlnA
He's using steppers in this series, but he has a newer series where he uses the ODrive...
8. ## Thread: Absolute zero position for Dynamixel XM430-W350-R: How to change it?

by jwatte
Replies
2
Views
288

### Question(s)Re: Absolute zero position for Dynamixel XM430-W350-R: How to change it?

The documentation for Dynamixel protocol 2 (used by the XM430) talks about this. There is, for example, a "multi turn" mode. Or you can turn on "wheel mode," move forward, and then turn back on...

by jwatte
Replies
64
Views
11,529

### Re: The task (lawn mower topic)

... radars, railguns, electric arc based armor, ...

:-D
10. ## Thread: Hexapod for a beginner

by jwatte
Replies
11
Views
1,496

### Re: Hexapod for a beginner

The OpenCM 9.04-C needs an adapter cable, or the board, because it doesn't have the right connector.
The 9.04-A lets you solder in the connectors yourself, so you can buy the right connectors from...
11. ## Thread: Hexapod for a beginner

by jwatte
Replies
11
Views
1,496

### Re: Hexapod for a beginner

Looks like a good list!

If you use the "-T" servos, you don't need the 485 expansion board. You can get the "A" variant of the OpenCM and solder in the right headers yourself, I think. At least,...
12. ## Thread: Kodomoroid from up close

by jwatte
Replies
0
Views
297

### Kodomoroid from up close

I had the opportunity to see the Kodomoroid up close in person today.
It's creepy, as almost all human-emulation faces are. But they're getting closer!

https://youtu.be/X3FOLFj0nHE
13. ## Thread: Hexapod for a beginner

by jwatte
Replies
11
Views
1,496

### Re: Hexapod for a beginner

The XL430 is fine! It's the new raplcement for AX-12, and as you say, it has some upgrades.
I don't think Trossen has any hexapod kits for the XL430 yet, but if you're making your own, that's not a...
14. ## Thread: Maker Faire 2019 Mech Warfare

by jwatte
Replies
21
Views
2,597

### Re: Maker Faire 2019 Mech Warfare

Who needs working legs, amirite? :-)

These videos are great. Looking at them, I (Malum) clearly need:
1) a less-jammy gun
2) a bumper guard for my plates
3) more piloting practice

And maybe,...
15. ## Thread: FPV + HD Recording Options

by jwatte
Replies
2
Views
471

### Re: FPV + HD Recording Options

I'm rocking the AKK Infinite DVR now: https://amzn.to/2XVR2dY
It has SmartAudio, which I think will be necessary for configuring 'mechs to avoid interference.
16. ## Thread: Hexapod for a beginner

by jwatte
Replies
11
Views
1,496

### Re: Hexapod for a beginner

Budget RC hobby servos will be a throw-away cost if you actually end up wanting to build a real thing.
My recommendation would be to go for the AX-12 servos at the very least (i e, a PhantomX)
The...

by jwatte
Replies
64
Views
11,529

### Re: The task (lawn mower topic)

That's not too bad. Although 190 F *is* hot enough to congeal an egg ... but not hot enough to destroy most linear ICs like a regulator (typically rated to 150C or so for junction temperature.)
18. ## Thread: Novel leg/chassis design

by jwatte
Replies
10
Views
966

### Re: Novel leg/chassis design

And of course, my first-ever walking robot. A biped with only three servos!

(Actually, second-ever -- I built a smaller version in plywood with...
19. ## Thread: Novel leg/chassis design

by jwatte
Replies
10
Views
966

### Re: Novel leg/chassis design

I like the solenoid idea! You only need to activate it while the foot is "up" and presumably there would be a spring pushing it down with just enough force to keep it extended against half of the...
20. ## Thread: Novel leg/chassis design

by jwatte
Replies
10
Views
966

### Re: Novel leg/chassis design

Given that linkage, you should be able to move the feet in X/Y, but you also need something that changes which foot has most pressure (i e, lifting a foot.)
21. ## Thread: Novel leg/chassis design

by jwatte
Replies
10
Views
966

### Re: Novel leg/chassis design

I'm not seeing a picture?

Some contestants have used mechanical advantage. There was a nice two-legged robot a while back that used four servos total (two per leg, for "extent" and "front/back"...
22. ## Thread: Maker Faire 2019 Mech Warfare (WMFNY in Queens on Sept 21 and 22)

by jwatte
Replies
9
Views
1,519

### Re: Maker Faire 2019 Mech Warfare (WMFNY in Queens on Sept 21 and 22)

Oh, that's disappointing :-(
Thanks for the note!

by jwatte
Replies
64
Views
11,529

### Re: The task (lawn mower topic)

I know the feeling!

WHY ... CAN'T ... THINGS ... STAY ... WORKING !?!?!?

by jwatte
Replies
8
Views
981

### Re: Budget Class

There's typically one event in a year :-)
(Except for R-team, which has an Arizona Garage League)

by jwatte
Replies
8
Views
981

### Re: Budget Class

Realistically, those "simpler classes" exist for cars/planes/quadcopters because the technology and market adoption of the "main" classes has gotten to the point where that makes sense.
Walking...
26. ## Thread: Power for eight (8) Dynamixel XM-430-W350-R

by jwatte
Replies
6
Views
750

### Re: Power for eight (8) Dynamixel XM-430-W350-R

That should, theoretically, work fine! RS-485 is supposed to work across isolated ground domains (that being one of the main points.)

by jwatte
Replies
8
Views
981

### Re: Budget Class

I think the general idea is that the "cam driven" and "statically stable" designs are not in the spirit of Battletech-inspired warfare robots.
E g, the whole POINT is that it's not easy.
28. ## Thread: Power for eight (8) Dynamixel XM-430-W350-R

by jwatte
Replies
6
Views
750

### Re: Power for eight (8) Dynamixel XM-430-W350-R

I agree -- LiFePO4 are nicer in many ways (including number of lifecycles, matching to 12V rail voltages, and fire safety.)
Unfortunately they seem even harder to come by now than a few years back....
29. ## Thread: Power for eight (8) Dynamixel XM-430-W350-R

by jwatte
Replies
6
Views
750

### Re: Power for eight (8) Dynamixel XM-430-W350-R

The Robotis wiring is generally 22 or 20 gauge. 15A through a single 22 gauge wire will heat the wire to the point where the insulation will scorch, even if it's high quality silicone insulation. Or...
30. ## Thread: Camera for Arbotix-M?

by jwatte
Replies
3
Views
752

### Question(s)Re: Camera for Arbotix-M?

If you want a camera streaming to a cell phone, get a GoPro with built-in streaming/wifi support.
31. ## Thread: Supply robot with 8 MX-64T Dynamixels and measure power

by jwatte
Replies
1
Views
494

### Re: Supply robot with 8 MX-64T Dynamixels and measure power

You can run the MX-64 with 4S LiPo if you either don't charge the LiPo fully, or use a fat diode in line (to drop out a few tenths of a Volt -- gotta be rated for 8A or more on average, though) or if...
32. ## Thread: Pololu's Wixel + Arbotix Commander V2

by jwatte
Replies
7
Views
8,121

### ProjectRe: Pololu's Wixel + Arbotix Commander V2

I tried doing exactly this (with a slightly different OLED) with an Arbotix Commander and a PhantomX quad, but the Xbee turn-around time latency made the Phantom way too jerky in its control. (I've...
33. ## Thread: Maker Faire 2019 Mech Warfare (WMFNY in Queens on Sept 21 and 22)

by jwatte
Replies
9
Views
1,519

### Re: Maker Faire 2019 Mech Warfare (WMFNY in Queens on Sept 21 and 22)

I'm hoping to be able to come. (Need to get serious about finishing my gun!)

Btw, I find that the "edit the top post" mode of update is good for "what is the latest status" but bad for "what...
34. ## Thread: Maker Faire 2019 Mech Warfare

by jwatte
Replies
21
Views
2,597

### Re: Maker Faire 2019 Mech Warfare

All those GoPros gave you some pretty good angles!

by jwatte
Replies
64
Views
11,529

### Re: The task (lawn mower topic)

That sounds pretty good!

by jwatte
Replies
38
Views
6,351

My boss said her hair couldn't take a garage remodel right now, so re-pouring the pad is on hold.

However, given that I have neither a sine bar nor a set of angle blocks, I can kind-of squint and...

by jwatte
Replies
38
Views
6,351

@cire, that's a very good point! Thinking outside the box! I shall check with my boss, she probably doesn't need any retirement savings anyway!

by jwatte
Replies
64
Views
11,529

### Re: The task (lawn mower topic)

Many alternators have a regulator built in, and that regulator is, as far as I can tell, a linear regulator, meaning they sink a bunch of heat to the case when they would generate more voltage than...

by jwatte
Replies
64
Views
11,529

### Re: The task (lawn mower topic)

That's a fair bit of air :-D
At that point, the limiting factor may be the surface area of the alternator casing.
Which leads you to consider water channels, ....

by jwatte
Replies
38
Views
6,351