I’m thinking of getting a Hexbot, and being an ex-BattleTech gamer, I’m leaning toward the LynxMotion T-Hex chassis, with either 3DoF or 4DoF. But I have a few questions…
For non-combat uses, that’s just walking the wee beastie about, do I really need the 4DoF?
Do I need the more expensive HiTec 645MG servos, or could I get by with a cheaper model (at 18 servos for a 3DoF, for every $5 less expensive, that’s $90 total savings!
I’m thinking of adding ball-mounted footpads that free-float, so I ~think~ 3DoF would be enough. Yes-No?
If I change my mind on 3DoF vs 4DoF, can I convert a 3DoF T-Hex into a 4DoF by adding the appropriate leg sections at a later date?
Is buying the parts separately sometimes cheaper? Aka T-Hex chassis, then 18x servos, then controller boards… etc…
And how much more difficult is it to get the beastie running from a R/C transmitter than a PS2 unit?
I priced the 3DoF & 4DoF kits out, and how come the “3DoF kit” is $1261.11 (www.robotshop.ca) but if bought as parts, its only $994.78?
The SSC-32 is $44.38, the BotBoarduino is $83.21, 18x HS-645MG’s are $594.90, and T-Hex 3DoF chassis is $316.67. How does $994.78 become $1261.11 when purchased together as RB-Lyn-732?
Worth it for the 645 servos, I initially bought some 475 servos, wish I hadn’t. But I can only buy so much at at a time. Yes, you can update the legs by adding the additional parts. I just converted four 4DOF legs down to 3DOF for an inline BH3 'bot.
Isn’t the BotBoarduino in LM:
Model Number: BBU-01
Price: $34.95
And the SSC-32
Model Number: SSC-32
Price: $39.95
I didn’t price everything, but you might price them out on LM. Servos could be a little cheaper elsewhere as well.
Thanks for the other board links in yer siggy, Alan, I’m going to look about for assistance once I secure some hardware and begin tweaking it.
Agree on the legs… looks like the 3-to-4 DOF shift is just another leg section with servo and holder, then hooking it to the relevant spoot on the SSC-32 (looks like a sweet bit of tech, with that onscreen interface - watched the vid)
And yea… can always get the cheaper ones and possibly damage 'em, then sell 'em off to the R/C crowd if they are ‘insufficient for task’, as one might put it in a report.
And got a lead on a Hex, just gotta secure it in my mind, and then in my wallet…
Thoughts on the footpad idea? Saw a few of Halvorsen’s (aka Zenta) vids on YouTube and he had pads on a few of his bots. Even if the footpads freefloat or are marginally sprung to stay close to level/centered, they might give a better rough-terrain travel, yes?
My T-Hex does have the foot switches that Kåre and Jim (Robot Dude) did back then. These switches work a lot better than some of the previous switch setups. It has been awhile since I have tried doing anything with them.
My later TA stuff, I was spending more of my time playing with the Orion Robots and the Phantom Phoenix, where you can get feedback from the servos. So in theory when the leg is going down you can detect how much force it is asserting, to detect if it has hit the ground. if I remember correctly Kåre did some experiments with the PhantomX robot, where he told the servos of the legs going down to not use too much force as a way of stopping when it ran into something. From his video back then it looked like it worked pretty well. I keep meaning to try this.
Wondered if you had the Phoenix Mark 1 or 2. I saw the vid Kåre did of the Mk1 walking outside, and then at the end, ~flipping~ the beastie like a cat, and watching it re-orient its legs! That was amazing, as well as the speed it could move in the other vids, kinda creepy (reminded me of the ones in the movie " Runaway " with Tom Selleck.
I see there ~seems~ to be a Phoenix Mk.1 hex up on the trade area… decent price too, if its still available and he’ll ship to Canada… opinions vs the T-Hex?
OH… And is there a way to see which extra leg parts I need to make a 3DoF into a 4DoF? I ~think I can see by comparing the finished legs… there appears to be an extra section/assembly as seen in this image: lynxmotion.com/images/assemb … ssm05b.jpg (then again, the assembly count seems to say “NO”…) Anyone?
And Robotshop did reply to my query about the prices…" Thank you for bringing this to our attention. We will make the necessary verifications and update the pricing shortly. " Lets watch and see how long it takes 'em to fix the discrepancy, eh?
3DoF into a 4DoF? I don’t think the question has come up before. I think you could just look at the pix and instructions. I think I just unbolted about three parts, plus the servo, of course.
ASB04 multi-purpose servo bracket
ASB-11 angled C bracket
ASB-06 L bracket
I think you give up a long L bracket. At least I had to buy some to complete my 3DOF legs.
Guess I’ll put the query to RobotShop staffers, seeing as they replied to my pricing query so fast, and they OWN Lynxmotion now… they should make a 3DoF to 4DoF kit for that unit…
~IF~ Alan’s assessment is correct, this is the tally:
Net cost for 2 legs = $34.22, total for 6 legs (net cost x3) = $102.66 (I list no hardware cost as apparently it comes with respective brackets, as shown on the www.robotshop.ca pages)
Whatever I discover - whether they answer me with parts-list or not, say ‘duh’, or I manage it myself - I’ll post the answer ~if/when~ I get it, and also put it in a separate thread so others can find it.
As for the servos, strongly suggest 645MGs for their durability and torque.
Currently there is no upgrade kit, so you’d need (comparing the 3Dof leg with the 4Dof leg): ] 6 x 12" servo extender cables/:m] ] 3 x Aluminum Multi-Purpose Servo Bracket Two Pack (Black) (ASB-04)/:m] ] 3 x Aluminum “L” Connector Bracket Two Pack (Black) (ASB-06)/:m] ] 3 x Aluminum Offset Servo Bracket with Ball Bearings Two Pack (Black) (ASB-11)/:m] ] 6 x Servos (preferably Hitec 645MGs)/:m]
Looks like I got the “upgrade” kit right. Humm, my wiring is a little tight, some servo extenders may be in order…
I’d suggest listing the parts of any build included in the assembly instructions. This allows one to build an assembly piece-meal, rather then buying the entire kit at one time. Makes them easier to afford (some of us have wives). Of course having “leg kits” helps there.
Looks right. I did it mostly from memory, and the still-assembled parts I pulled off my 4DOF legs. It can be daunting to figure out the parts used in an assembly via the pictures (and I’m an engineer). After a while, you get comfortable with the fine parts. Watch out for the mirror-image assemblies. Also watch out for the bearings; It’s all planned out quite nicely, but if you build some of the parts, like a chassis, or maybe a set of tibias, then you won’t have enough.
I don’t know how many times I re-assembled a leg. Of course, I’m usually doing a couple of things at once. And a small TV in the shop doesn’t help…
Here I was gonna congratulate Alan for getting it right, and P{ost Cole’s confirmation, and you’ve all taken yer bows… mope
Right, would need the servo lead extenders and 6 more servos, of course.
Well, I need to get that package hewre fiorst, then liquidate the surplus to fund the extras I need/want, like mebbe a basic turret assembly, for a watercannon or perhaps BB-gun from one of the HenLong tanks (its a pitiful unit, but can be tweaked to be halfway decent…)
WhiteWolf
and I agree, a ~full~ parts inventory with set-by-step usage would be nice. I’d almost be willing to go thru the Lynxmotion T-Hex manuals and list 'em, if he would like to have assistance. (and letting 'em be downloaded as PDF’s would be GREAT!)
I like PDF files! I have an old Adobe Acrobat, and I can generate PDF files from a web page. Then I can file them in a directory with all the documentation I can assemble for a particular project.
Just lucky I hadn’t taken the assemblies from the leg change apart, so I could examine them. I did use two of the “kits” to build two additional legs.
I don’t know that they actually “need” a kit for this conversion, just an addendum onto the assembly instructions as what parts are needed. All the leg assembly guides could be annotated with a parts list. that would make it easier.
I would like to see a list of the leg types and their drawings, A,B, C and of course the T-Hex legs. And dimensions! (although I can get that my self of course).
I’m presently drawing up and dimensioning the BH3 chassis in my CAD/CAM program, Then I can dimension the X,Y,Z offsets for the inline 'bot. That should make it easier to re-do the [BODY DIMENSIONS] table. The axes and their signs are not intuitive. Somewhere I have a drawing of the proper axis orientation.
Had no sooner unpacked the beast Tuesday nite but I felt crappy, so decided to play with it later. Well, later is gonna be mebbe Monday, as I woke up Wednesday morn with a fever of 40c+. When that happens, its usually a central line infection, so I " got my *ss to hospital " (not Marz!)
Another bug in my bloodstream, so more antibiotics and mebbe a line replacement.
Will be begging more assistance on getting my wee beast from just standing there to walking, so get yer manuals out guys!
WhiteWolf & T-Hex (1st ed., brushed silver, not black)
PS: And then woke up Friday AM to find central line IV slipping out! Now docs got another reason to replace it… sigh
