litchralee

joined 1 year ago
[–] litchralee 0 points 7 hours ago

This is correct, although it may be for good reason: data for non-rider ebike injuries and deaths is not collected through the existing means, which focus mostly on motor vehicle collisions. The NHTSA's 2022 data report has this note:

Prior to 2022, motorized bicycles were collected as motor vehicles and classified as motorcycles in FARS and CRSS, and their operators and passengers were captured as motorists. Beginning in 2022, FARS and CRSS are no longer collecting motorized bicycles as motor vehicles. Consequently, operators and passengers of motorized bicycles will be captured as pedalcyclists when involved in a motor vehicle traffic crash. Any traffic crash involving only motorized bicycle(s) will no longer be captured in FARS or CRSS.

Essentially, the national data sources available today don't record bicycle-vs-bicycle or bicycle-vs-pedestrian injuries or fatalities. Some states or municipalities might record that data though. For example: NYC's 2021 data shows 2 pedestrian deaths from a bicycle collision, and 123 pedestrian deaths from a motor vehicle collision. But no data there on nonfatal pedestrian injuries caused by bicyclists.

A study looking at just a handful of municipalities would not be useful to draw larger conclusions. But seeing as the data collection at the national level was expressly designed to give insight into the most pressing injuries/fatalities category -- those involving motor vehicles -- I'm not holding by breath for expanded data collection, since bicycle-involves pedestrian collisions are at least an order of magnitude less of a problem than motor vehicle collision.

[–] litchralee 22 points 22 hours ago* (last edited 22 hours ago)

I like ebikes, but I lean towards the comments promoting plain ol bicycles as the optimal option. Simply put, a bicycle's only requirement is a reasonably-flat surface. If nature had provided roads, it's entirely possible for evolution to have devised wheeled creatures. For the same energy consumption, a human moves roughly four times faster or farther on a bicycle. That's a lot of advantage for zero extra energy.

But getting back to objective requirements, the other thing working in the bicycle's favor is the sheer number of them today: over one billion across the entire Earth, with around 100 million produced per year. If a world calamity happened right now and society collapsed, the estimated 60 million horses would become a luxury, not a utility, where 8 billion people vie for resources.

Obviously, much like a game of Catan, the horses and bicycles of the world are not evenly distributed. So if you're going to acquire something solely to put in the bunker for a doomsday scenario, I'd suggest not putting a horse in there; they won't like the dark.

[–] litchralee 4 points 23 hours ago

Horses, however, have high "emissions", in a manner of speaking. :)

 

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[–] litchralee 1 points 2 days ago (1 children)

That's wonderful that children are interested in the project. This and related projects would be great to showcase at Open Sauce. I certainly enjoyed this year's displays.

[–] litchralee 1 points 2 days ago* (last edited 2 days ago) (3 children)

I'm not an expert with building battery packs, but I think solder isn't a problem for connecting the nickel strips, so long as it's only a fraction of the whole pack. And if it's encased within the battery housing, spall won't be as bad of a problem. The highest currents would be where the "strings" are aggregated together in parallel, and that's usually when heavy gauge copper is used.

I recall that Aging Wheels has done videos on cell replacement, and I think maybe there was some sort of copper/brass busbar which aggregated the various nickel strips and then had large screw-down terminations for attaching external cables.

Rewatching your video again, do I understand that your emergency cut-off is inline with the full battery voltage? If your design had a smaller auxiliary 12v battery for powering the electronics, you could have a low-voltage control signal that closes a normally-open contactor that connects the main battery. Your emergency cut-off would be in-series of the control signal, so that loss of the signal immediately cuts off main battery voltage.

The same signal wire could be routed around to other safety sensors to isolate the main battery if something is wrong. In the most extreme case, the wire could be routed so that severe structural damage would automatically sever the wire.

This would also reduce the amount of heavy wire to only where it's needed, with some weight savings. Air conditioner condensers do this same trick, so that the safety sensors don't have to be rated for full 240 VAC.

[–] litchralee 3 points 2 days ago (5 children)

Nice build video! I'm also a sucker for a funny unit conversion from meters/metres to burger units. And wood- and metal-working, batteries, speed controllers, motors, micromobility, and beer? Instant subscribed.

You mentioned crimping versus soldering, and I'm poised to agree, especially in a mobile application with vibrations. Although I wanted to mention another reason for crimping: in the event of an unfused, high-current short, there may be sufficient energy from the cells to instantly vaporize the solder, causing hot spall to fly everywhere, potentially combusting flammable material. For this same reason, ham radio towers will always crimp their grounding conductors in case of a lightning strike.

Have you considered cross-posting to [email protected] ? Also, did you have a booth at Open Sauce?

[–] litchralee -1 points 2 days ago* (last edited 2 days ago)

All valid points, especially on sizing of kids bikes. For e-scooters, though, I'm not aware of there being substantially different sizes. If most public e-scooter program have only one size yet still works for a broad range of riders, then apparently fitment isn't as big of a concern than on bikes.

This YT video by OhTheUrbanity describes the cost differences between using a public e-scooter rental for general mobility versus buying a private e-scooter outright, with rentals being more expensive. They also observed at the time -- it's a 3 year old video -- that e-scooters can be purchased for CAD$800 or less. I think that's around USD$600, and other basic models can be had for less nowadays.

Given this calculus, it seems plausible that even for households with constrained disposable income, an e-scooter wouldn't necessarily be an extravagance and would not quickly be grown out of for a child. I personally don't use e-scooters, but I can see why parents might consider a cheap 15 mph (25 kph) e-scooter and helmet for their child, in spite of the injury statistics, if the alternative is having to drive them around, costing gasoline and a free-range upbringing.

 

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[–] litchralee 3 points 2 days ago (2 children)

I can't speak to the proportion of minors on acoustic bikes versus ebikes, but there are definitely under-18s with ebikes, in numbers ranging from "noticeable" to "common", if I may draw from anecdotes in my area and reports from around the country.

[–] litchralee 3 points 3 days ago (4 children)

This is a good point about data availability, and is certainly a caveat with the study. That said, I personally think legislation needs to be data driven, and when there's a lack of available data about a given topic, the absolute wrong answer is for politicians to gesticulate wildly and give into whatever moral panic happens to be sweeping through the constituency.

It's for this reason that I find that bills limiting minors on ebikes to be particularly pernicious.

 

The median age of injured conventional bicycle riders was 30 (IQR, 13-53) years vs 39 (IQR, 25-55) years for e-bicyclists (P < .001). Scooter riders had a median age of 11 (IQR, 7-24) years at the time of injury vs 30 (IQR, 20-45) years for e-scooter riders (P < .001) (Table 1 and Figure 3). As a group, those injured from EV accidents were significantly older than those injured from conventional vehicles (age, 31 vs 27 years; P < .001) (eTable 1 in Supplement 1).

e-Bicycles have lowered barriers to cycling for older adults, a group at risk for physical inactivity.9,10 Biking has clear-cut physical and cognitive health benefits for older adults, so this extension of biking accessibility to older e-bicyclists should be considered a boon of the new technology.22,23 However, as injured e-bicycle riders are older than conventional bicyclists, the unique safety considerations for older cyclists should be a focus of ongoing study.

There is a popular conception that ebikes are ridden recklessly on streets and sidewalks by youths, doing dangerous stunts, riding against traffic, not wearing helmets, and incurring serious injury to themselves and others as a result. This conception is often used to justify legislation to restrict or ban ebike use by minors. However, the data suggests quite the opposite, as it is older riders which are racking up injuries.

The data does not support restrictions on ebikes, but rather their wholesale adoption, especially for audiences which are at risk of inactivity or disadvantaged by a lack of transportation options. Ebikes are not at odds with conventional bicycles.

The California Bicycle Coalition offers this succinct summary:

“We think this backlash against e-bikes is the wrong direction for what we want for safer ways for people biking and sharing the road,” said Jared Sanchez, the policy director for the California Bicycle Coalition. “We don’t believe that adding restrictions for people riding e-bikes is the solution.”

They also have a page on how to fight against "bikelash", aka naysayers of bicycles and bikes: https://www.calbike.org/talking-back-to-bikelash/

[–] litchralee 2 points 5 days ago

This harkens to a Half As Interesting video (YT or Nebula) about trains being robbed at a very particular point in Southern California, between the port and the regional rail yard.

 

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[–] litchralee 7 points 1 week ago (1 children)

Not the Roman Empire. :)

[–] litchralee 0 points 1 week ago* (last edited 1 week ago)

Looking at the diagram, I don't see any issue with the network topology. And the power arrangement also shouldn't be a problem, unless you require the camera/DVR setup to persist during a power cut.

In that scenario, you would have to provide UPS power to all of: the PoE switch, the L3 switch, and the NVR. But if you don't have such a requirement, then I don't see a problem here.

Also, I hope you're doing well now.

 

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7
submitted 3 weeks ago* (last edited 3 weeks ago) by litchralee to c/kayaking
 

I have no prior kayaking experience except occasionally paddling one while camping with friends on still water. That's fun and all, but I'd like to get out on the water on my own, to some of the nearby lakes near me, maybe once a month during the sunny seasons. None of these would have anything remotely considered as "rapids".

My main consideration is transporting a prospective kayak, as I greatly prefer biking rather than driving a car for distances within an hour of me, which includes two or three suitable bodies of water. While I have the capacity to store a conventional hard-shell kayak at home, I'm exploring a folding kayak, since this could go with me in a car for farther locations, on a bike for nearby waters, and even a bus. I feel the hassle of moving a 12 ft hard-shell kayak would discourage me from ever using it outright.

This specific model won't ship until October, which might be a bit late in the season, but it's on sale for $300 out the door, or $273 because of a 10% email coupon for keeping it in my cart for an hour.

I'm aware that this isn't anywhere comparable to conventional kayaks, certainly not in price, rough water handling, and maybe not even longevity. But at this particular juncture, and for that particular price point, I think I have a use-case that aligns well with a folding kayak, and if I do develop the itch for something even better, I can always upgrade later. I can accept that this might be a "kayak-shaped toy", but if it floats on water and moves, I would be happy to start with that.

To that end, my questions for this community are whether there are other comparable folding kayaks I should look at, or reasons I should or shouldn't proceed with this purchase in the coming days.

Any and all advice would be greatly appreciated!

Update: I've ordered it and hope to see how it turns out when it arrives in October

 

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cross-posted from: https://sh.itjust.works/post/22165919

This entry of mine will not match the customary craftsmanship found in this community, but seeing as this was formerly a pile of miscellaneous, warped scrap 2x4 segments recovered from old pallets, I think I've made a reasonable show of things.

This bench is for my homegym, designed to be stood upon, which is why there's a rubber mat inlaid on the surface, a leftover of the gym floor. My design criteria called for even the edge of the top surface to support weight, so the main "box" of the bench uses 2x4 segments mitered (badly) together at 45 degrees, held together with wood glue.

I then routed the inner edge to support a 1/2" plywood sheet, which is screwed into the box. And then the rubber mat is glued down to the sheet, so there are no visible screws.

Finally, the legs are also 2x4 segments, cut so the bench sits 43 cm (~17 inch) from the floor; this is only coincidentally similar to the IPF weightlifting bench standards. I used screws instead of glue, just in case the legs needed to be shortened later.

All edges were rounded over with a 1/2" bit, as the bench is expected to be picked up and moved frequently. And everything stained in cherry and clear-coated.

Some of the annoyances from using scrap included:

  • Stripping old paint off. Awful chemicals, awful scrubbing, awful disposal.
  • Sanding away twists along the 2x4 segments
  • Filling nail holes or arranging them so they don't draw attention
  • My lack of experience with clamping and gluing wood that's not dimensionally consistent

wood bench beside a leg press

If I were to do this again, I'd figure out a way to reduce the amount of routing needed for the inner edge, since I essentially removed 0.75 inch by 1.5 inch of material all around the edge. This took forever, and perhaps a CNC machine would have simplified things, in addition to squaring and planing the surfaces before mitering.

 

cross-posted from: https://sh.itjust.works/post/22165919

This entry of mine will not match the customary craftsmanship found in this community, but seeing as this was formerly a pile of miscellaneous, warped scrap 2x4 segments recovered from old pallets, I think I've made a reasonable show of things.

This bench is for my homegym, designed to be stood upon, which is why there's a rubber mat inlaid on the surface, a leftover of the gym floor. My design criteria called for even the edge of the top surface to support weight, so the main "box" of the bench uses 2x4 segments mitered (badly) together at 45 degrees, held together with wood glue.

I then routed the inner edge to support a 1/2" plywood sheet, which is screwed into the box. And then the rubber mat is glued down to the sheet, so there are no visible screws.

Finally, the legs are also 2x4 segments, cut so the bench sits 43 cm (~17 inch) from the floor; this is only coincidentally similar to the IPF weightlifting bench standards. I used screws instead of glue, just in case the legs needed to be shortened later.

All edges were rounded over with a 1/2" bit, as the bench is expected to be picked up and moved frequently. And everything stained in cherry and clear-coated.

Some of the annoyances from using scrap included:

  • Stripping old paint off. Awful chemicals, awful scrubbing, awful disposal.
  • Sanding away twists along the 2x4 segments
  • Filling nail holes or arranging them so they don't draw attention
  • My lack of experience with clamping and gluing wood that's not dimensionally consistent

wood bench beside a leg press

If I were to do this again, I'd figure out a way to reduce the amount of routing needed for the inner edge, since I essentially removed 0.75 inch by 1.5 inch of material all around the edge. This took forever, and perhaps a CNC machine would have simplified things, in addition to squaring and planing the surfaces before mitering.

76
submitted 1 month ago* (last edited 1 month ago) by litchralee to c/[email protected]
 

This entry of mine will not match the customary craftsmanship found in this community, but seeing as this was formerly a pile of miscellaneous, warped scrap 2x4 segments recovered from old pallets, I think I've made a reasonable show of things.

This bench is for my homegym, designed to be stood upon, which is why there's a rubber mat inlaid on the surface, a leftover of the gym floor. My design criteria called for even the edge of the top surface to support weight, so the main "box" of the bench uses 2x4 segments mitered (badly) together at 45 degrees, held together with wood glue.

I then routed the inner edge to support a 1/2" plywood sheet, which is screwed into the box. And then the rubber mat is glued down to the sheet, so there are no visible screws.

Finally, the legs are also 2x4 segments, cut so the bench sits 43 cm (~17 inch) from the floor; this is only coincidentally similar to the IPF weightlifting bench standards. I used screws instead of glue, just in case the legs needed to be shortened later.

All edges were rounded over with a 1/2" bit, as the bench is expected to be picked up and moved frequently. And everything stained in cherry and clear-coated.

Some of the annoyances from using scrap included:

  • Stripping old paint off. Awful chemicals, awful scrubbing, awful disposal.
  • Sanding away twists along the 2x4 segments
  • Filling nail holes or arranging them so they don't draw attention
  • My lack of experience with clamping and gluing wood that's not dimensionally consistent

wood bench beside a leg press

If I were to do this again, I'd figure out a way to reduce the amount of routing needed for the inner edge, since I essentially removed 0.75 inch by 1.5 inch of material all around the edge. This took forever, and perhaps a CNC machine would have simplified things, in addition to squaring and planing the surfaces before mitering.

 

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The idea for this strange combination of arm day and leg day came from realizing that my existing leg press and many commercial preacher curl benches both share a 45 degree angle. So in the interest of consolidating floor space, I decided to build a preacher curl bench attachment for my Force USA machine.

Just like with stripping down the machine to fit against a wall, the goal is to build something which is removable, if I wanted to restore the machine back to factory condition. Conveniently, at the top end of the machine, there are three 11/16 inch (17 mm) holes on each side, meant for resistance band pegs. Likewise, between the frame and the chrome running surface is approximately 1.5" (38 mm).

Thus, it made the most sense to cut pieces of 2x4 lumber (actual size: 1.5x3.5 inch) that will sit within the frame, secured by two snug-fitting 5/8 inch (16 mm) wood dowels going through the top-most band peg holes. These side-pieces are held captive by the dowels, although the pieces can still slide inward of the frame, falling away from the peg holes. They're also not really weight-bearing. But they do provide a foundation to build upon.

To form a sturdy and flat base, I then cut some scrap 3/4 inch (19 mm) board that spans the width of the frame, and screwed it down onto the side-pieces using Torx deck screws, notched to avoid protrusions on the frame's top surface. This makes the board weight-bearing, since it rests flat upon the frame; the side-pieces prevent the board from sliding down. And by fixing the width of the side-pieces, the pieces can no longer fall away from the peg holes.

close up of preacher curl attachment on the leg press

Finally, any preacher curl bench requires a pad. For this, I simply went online and found what existing machines used. Having had a good experience with the parts department at Body Solid for my functional trainer, I looked at their GPCA1 preacher curl station, whose detailed PDF schematics showed a pad that is 600 mm wide, which is perfect for my use!

After $40 + $20 shipping, the pad arrived and I was able to measure the exact distance between its two bottom mounting holes to drill through the board. Once again, Body Solid's documentation described the exact 5/16" wide, 1" long bolts that I would need to mount the pad.

The final result isn't my nicest wood project -- to the point that I just stained it (badly) in black -- but it may have been one of the cheapest so far, using nearly entirely scrap materials except for the pad itself and the bolts. It also wasn't terribly complex and didn't require fairly high precision, unlike the short barbell project.

The whole premise of this attachment is that as an average height American (5 ft 9 inch; 175 cm), my range of motion for the leg press and hack squat simply won't ever push the carriage into the upper part of the frame. So it's free real estate.

preacher curl pad attached to the top of a 45 degree leg press

But wait: how am I going to use this? The pad is 5.5 ft (167 cm) above the floor. I'd have to be over 7 ft tall (2.2 m) to drape my arms over it. The answer to that will be its own future post.

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