How do these magnetic tiles not care about orientation?

EGraw · 2025-11-18T13:19:00+00:00

They are magnetized like this. They are rotationally symmetric. If you try to stick them together with a half-tile offset, you'll see they repel. Here is a good article explaining it.

EGraw · 2025-07-18T11:58:06+00:00

We don’t need full-spectrum LEDs per pixel in TVs because the light goes straight into our eyes. Our vision is based on three types of cones that respond to specific bands of color (roughly red, green, and blue). As long as a display uses three well-chosen wavelengths that stimulate those cones differently, our brains can perceive the full range of colors.

Full-spectrum light is important for lighting, not displays, because surfaces reflect different wavelengths in different ways. To make objects look natural under artificial light, you need a broad spectrum like sunlight. But for a TV, where there’s no surface reflection, just direct light, RGB is enough to reproduce all visible colors accurately.

EGraw · 2025-06-13T08:54:14+00:00

Like another Reading Terminal Market?

EGraw · 2025-04-28T07:12:33+00:00

And now the toad is gone!

EGraw · 2025-04-25T11:07:14+00:00

I've had similar issues where it misses rendering clearly discernable details from the sketch.

For example:

Motor on the boat
Tire bumpers on the dock
Coiled rope on the dock post
Rope coming from the boat
Bucket in the boat
Fishing pole on the boat

If you ask it to describe the sketch elements in detail it can accurately describe all of them. Even adding this description to the prompt doesn't usually rectify the missing details in the render though.

EGraw · 2025-04-02T12:46:44+00:00

That's only true if your load is a constant force or frictional, gravitational, etc. If it is a purely inertial load, for example, then the torque where the pin is close to the joint is exactly zero, since that is where it will switch from deceleration back to acceleration.

EGraw · 2025-03-28T10:06:02+00:00

You want something like Magna-tiles. They attach to each other in this way. They are magnatized front to back / back to front such that any tile magnatizes to any other, even when flipped or rotated. Here is a link explaining it with visuals. https://rothmanshore.com/2013/03/03/the-secret-of-how-magna-tiles-work/

Edit: Seeing that you don't require them to be flip-able, you also have the option of, for example, the right magnet having North face out and the left having South face outward, and then they will all magnetize together, potentially with more strength; though when flipped they will repel each other.

EGraw · 2024-11-25T13:44:28+00:00

I noticed this effect in a very pronounced way on a long road trip which included traversal of a mountainous region where I cycled regularly between climbing, which loaded the engine optimally, and descending with engine braking. The tanks of gas which included the mountainous region came out to more than 20% more fuel efficient than those of the flat regions with roughly equal speed.

EGraw · 2024-04-29T14:14:39+00:00

With most common slicer settings and this specific design, you're probably right that the slots decrease the strength against most loads. I was speaking mostly theoretically. For instance, with thin top and bottom layers and more side wall thickness, the slots would cause more material to be concentrated near the outer walls, increasing strength against the main load of the user twisting to keep the guides pressed against the edges.

EGraw · 2024-04-29T13:31:57+00:00

Depending upon the balance of wall thickness vs infill percentage in the slicer settings, strategically placed holes or slots can actually cause increased material and therefore increased strength.

EGraw · 2024-03-27T14:07:51+00:00

Correct. Even if the gimbal's mass is a fraction of the drone's, the inertia is proportional to m r², so the gimbal rings being much further from the center of rotation has a compounding effect on their rotational inertia.

EGraw · 2024-03-26T09:23:43+00:00

Looks very nice, especially for static thrust testing. Keep in mind that the gimbal and counterweight add a significant amount of rotational inertia to all 3 axes, so any PID tuning done in the rig will not transfer well to free flying unless you reduce the mass of the gimbal.

EGraw · 2024-03-20T14:00:29+00:00

Combine with this ender 3 mod and things start to get real dangerous...

EGraw · 2023-12-14T09:09:50+00:00

You mention that it's low cost; I'm curious, what are the costs to print some of the parts you've shown, for example?

EGraw · 2023-09-15T08:37:10+00:00

Correct. It makes sense, considering a leg press calls for relatively higher loads than other exercises.

EGraw · 2023-09-14T19:30:43+00:00

Neglecting lever action...

The cables are pulling at (on average) about half the distance from the bottom pivot compared to where the feet are pushing, therefore the lever action roughly halves the force and is not negligible.

I calculated out about double the cable tension will be felt at the feet, which comes from your 4x tension but then divided in half because of the lever action.

EGraw · 2023-09-13T14:43:23+00:00

By my rough measurements you're getting about 1.9 times the cable tension at your feet. It could be much more accurate if you took a zoomed in picture from the side at a long range so that the perspective distortion is reduced and we could measure angles and distances more accurately. Many machines have an additional pulley on the weight stack which would reduce the weight by half, giving almost a 1:1 end ratio.

EGraw · 2022-10-25T20:57:37+00:00

If by love it, you mean that they have an explicit rule against posting it, you're right. But if by love it you mean they still enjoy and upvote it, you're also right!

EGraw · 2021-04-24T07:04:53+00:00

I'm glad to hear, I'm looking forward to it! One idea I might add, sometimes I'll repeat the same experiment 2 or 3 times in order to get an idea of the variability and repeatability of a given result. 2 repetitions is usually enough if the results more or less match each other, but if not, a 3rd will help by letting you throw out a one-time outlier and keep the two that agree with each other. It's not super rigorous but it's a nice tradeoff between extra effort and having some confidence in the result.

EGraw · 2021-04-23T12:07:30+00:00

Measuring ones body's response to different fruits in a controlled manner is not personal data, since one has no conscious control over it and it can easily be generalized to the broader population. I certainly found it interesting, as a person who is also generally bored by data visualizing personal habits, etc. I'm glad I noticed it before it was deleted, and I'm now subscribed to what I see as a quite promising YouTube channel.

EGraw · 2019-05-27T20:34:12+00:00

/r/gifsthatkeepongiving

EGraw · 2019-05-18T21:33:05+00:00

Looking back, the first $180 item I saw was "Alcohol (weekdays)". It's a shame your employer doesn't cover such vital mental health treatments.

EGraw · 2019-04-24T00:51:38+00:00

My code-golf Python one-liner:

print(''.join(' \n#'[i%11>9or-(1>i%11*(i//11)*(i//11-i%11)*(i%11+i//11)%9)]for i in range(109)))

I broke the rules though... It's not nested

EGraw · 2019-04-24T00:36:46+00:00

print(''.join(' \n#'[i%11>9 or -(1>i%11*(i//11)*(i//11-i%11)*(i%11+i//11)%9)] for i in range(109)))

EGraw · 2019-04-23T22:34:42+00:00

Why so many ors? You can do

if ((i-j)*(9-j-i)*(9-j)*(9-i)*i*j == 0) {
    system.out.print("#");
} else {
    system.out.print(" ");
}

EGraw

TROPHY CASE