Intro:
I have had an interest in the leiftech and now Summerboard since I first saw it long ago. I was not however interested in paying that much to get one, so I decided to make my own.
My first real effort was to buy a broken Freebord and attempt to replicate the slip rings and motor mounts that the leiftech used. After a lot of research I saw that it wasn’t really feasible to do this. A great inspiration for me was this thread I came across as really the only DIY electric freebord out there. Very sadly never completed that we know of. (btw anyone know this dude?)
I cry thinking about the parts sitting in a bin somewhere possibly never run.
This brings us to the present.
Freebord MFG. launches a campaign to produce a new product line, the Freebord 5 and 5-X. I got excited since I had been sitting on this broken freebord for months not getting anything done, and this was exactly the kick I needed to get working on the project seriously once again. Being stalled on my ESK8 endeavors due to Covid-19 helped make me focus on it too.
A couple of things about the new models stood out to me as being useful for electrification. Both the caster bases being separate from the hanger baseplates, and the casters separating from the rotating base is great.
This gives you options to either remove the casters from the board entirely and replace them with some kind of powered caster like the one seen from VillainousJackal. Or you can take the small frame that holds the wheel off the pivoting caster base and bolt on your own version with a motor mount, and add a pancake slip ring around it somehow.
Modularity FTW!!
So here I am, Freebord pre order in hand, thinking about the simplest way to make this thing electric. I have very few manufacturing abilities, I barely have access to a working 3D printer basically all I have is a hand drill and a hacksaw (tools I think 95% of people have). So with the exception of a couple CNC/laser/plasma cut parts most of the design should be able to be assembled without a shop. I even berifly thought about making one of these electric broomsticks to mess around with but that would kinda suck.
The idea I settled on for now doesn’t seem very simple at first but I wanted it to be as independent from the rest of the freebord as possible so I could engineer it without actually having the board that I’m developing it for.
Background:
This design I have come up with is similar to something used in FRC robots called a “Swerve Drive” this would be a “Caster Swerve” due to the wheel offset from the rotational axis
I present: The E-Caster
older models:
Mechanics: Most of these parts are from Dickyho!
The whole design is built around a cheap 200mm lazy susan bearing. It isn’t very strong but I think it might be just good enough, and avoids either something really expensive or manufacturing my own. Hey if it’s able to support a whole table it could probably survive the weight put on it from some springs.
I’m still deciding what kind of motor set up I want to use. Having two motors obviously drives up cost significantly, requiring more ESCs belts pulleys and crap. It would allow me to use smaller diameter motors to achieve a lower profile and hopefully fit below the Freebord 5 and well as the 5-X as they have slightly different ride heights. The construction on the drive is very simple, using a 8mm shaft and a kegel wheel. Two bolts on kegel pulleys, one drilled out so the bolts slide through and into the other pulley. This could also easily be done with press fit pulleys, I’m not sure if you can put one in either side of a wheel but the pins could be shortened if not.
For the suspension aspect I need to put springs on it somewhere, for the moment I am thinking torsion springs because that would fit cleanly into the design but compression springs could be used instead and would match the look of the springs on the 5-X hanger arms.
I also really like this design:
single motor design with double sided motor axles inside the suspension arms as it looks sick but it has a couple issues as well, one being that the optimal choice of the APS 80100 50KV costs more than two of the small motors. It would require the belt drives to be outside the suspension arms, and also use a live axle with bearing press fit into the suspension arms (hard to manufacture and flanged bearings are expensive) instead of the dead axle. It could be possible to have a spacer that allows the motor to be center mounted and have the belt drives on the inside but it would be weak to 3D print and expensive to machine out of aluminum. Lastly it has the issue that if a rock or something gets kicked up it could jam between the motor and wheel. Still possible to pursue this design avenue, it looks much more clean and the motor would be protected. For now I’m going with the dual motors because it’s a balanced design and a great use for the Cheap Focer’s that I’m hoping to be having quite a few of.
Electronics:
Thanks for reading (or skimming?) So far! You hopefully noticed the giant hole in the deck, it would be needed to fit batteries on the E-Caster, but once you cut the hole, the sky’s the limit! (or at least your genital height)
It’s pretty darn simple due to not needing a slip ring, basically just esk8 electronics packed into a round shape. One thing I was thinking is that you have a reasonable but not too large battery like a 12S2P 21700, then stacked on top of that a swappable high capacity charge and ride module. Then riding could go on quite long! I think the battery consumption while sliding around would be quite extreme, even with a 350Wh pack I could see it going empty in like 5-7 miles. So the charge and ride packs would be fairly necessary, therefore making them easy to swap would be important. Given the footprint of the battery, 3D printing a battery + VESC enclosure would definity be possible so that is a plus for sure.
The total cost for this is fairly low, here is a guestamate
| Item | Price x Qty | Total |
|---|---|---|
| 200mm lazy susan bearing | $20 x1 | $20 |
| Aluminum and other shafts | Idk $60 | $60 |
| Motors 5065 | $36 x2 + $6 ship | $78 |
| Pulleys wheel/motor | $60 | $60 |
| Single Kegel wheel | $20 | $20 |
| 8mm Bushing ID 8x12x15 | $9 | $9 |
| VESC (cheapfocer2) | $69 x2 | $138 |
| 12S2P 30T + bms | $150 | $150 |
| totals | $570 ish |
What I’m interested in from you all in input on the general idea, good and bad. I’m hoping some of the great ESK8 parts manufacturers we have on here could help me find COTS parts that would make it more robust and still cheap and easy to make without a real shop.
This post is a work in progress, I’ll come back through and put more details about the current design where need be.
Thanks for the interest. Create and Skate on everyone.
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