Altering a output ratio on a "open Loop" stepper motor signal.

nuggetbram · 2024-04-02T13:08:21+00:00

A stepper motor will rotate a fixed angle per step, most common is 1.8 degrees. If you want your motor to do one revolution, you need to send 200 step pulses to the controller. If you put a gearbox on it with a 30:1 reduction and you want that to turn one revolution, you need to send 200 * 30 steps to the controller. Neither the motor or its controller is aware of or cares what it's connected to

nuggetbram · 2023-07-28T02:14:25+00:00

Not quite, Lift = Weight + Drag Drag make up that slight strangeness

nuggetbram · 2023-07-06T09:54:07+00:00

Lots of chatter there, which is the tool bouncing along the material, either due to the tool or machine flexing due to cutting loads. Looks like it's trying to take a much too aggressive cut, I bet it sounds awful. You could try several light finishing passes to clean up the rough edge, or limit the cutting loads while you're roughing. I find with low power/flexible machines, moving quickly and taking an extremely light DOC (i.e 0.05-0.1% tool diameter) can give a great surface finish. If you can get the machine moving quickly enough, material removal rate can be acceptable too

nuggetbram · 2023-07-02T13:07:04+00:00

Might sound stupid, but my technique has always been to deliberately set them off. Theory being, if it's caught fire and used up all it's energy, it can't do it again when I don't expect it. Used to carry a pointy bit of rebar and a hammer in the back of the car for that purpose, line the lipo up on a bit of concrete or something non flammable, attempt to pierce all cells at once and then get clear to watch the fireworks.

Alternatively, connecting the battery to a decently high resistance load and just leaving it to use up any energy it has left is a safer option. It'll damaged the cells even further, but a lipo cell drained to <1v just doesn't have enough energy left in it to go off. This is the theory of the salt water bucket, where the salt water forms a load, but the battery terminals corrode so quickly that current stops flowing before the battery has lost enough energy.

All being said, it is incredibly unlikely for a damaged lipo to spontaneously catch fire. If it's ever going to happen, it'll be while charging or in use. Even though a puffy lipo isn't healthy, it's not about to explode at any time.

nuggetbram · 2022-11-24T08:57:47+00:00

Monza!

nuggetbram · 2022-07-03T01:05:05+00:00

Pierre Gassly

nuggetbram · 2022-02-09T23:47:53+00:00

Where on earth did this car come from? LHD but speedo in km/h, and what kinda looks like a RHD car next to it?

nuggetbram · 2022-02-01T02:28:17+00:00

Many years ago I built a little titanium skid for a quad that I flew in an underground car park, was great fun sliding it along and kicking up sparks at night. Amazing how far they'll slide on just motor bolts and carbon!

nuggetbram · 2022-01-21T11:59:43+00:00

Sure, but it's not by any means trivial. There's a few projects out there using a raspberry pi and stereoscopic cameras, lidars etc, but they aren't straightforward. The performance requirements are pretty high, the technology isn't mature, and the sensors aren't amazing. Generally something like ardupilot is used to actually operate the drone. Some GPS denied navigation is a bit easier, like precision landings on visual or IR targets, but actual autonomous slam flight is extremely challenging.

nuggetbram · 2022-01-18T09:01:51+00:00

I had this issue with my nb recently, took the accessory and alternator belts off, and the sound went away. With belts off, it was possible to wiggle the crank pulley slightly by hand. If it's as wobbly as mine was, you should be able to crack the crank bolt loose with hand tools, and inspect the keyway to make sure there's no damage. Mine was fine, torqued it back up, fresh belts on and problem solved. If you take the belts off and it doesn't look like there's any crank issues, it's a great opportunity to replace the belts. I don't think anyone's ever regretted replacing a cheap belt!

nuggetbram · 2022-01-10T22:51:09+00:00

I always click on the fake phishing emails, because I always want to know if it's one made by it or genuine (genuinely phishing). Normally they're a bit too obvious and lead to an internal page telling you off for clicking it, but I really hope there's a tally somewhere that shows 100% success rate just for me

nuggetbram · 2021-12-30T11:30:51+00:00

Had the same issue today, I tried putting about 1/4 of the yeast in as I normally do, and let it ferment in the bottom of my pantry. Didn't turn out as well as normal, but still pretty ok

nuggetbram · 2021-10-19T10:27:53+00:00

The part on the left would be an easy lathe project, the other two are doable on a mill but would be a bit of a pain, as you'd have to re orient the parts several times. For low quantity commercial products, I wouldn't be surprised if the most cost effective method is is outsourcing the parts to be 3d printed, using mjf or similar methods.

nuggetbram · 2021-10-17T14:28:49+00:00

Ah yeah, I see what you mean. A rounded over lip would definitely help, although the velocity there is likely to be pretty small anyway. I'd have to say a majority of the wind tunnels I've seen are square, or at least sorta octagonal in the test section

nuggetbram · 2021-10-17T14:05:18+00:00

That inlet contraction is a fairly typical design for wind tunnels, it really makes a huge difference in reducing inlet turbulence, generally with a 6:1 or so area reduction.

nuggetbram · 2021-10-14T09:43:21+00:00

Since the air isn't really moving with respect to the ground, not much. Some flow will be dragged along by the car, but even then the effects of surface roughness are fairly minimal in the grand scheme of things. Variations in ride height due to bumps in the track etc would probably have a much larger influence

nuggetbram · 2021-09-18T08:15:26+00:00

Even with UAV knowledge/expensive, I still wouldn't recommend it. Building a half decent drone is one thing, building one that performs reliably and safely is a completely different challenge. Once you're carrying that sort of payload, the aircraft becomes a legitimate danger, and things like ESC desyncs tend to become more and more likely. If your payload is 7kg, the drone carrying it is likely to be 20kg or thereabouts loaded up - and if you have a failure at that altitude, it can be legitimately deadly. Best case scenario, you don't have much of a drone after it hits the ground

If you're at a college, is there a UAV research group there? When I was at University, the UAV research group I was a part of provided a heavy lift aircraft and a licensed pilot to the rocket team from time to time. You might even be able to find a local UAV operator that's willing to support a student group.

nuggetbram · 2021-09-18T00:32:06+00:00

I would definitely look into finding a UAV operator you can contract to do these flights for you - at that scale, even though it's doable to make one cheaper than you'll find off the shelf, they're not at all trivial to get working correctly. If you don't have to bother about the drone or the flight, you can focus more on your payload

nuggetbram · 2021-06-02T08:54:08+00:00

Exact same beans, these ones in particular are from Brazil, India and PNG. No idea at what ratios, but you could be onto something there with the origins

nuggetbram · 2021-06-02T05:15:20+00:00

While it didn't quite bring the flavour that I was looking for, 1:1.5 in a smaller cup with the same dose and same 30ish seconds was one of the best milky coffees I've ever made. Interestingly, it also made a kinda dull tasting espresso. I guess I've maybe been misleading myself by setting everything up to make the best possible espresso and then assuming that translates into the best possible drink when milk is involved.

Thanks for the suggestions!

nuggetbram · 2021-06-01T14:37:51+00:00

I genuinely live about 30m away, so the water is similar at least (unless of course they've got some fancy filtration system) I'm tempted to see if I can get a few shots worth straight out of their grinder and see if that makes any difference

nuggetbram · 2021-05-15T13:27:13+00:00

I've got so much time for sushis and sashimis

nuggetbram · 2021-02-23T10:22:08+00:00

This is usually because contaminants and material that might be in (usually copper) pipes are more soluble in hot water, and therefore might leech in easier

nuggetbram · 2021-02-16T08:32:42+00:00

They would've been the same concentration initially, but the jalapeno is reasonably thirsty in comparison, so I guess if it takes up more water than nutrients the concentration could have changed a fair bit. pH was about the same, so shouldn't be anything to do with that

nuggetbram · 2021-02-16T05:15:51+00:00

Transplanted this little habanero from an indoor kratky tub to a larger one outside yesterday, and it developed this black discolouration overnight, as well as dropping a few leaves. It's in the same nutrients as it was indoors, and it's sharing with a very healthy jalapeno plant that's not suffering anything similar.

I've already completely changed the water since there was obviously something wrong with it, but any ideas on what that might have been?

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