7 ms·
AppleWatchAmmeter
- kstrauser 2y agoThat’s genius in its simplicity. Wow. Well done!
- 8338550bff96 2y agoSimple genius is the only kind I recognize
- bri3d 2y agoSee also: https://phyphox.org/wiki/index.php/Smartphones_as_ammeters https://phyphox.org/wiki/index.php/Smartphones_as_ammeters - I've heard of some physics instructors using this in teaching settings. I'm quite surprised that nobody has made an app which can do some baseline calibration and produce real-time current measurements yet; it would just be a few hundred lines of code at most.
- _Microft 2y agoPhyphox is amazing: there is a wide variety of different experiments available using all sorts of sensors found in phones. The iPhone accelerometer seems to saturate at roughly 13g, easily achievable by pulling your phone very fast in an increasingly narrow arc towards yourself. What were you thinking how I found out? (Fun fact: this is another project that Sebastian Staacks of http://there.oughta.be http://there.oughta.be worked(s?) on. You might remember his wooden Gameboy shell, the Gameboy interceptor to screenshare the Gameboy screen to a PC or his bullettime video booth.)
- londons_explore 2y ago> iPhone accelerometer seems to saturate at roughly 13g That surprises me. As soon as a sensor saturates, you can no longer use it for dead reckoning (integrating the acceleration values to know position). 13g is way below what you'd expect when tapping the phone against a solid object for example - that could easily reach 1000g briefly. I was under the impression that a big part of iphone's superior GPS performance was down to the clever use of dead reckoning and re-calculating past datapoints in a way android manufacturers rarely do.
- foldr 2y agoAny 1000g acceleration is going to be irrelevant to the position of the user of the phone (or they’d be dead!)
- londons_explore 2y agoTapping your fingernail on a hard surface, your fingertip experiences ~1000g. Big g-forces are bad if experienced for more than a few hundred microseconds. But very briefly, they aren't too damaging.
- foldr 2y agoSure, but if an entire human person is accelerated at 1000g for a period of time that's long enough to lead to a significant change in their location...
- avianlyric 2y agoI don’t think the iPhone does naive dead reckoning like that, as the sensitivity of the needed inputs is so high for it be reasonable in a consumer handheld. The cost of components would be way to high, then there’s the issues of power consumption, because you would need to poll all your sensors at a very high rate to get enough accurate data to perform naive dead reckoning accurately. Instead I think the iPhone cheat a bunch, and use a mixture of step counting, magneto and gyro inputs to perform dead reckoning. The iPhone uses periods when you GPS is in use anyway to calibrate your stride length at different speeds, which when mixed with magneto data to estimate a course direction, would allow an iPhone semi-accurately perform dead reckoning, without needing high resolution, wide scale, accelerometer input. In short, the iPhone cheats. It’s dead reckoning systems take advantage human bio-mechanics to simplify the problem of dead reckoning, at the cost of building a dead reckoning system that only works effectively in a handheld device that semi-permanently lives on your person. A perfectly reasonable assumption for a phone, but a terrible solution for a more generic dead reckoning system.
- nielsole 2y agoIf my math is right, assuming an iphone deforms linearly on impact with 1000g deceleration, it would only give way 0,7mm when dropped from 1m height onto concrete. that seems too low a deformation? I would expect it to whobble quite a bit in slow-mo.
- radicality 2y agoThanks for that recommendation, really good app. In today’s app landscape it’s almost unbelievable that it’s so polished and free and without ads / signup links / always-on location sharing etc. It’s not even easy to find. Few months ago I wanted a simple audio spectrogram app, downloaded some which wanted dubious in-app purchases, or had ads. I hadn’t come across it earlier, but Phyfox does what I wanted better and for free.
- nvalis 2y agoThat's because Phyphox is financially backed by multiple public bodys of the German governement, mostly the RWTH Aachen and the Federal Ministry of Education and Research as pointed out on the landing page [0]. [0] https://phyphox.org/ https://phyphox.org/
- maven29 2y agoAll you need to do is to start your search on f-droid, the app quality is much better (also consider adding the IzzyOnDroid repo if you don't care about verified reproducible builds)
- _Microft 2y ago> A circular coil of wire with N turns and a diameter D will generate a magnetic field of B = u0.I/D (u0 is defined to be 4.π.10^-7); That u0 is meant to symbolize μ_0 (mu zero, with zero being subscript) the vacuum magnetic permeability [0], in case you were wondering where that magic constant came from. [0] https://en.wikipedia.org/wiki/Vacuum_permeability https://en.wikipedia.org/wiki/Vacuum_permeability
- lapetitejort 2y agoSee also ε_0 [0]. 1/sqrt(ε_0*μ_0) = c, the speed of light [0]: https://en.wikipedia.org/wiki/Vacuum_permittivity https://en.wikipedia.org/wiki/Vacuum_permittivity
- cdchn 2y agoIt would be cool to use this as a voltage sensor, to check for live circuits, but the downside being you might not want to crane your wrist towards said live circuits.
- atoav 2y agoAnd: measuring current can be done with any odd hall effect sensor, voltage not so much. I imagine a smart warch with two 4mm banana-jacks isn't going to be the next big thing.
- cdchn 2y agoThe pen size of my non-contact voltage detectors make it feel like it couldn't be THAT hard.
- ComputerGuru 2y agoAs TFA mentions, detecting AC current is rather different from detecting DC current (the article is about the latter).
- deleted 2y ago[deleted]
- boomskats 2y agoOnly somewhat related, but wasn't there a DIY biohacking[0] craze a few years ago, with people implanting rare earth magnets into the tips of their pinky fingers, waiting for the nerve endings to heal around the implant, and then supposedly gaining a 'sixth sense' of being able to detect the flow of current via their bionic pinky? Is that still a thing? [0]: https://www.wired.com/story/diy-biohacking/ https://www.wired.com/story/diy-biohacking/
- deleted 2y ago[deleted]
- Gracana 2y agoI recall Zoe Quinn wrote about having that done ~10 years ago. Article's still up on her site, it's a good read: http://www.beesgo.biz/magnet.html http://www.beesgo.biz/magnet.html
- gxs 2y agoWhat am obnoxious mobile site you’ve linked to - unusable because of a persistent floating graphic over the middle of the screen.
- zitterbewegung 2y agoYes, there was but the magnets can break and I believe getting them removed is hard.
- Spivak 2y agoGiven how well-trodden putting hardware in humans is, I'm surprised this wouldn't be a <60 minute surgery to affix the magnet to your bone. Then it wouldn't look so weird pulling on your skin. Then again, the non-invasive version is wearing a magnetic ring, $1.34 on Aliexpress.
- ramses0 2y agoSimilarly: supposedly superglue a magnet to your fingernail.
- brcmthrowaway 2y agoI wish Nokia was still around, this would be turned into a feature. Think N95 was a smorgasboard of random features.
- dcreater 2y agoN95 is one of the GOAT phones. I hope for a day in the future when phones can once again be as diverse and fun
- dang 2y agoWe changed the URL from https://hackaday.com/2024/09/10/the-apple-watch-as-an-ammeter/ https://hackaday.com/2024/09/10/the-apple-watch-as-an-ammete..., which points to this. Submitters: "Please submit the original source. If a post reports on something found on another site, submit the latter." - https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- deleted 2y ago[deleted]
- deisteve 2y agohtis is a great hack! I've been looking for a way to measure DC currents without breaking the bank. Has anyone tried using a similar setup with a Raspberry Pi or an Arduino to create a more robust and accurate measurement system?
- C60H92O6 2y agoI advise you to add a disclaimer at the bottom that says "this is for educational purposes only, try it at your own risk and don't rely on it for serious/dangerous measurements". And also change the name to "Ammeter for Apple Watch", as some "special" people might think that this was made by Apple. (My learnings from almost getting sued for a simple hobby project like this)
- ActionHank 2y agoGive it a week and these will be for sale on etsy, ali, and amazon.
- mightyhacker658 2y ago[dead]