You could do a whole “calibrating my…” series. I bet it would kill.

This guy is always thinking....the world needs a lot more of him!

5:29 - the descending C-major triad is really satisfying.

Matthias, you would have made an outstanding physics teacher, your explanations and examples are so educational and interesting. You make it all look easy. Thanks for the video.

Haven’t even finished the video, but the sight and sound of this thing makes spinning up is delightful and hilarious. Thanks for the videos Mathias

it never cease to amaze me (it shouldn't) the level of ingenuity and creativity in your approach to problem solving. just keep posting your videos, i'll keep watching them.

You'll most likely reach the lower limits of those mechanical anemometers in this experiment. Have you considered ultrasonic anemometers? There's no minimum force to overcome at lower speeds, and they also give you direction! You can map and figure out how the air is moving through your house, e.g. is it being deflected off of walls, door etc. You might consider buying a couple of the sensors to make your measurements... The experiment you propose to do is hard enough especially at low speeds... The reason you may want more than one of these to measure the wind's path because each time you walk through your experiment you disturb it and you have to wait for conditions to go back to baseline. I know they're pricey, you can consider to DIY them... Each anemometer needs 2 pairs of Ultrasonic transducers a sender and a receiver (like the Ping sensor) and you measure the time of flight from a pulse generated by the transmitter to a receiver... then the same thing is done with the other pair at 90 degrees, then crunch the numbers, do some trig to calculate the angle, you get a vector of the wind (speed, direction). I worked as a firmware engineer at a weather measurement company for 12 years, these are the very kind of problems in the field of measuring weather phenomena that comes up often, it's not as straightforward as people think... once in a while I get someone that can't believe it is that complex... and I'd say to them, if you think this stuff is easy, then clearly you don't understand the problem. For example: Solar irradiance needs cosine angle corrections, soil moisture sensors require AC signals to prevent migration of the sensing materials in the sensor, Rain has tipping buckets have errors at high rain rates and can't measure trace rain amounts... and last but not least... mechanical anemometers have low windspeed startup issues... not so easy after all... right?

Hot wire anemometer for low speeds, just as other said in their comments. Those are used in small airplanes (gliders especially) and measure to 0.1 m/s speeds. Just 1 wire and resistance measuring ( plus "heating current").

This makes me very happy inside. The amplified sound of a bit stepper motor is so satisfying. I'm getting "decapitation hazard!" Mythbusters vibes from that arm. R.I.P. Grant, we miss you.

I love the simple ASCII terminal plotter you use in all these videos. So useful! Would you be willing to share how you made that?

If this is what he does to get his $20 anemometer working accurately It's why manufacturers should send all of their devices to Matthias for review. They'd get a comprehensive videoed review they could put on their web site and 2000 pages of test data supporting his review for their R & D department to digest.

Fascinating as always. I don't know if it was your intention, but you proved the old saying, "One good turn deserves another"

Very interesting! What you need, for low wind speed is either an ultrasonic or hot wire anemometer (or an expensive laser Doppler anemometer), but the paper flap has low mass and seems sensitive enough for your project (and the principle has been used for ages, as a visual indication of wind speed on weathercocks - nevertheless a patent was granted for it in 1987).

I'm enjoying your fan experiments, and I am learning a lot, thank you. I live in a hot climate and have used fans coupled straight to a solar panel with a couple of resistors to move air in my tin sheds: when the sun shines, the fans blow. I hadn't got much further than that, but you are giving me inspiration to make it into something measurably useful :)

Your programming skills is awesome .

I love these experiments. I can see you are getting more and more confident with electronics and I am all for it ;)

I clicked on this video on accident. Never would i ve thought that watching someone calibratin a wind speedopmeter could be so entertaining

Interesting to learn house the air inside the house circulates. I’ll stay tuned due to sheer interest.👍

I was thinking model train. A long straight section can be filmed with a metered background, then you have a scale to calibrate to. Add the RPi to the train and access via WiFi or record to read later.

That is something I would hav loved doing or ever tried to do. Well done.

Haven’t got a clue what you’re talking about but I’m hooked😂

This kind of nerdy content is what youtube needs more of! I love it!

Welcome back to youtube! It had been a while since you posted that fan-distance from window video.

Nice tonic triad on the piece of paper.

You are genius, so elegant solution

Nice work as always. Thanks

It's pretty cool to see all these experiments, you can now write your own firmware y start selling accurate anemometers! 1:54 Time to start using string interpolation =) print("Initiate sweep, deg=",deg," freq=",freq) can be print(f"Initiate sweep, deg={deg} freq={freq}") (which I think is neater) and the same with the old % and the .format ones. I'm kind of jealous actually, I got so used at writing software "the correct way" (with object-oriented programming, unit testing, TDD and all that stuff) that I wish I could just wing it lol The only times I do it that way is during programming competitions where speed is paramount.

Love your problem solving. To avoid the twisting cable, maybe use an ESP32 and battery setup. To sync with stepper pulses, you can use a LED on the stepper pulses that flashes into a photo transistor connected to the ESP32. The other option is to time sync everything, I guess +/1ms is good enough. Nice idea on the flapping paper to measure low air speed.

This was really cool, thank you for sharing!

The random stuff channel is so good. Thanks Matthias

5:30 It's beautiful to hear the maths behind simple intervals.

The fan experiments are great!

You amaze me!

It might be worth considering using plastic instead of paper for your flap device. The paper catching humidity may impact the results, although perhaps too marginally to care about. Great stuff as always.

I'm a fan of this series

Ooooooo! So it's a series! I ❤️ a good series!

And yes, until this very day Matthias is still combing his hair with a balloon and making anemometers that can measure a fart. 😂

love your experiments. thanks

something pleasing about deriving an equation for a sensor output in excel

This has a chance of becoming Matthias main channel.

You make the most interesting experiments Can’t wait for the next installment

Going all the way for the fans, I see.

Pretty cool. A friend had an idea about how to measure low currents in a room using sound waves and calculating Doppler shifts. With an apparatus of known dimensions it should be possible to calculate speed and direction. Having several of them in a room, at different frequencies, might give a "picture" of the air currents. I don't think it was ever built, but I've always wondered now with fast computers how simple it might be (at the time he theorized about this 2400bps modems were in vogue).

dont dare give this man free time

Beaufort scale recalibrated to candle flame using a light sensor connected to a raspberry pi to measure flicker.

Aerospace engineer, swinging through the same air is not ideal, but in this case i wouldn’t worry too terribly much. As a non-lifting surface only the drag is really perturbing the measurements in future sweeps but for just a couple I think it’s unlikely to be a major contributor to your error here. They used to have rotating boom equivalents to wind tunnels that worked ok but did face problems with re-entering the perturbed air

Classic Mathias Wandel. Love it :)

Cool experiment, as always... measuring very low whatevers is always challenging... what about a big balsa wood propeller running on lubricated nylon or some low friction bearing? Now you have a way to calibrate it...

he is the most interesting man on the internet

Thank you for counting the toothpicks for the rest of us. :D

Put a conical cylinder in front of the meter. The increased speed would be easier to measure. Divide the result by the amount the cone mechanically increased it to obtain true air speed.

He’s one step closer to making his own halidron collider

Thats cool.

Don't know why, but I find the giant arm incredibly funny 😅

Meanwhile I’m trying to figure out how to open a bag of Cheetos without it ripping apart. And I’m failing at that…

I have need for a similar sensor. I was thinking of using a "whisker" instead of the paper, with a small strain gauge to measure the force on it.

Thank you.

I wonder if an alternative would be to disperse some chemical marker in the air that a device can measure. If you know the diffusion speed from a static air experiment, then you could calculate that out of the concentrations measured around the house and get values for the drift.

5:27 nice descending arpeggio!

Matt, for low speeds instead of deflecting a sheet of paper, you could consider a static orifice with a microphone to measure sound pressure volume, but you would probably have to calibrate that! U of W alumni.

I really like your clever ideas. Do you have plans for your low wind speed anemometer?

Have you tried using a large cpu fan and reading the pulses? You could use your rig to calibrate it. I assume it will have a higher breakaway torque because of the coils but would be neat to see a diy wind speed sensor. Love you low speed analog solution and test apparatus!

Would be neat to get a smoke machine or really just anything that produces somewhat clean smoke in there to visualize the air movements

Holy crap matthias.

Love the escalation. I'm betting this started with "it won't take that long" to "I need another camer!" :) I agree with others who said "here's how I calibrated X" series. Love it!

But boy does this thing sound coool

Engineer at work.

I feel like I learn more about RIM here than from the movie.

i would love to see a video of the reaction of your family to all that. we love to see your videos but they have to live surrounded by strange contraptions (unnecessary) Lol!!

There's probably me, you and 10 other folks that get this :)

Wow!

I've watched Matthias Wandel for years, but I bet I haven't 'Liked' more than a handful of his videos. Time for me to get my ducks in a row.

You can use slip ring so your wire doesn't get tangled

Yes more fan science🌬

The sound as the rotor starts up … :)

Neat

Very interesting. Why 2 meters? It seems that your life would have been easier with a shorter radius. Also, FWIW, if you soak the rims of the holes in your paper sensor with thin cyanoacrylate and allow it to harden (out of the apparatus that is), it will stiffen and be more robust. So you plan to map airflow in your home? I think this is a great project. Thank you.

Just go in circles: A management solution turned engineering solution.😂

Good on you for testing that . . . merchandise. Ahem.

Wouldn't it be easier to fill a room with "smoke" or with "prism" light and that way capture the air movement via dust or particles suspended in the air? I think the error factors are going to creep in at those super slow speeds any way to try to minimize it. Someone walking upstairs or downstairs or random knocks or creaking or settling or just temp and humidity changes might cause brief error readings right ? 😀

Nice setup. Have you considered not to measure the frequency at low speeds but rather the time in between pulses from the sensor? The ratio between max windspeed and very slow speed might be too big for accurate frequency measurements (in one frequency range). An alternative methode might be to increase the sensor pickup at low windspeeds by increasing the number of reflectionstrips?

You can also use smoke machine and lasers to see how air fills home

At 5:29, did you intentionally pick speeds that would make the motor hum in a major triad? :)

Instead of a peace of paper, maybe you could use thin material with much lower weight. And add a little weight on the bottom, for stability. In addition you could trying to create a cupped shape, so you receive more force, that will result in more accuracy.

Do you take in account the current air pressure? Measurements will be different under different air pressure conditions, because of the density of the air. Not sure if humidity has a significant effect on the ‘performance’ of the fan at the same speed.

wizardry

This is what happens at the Wandel household when the wife and kids go off for summer vacation (I'm supposing)

Could you also take measurements with a mass airflow sensor from a car? That might give your more precise measurements.

5:29 sounds like a chord or a key signature

Think the quadratic would have also the force of gravity like a pendulum right? That might fix your curve.

perhaps a smoke test would give you a visual representation of how the air is moving behind the fan

When we suggested an OnlyFans channel we weren't being literal!

could make a larger prop for the meter, or add a collecting duct.

If a fan blows in the other room, and no one is around to see a piece of paper move 2mm does it still move? Yes because there is a remote camera on it.

Would it be possible to measure the static pressure on a paper disc? Instead of deflection?

Looks complicated can’t you put it on the end of a pipe and blow air through at a given rate . Air circulating smoke or a thermal camera. I hung 9 temperature sensors in 3 lines from the ceiling floor and ceiling were 20 deg c different. Halfway between floor and ceiling was half way between two temps. When petting aircon fan on recirculate all sensors went the the half temp , after turning fan off all temps split again to original readings. Made some cool graphs

This measuring device only measuring the speed in 1 direction. You have any thoughts about a 360 degree measuring device? I’m thinking about a balloon upside down, with a needle glued on the bottom, and a circular scale. So you can measure the actual speed and direction in 1 go.

I was going in circles and then it struck me circles ... 😁

Why not a Venturi tube?

Why are you not teaching at a University somewhere? Intelligence like this should be passed on to others.