Temperature-sensing RFID tag in magnetic stir bar

[@Nighthawkinlight]

Excellent idea, that would be real handy.

[@SodiumInteresting]

Yes next we need a simple diy rotovap design using cheaply available parts 🙏

[@amarissimus29]

Especially if you're tearing your hair out because all of your probes are dissolving, screwing up your readings and contaminating your reagents. The kind of idea that solves a very perplexing problem particularly perfectly. I'm now thoroughly embarrassed at all of the laughable workarounds I created, half of which bricked expensive gear.

[@SaltNBattery]

Hey, you guys are awesome. I just wrote a comment saying how amazing it is that I can watch an Applied Science video about something I've never been interested in or had any use for, yet I'll still watch the entire video, fascinated while learning how to make this thing I'll never make. The same is true for NightHawkInLight and Tech Ingredients. You all are awesome educators.

[@marcmarc172]

Always producing high quality, interesting videos throughout all these years. Applied Science is one of those KZbin treasures, you know?

[@pantherplatform]

Estd 2006

[@CHZMN1]

Oh hi, Marc.

[@spagamoto]

Yes! His stuff needs to outlive the platform, when its time comes.

[@mkeenan641]

He’s a treasure of a human being

[@SireSquish]

This seems amazingly cool. In another thought, having glassware that can log how many cycles it's had gives me visions of DRM glassware and Dymo style lockout shenannigans.

[@MrJeppeholt]

this is really cool. cant believe no one have done this before it seems really useful

[@saml7610]

My guess is, the reason no one has done this is because the stir bar is in direct contact with the bottom of, and the bottom of the beaker is in direct contact with the hot plate. The temperature being measured is not the temperature of the solution, but rather, it is somewhere in between that temp and the temp of the hotplate itself (often very different). This is a nifty idea, but it would need to change the arrangement of the magnets so the stir bar "levitates" instead of remaining in contact with the bottom of the beaker, otherwise it will be imprecise.

[@HerbaMachina]

@@saml7610 I guess it's useful in pairing with another external probe to get a better idea of the overall temperatures of the solution.

[@Bobbias]

​​@@saml7610 honestly, I doubt the error on the stir bar's readings would be particularly meaningful. Only a relatively small amount of it's surface is in direct contact with the bottom of the beaker/flask, while the majority is in contact with the surrounding liquid. And it's not like your average thermocouple is particularly accurate either.

[@saml7610]

@@Bobbias Yeah, that's a good point. I assume you could design a slightly modified stir bar geometry that has an even smaller contact patch than the existing ones already do, and that would address any issues. At that point, you're right, you'd get more error from the sensor itself. Rarely do I even need very tight temperature control in my day to day, other than a few esterification reactions that utilize more temperamental catalysts (not Grignards reagents, those tend to be forgiving, although they can form a very nasty crust on the beakers if you go too high).

[@grantofat6438]

Because it isn't needed.

[@KeanM]

To anyone wanting to reproduce this... while the eZ430-TMS37157 dev kit is no longer available, you can still buy the TMS3705 which is the main component used on the "base station" (reader) PCB. There is also appnote SCBA031 for adding a MOSFET driver chip for longer range. It might also be possible to source the MRD2EVM reader which is similar, or RI-STU-MRD2/RI-SMD-MRD2 modules. I still maintain a bunch of 134.2kHz RFID readers in penguin monitoring systems.

[@cameronwebster6866]

As in monitoring tuxedo birbs, or is it a brand name?

[@KeanM]

@@cameronwebster6866 yes, the tuxedo birbs 🐧 There are RFID readers and weighbridges for the little penguin colonies on Phillip Island Australia (I just returned from a maintenance visit there) and readers for both little/blue and Fiordland/Tawaki penguin colonies on NZ South Island. There are also similar monitoring systems in Antarctica of course, but I’m not involved with those. And yes, we use Linux!

[@cameronwebster6866]

@@KeanM cool! How much if the stuff you fix is penguin damage vs. environmental?

[@jimmy2drinks]

@@KeanM Me & my better half visited those guys on the breakwater at St Kilda beach in 2015. Sounds like a cool job you've got

[@KeanM]

@@cameronwebster6866 I don't think the penguins cause much damage apart from their "deposits" needing to be brushed off the weigh platform regularly (auto tared anyway). The big problem is of course corrosion, with equipment being right on the coast in full open air, followed by pests like ants and rats. Things need to be sealed tight or else wont last. Most of the electronics has survived well though, and just metalwork, connectors, and cables needing occasional replacement. The humans do break things though on the portable readers, as they get a bit of abuse in the field.

[@b0rd3n]

I'm glad you are making this open source. Thank you for your work and content. You are my favorite content producer on YT for certain. Some things are way over my head but your explanations and failures/attempts make it for a very understandable 'product' in the end. THANK YOU. From Canada with love brother! Take care!

[@great__success]

8:14 somebody send him LTT screwdriver :)

[@HuygensOptics]

Very nice concept, Ben. One of the chemical aspects I was immediately worried about though was chemical resistivity. Standard stir bars have teflon coating which is chemically inert but is sintered at high pressures and temperatures (above what would be considered suitable for electronics packaging). Virtually any other polymer is either not resistant to strong acids or bases, or to strong solvents, especially at elevated temperatures. I did not hear you say it in the video, but is that maybe one of the reasons why you did not pursue his as a product?

[@eelcohoogendoorn8044]

I think you could simply do something like a piece of PTFE shrink tube, welded shut at the end? If you leave a cm spacing or so from the end and you put in a piece of glass fiber wadding I imagine melting shut the end of a glass tube should also be in the cards?

[@HuygensOptics]

@@eelcohoogendoorn8044 Yes that is also possible, I did not think of that. As for chemical resistivity, teflon is generally superior to most glasses (which are still quite sensitive to acids and bases).

[@irreverend_]

Assuming he 3D printed the bar housing there, PLA is an absolute bugger for not reacting with any chemicals. If you print in ABS you can use acetone to smooth the prints, etc etc. I have only heard of, never seen, any solvents that actually affect PLA, and the one you'll see tested really doesn't. Chloroform apparently does, but I've yet to see someone test it. Otherwise PLA is essentially inert. Of course producing it as a product you could just factory produce various materials for the housing. Ceramic, glass and plastics. But seriously, almost nothing but time and UV (and any temperature over 80°C I forgot about that for a minute there) affects PLA.

[@suruadamable]

@@irreverend_ PLA degrades in high pH-s really fast. And as you sad softens on low temperatures, even in hot water, it is useless in lab.

[@irreverend_]

@@suruadamable but of course you could commercially produce any number of materials. There's setup for making hollow stuff in that shape already, all you need to do is add a small PCB inside. Most of those components will take high temperature for a short time but ceramic cooldown could pose a problem. However multiple different materials would suit different applications. Ceramic or glass are going to be the ones you want for something more universal, and they would cost more, assuming there's a way to get the electronics inside without melting them. Probably make one hollow and then quickly weld the end on somehow. It's how I'd make a metal one anyway.

[@boltzbrain3039]

i love magnetic stiring, and this is the biggest tech advance in this field for the last 100 years of magnetic stiring history! Huge respect for opensourceing it

[@austintabulog2661]

Casually drops one of the most innovative designs for lab equipment I’ve seen. Great work!

[@mikeselectricstuff]

I've done some playing with RFID stuff - the drum core inductors work OK, but if you snap off the top, to make a T shape core, it works way better. I never found a source of ready-made coils like that, or custom ferrite.

[@p_mouse8676]

I know sources. You could even ask companies like Coilcraft. But the issue is that they always need MOQ's of a couple of thousands usually. It would be interesting if a Pcb coil could be made on a multi-layer board.

[@Kai-ml2iu]

​@@p_mouse8676 Yes, PCB coils are possible (and IMO even the best option for this application if you can find the board space to spare). I used them in custom RFID tags for a seminar course a few years ago. The bigger the area, the better: higher inductance and better flux coupling. Then just tune the capacitor as needed.

[@mrnmrn1]

@@p_mouse8676 Some Chinese OEM would probably make them in lower volumes and much cheaper.

[@tinygriffy]

Snapping off the top.. brilliant tip ! .. I saw a modified 3d printer winding custom coils via the filament transport stepper lately... umm.. channel is called homofaciens I think.

[@JohannSwart_JWS]

Excellent idea, and implemetation. As a frequent ex-user of stir bars in the lab, the size is a bit on the large side. We mostly used much smaller ones, so I think it must be possible to reduce the size quite a bit with some fiddling, to make it more practical. I do realize its a proof of concept though. Thumbs up!

[@sleepib]

Making tools is often just as interesting as what job you need the tool to accomplish.

[@billyjones9907]

I can't even count the number of times something like this would be helpful. Great idea! I wouldn't be surprised if Thermo or Fisher sells these in a year or two. I had no idea things like this were already patented.

[@TheTheRay]

I can already imagine the pricing: 1500 USD per base. 120 USD per stir bar. 200 USD for a large stir bar.

[@gus473]

​@@TheTheRaySeems about right! 😉

[@dogefort8410]

​@@TheTheRay it's for science. Build cost +10% and shipping. This is 100% a case for crowdfunding a product into existence, if nothing else to discourage obvious price gouging.

[@AppliedCryogenics]

Needs a black-and-white film-grained scene of Ben, with an exaggerated expression of sad frustration, completely tangled up in the temp probe lead, as a a deep professional voice-over asks "How many times has this happened to you? Old-style temperature probes are awkward and inconvenient, but now there's STIR-BUDDY 9000!(tm)" ... " BUT WAIT. There's more! If you call within the next ..."

[@rootvalue]

I just love you. Your videos are some of my favorite and you are a benevolent scientist, constantly giving back to the community.

[@BackYardScience2000]

I'd pay whatever you wanted for this device. Seriously, I do TONS of chemistry and this would help me and solve so many problems! I'm drooling over this, man. Thank you for posting, but I am insanely jealous. Hahaha!

[@marklundeberg7006]

Based on the patent talk it would be unwise for him to sell it. He won't even charge money to his patrons for this! Wise move of him to stay very clear of legal troubles 🙂.

[@zombieregime]

Please, do not drool onto Ben.....

[@pokojnitozo2360]

Where are you from? Maybe we can make something...

[@MrJeppeholt]

google "SmartSense stir plate". But the price is honestly ridiculous 100$ for the stir bar and 2275$ for the hot plate.

[@mikeselectricstuff]

Low frequency RFID is quite easy to do with no special silicon - for the base, a series tuned LC circuit driven form a half-bridge ( can use HCMOS outputs at lower powers, MOSFET drivers are good for higher power), with a simple diode detector, opamp and data slicer for receive. The tag end can also be done fairly easily if you don't need ultimate range . ST did an RFID tag chip with a host interface so you could write its eeprom to control what it set back - don't recall if this was LF (125/134K) or MF (13.56MHz)

[@mikeguitar9769]

Thanks Mike. I was thinking, if the LC oscillator had a monotonic frequency vs temperature characteristic, then maybe it could be used as a frequency modulated temperature sensor.

[@billynomates920]

this channel is so far beyond me - i took chemistry, physics and maths between 16 and 18, engineering after that. degree i never used. forgotten 9999%. stem still really interests me but its 30+ years. i love watching these videos, pretending to be a fly on the wall seeing all the now and how. wish i'd kept up... anyway. 👴😃

[@dylanberger8701]

babe I can't come over, new applied science video just dropped

[@apbosh1]

I've just finished a multi stage programmable temp controller, wireless to an app, we're all at it. What you made here is brilliant! thanks for the upload most interesting and great idea/build

[@AlexBesogonov]

One thing, stir bars are absolutely notorious for picking up crud on their surface and causing all kinds of unanticipated reactions. If you work with sensitive chemistry, you often need to go through dozens of stir-bars within weeks. When I was working in a dirt-poor university lab, we actually just used paperclips pushed through molten glass. So it'd be interesting to think about changeable "shells" for smart stir-bars.

[@leocurious9919]

What sort of sensitive chemistry was that? I have never had an issue like that (or heard of it), even with tiny amounts of trace elements like in an ICP-OES.

[@AlexBesogonov]

@@leocurious9919 Various metals, mostly. They were causing all sorts of unwanted catalytic reactions. Palladium was the worst offender.

[@EdwardTriesToScience]

perhaps some sort of glass capsule, maybe a regular old ampoule but they are a bit thin but definitely could work, after the bar is near the end of its life, smash it and put the module in a new one

[@rich1051414]

I would think an enterprising person could design hollow stirbars that screw together, where you can add a smart device inside or throw a neodymium magnet inside and use it in dumb mode.

[@urjnlegend]

@@rich1051414 I thought in this video that's what that was, just a shell. Basically two halves stamped together

[@fatiheneskuru4332]

I wish i could do apprentice ship in your lab, i love your work, the creative aspects, the reverse engineering, your projects are joy of science in purest disstilled form.

[@WmLatin]

I wish I had some of those capabilities in MY lab stir bars years ago! ;-) I hope someone is able to produce these as an actual product in the future... great idea!

[@zombieregime]

Unfortunately, like many interesting fields, the niche-ness of the field is still low enough that the only real players are those with vested interests and funding. ie, the equipment suppliers dont have much incentive to drive prices down (IM LOOKING AT YOU MICROSCOPE MANUFACTURERS!!! Freaking highway robbery in some places....). One, because....97% of the customer base is funded by government grants and universities, so deep pockets, and two even with the high prices making back the product R&D is a bit of a bear. On top of the patenting issues. Sure, patent holder A might be perfectly fine with anyone producing it as long as they call it a "Dohicky Delux 2000" but if patent holder B whos devices A's is used with wants all the monies, you're SOL. The good news is a decent patent basically tells you how to make one. And you can make whatever you like for your own non-profiting personal uses. You just cant sell it without a patent license agreement. Take the CNC realm for example, we could have had 3d printers in the 90s. Every paper printer had 90% of the equipment needed. But the control scheme was patented, so until that ran out no one could market 3d printers making the bar for entry very high where it came to producing the needed hardware and such. Basically, capitalism ruins innovation. Well, specifically greed, but greed tends to ruing everything.....and thats coming from a capitalist 🤣

[@irreverend_]

Hopefully he produces some. It's good being open source but it does seem that there's demand for it and he deserves something other than just recognition for the idea

[@MrJeppeholt]

someone have just google "SmartSense stir plate". But the price is honestly ridiculous 100$ for the stir bar and 2275$ for the hot plate.

[@ersetzbar.]

this is really impressive, I can imagine that the precision you could possibly gain from this could speed up research significantly

[@RexusKing]

I'm surprised that: 1. This is not already a existing product, it's super useful for lab work 2. You are giving all these out for free!!!

[@tissuepaper9962]

"If you're good at something, don't do it for free" was never true. If the goal of your research/inventing isn't to become fantastically wealthy, but rather just to help people, then it isn't a surprise at all that one might release a potentially valuable idea for others to use _ad libitum._

[@dedamarsovac]

Hey, that's my area of expertise! :D I've designed a few unusual and high-performance 134.2kHz HDX readers, to the point of having separate TX and RX amplifiers and even coils. Even though most were based around the same TMS3705 that you're using, I've managed to get a read range of more than half a meter. I know there's not a lot of info, but I volunteer to explain anything that I can. -Coil diameter: Assuming the RFID tag is a single point (valid assumption in this case), the ideal coil diameter for the best coupling would be about twice the range you're hoping for ( so that radius = distance from center) Larger coil puts wastes magnetic field energy in a large volume, and smaller coil keeps too much in one place. Magnetic fields fall down fairly abruptly because they are dipoles. -Input power: has to be (at least) enough to create a large enough magnetic field in a coil you're using. It could go very low with a superconducting coil, but hey, it's copper. If you use more copper, the power could go lower. Too much power can't hurt, but it can melt the coil or overload the power supply. -Coil inductance: not important by itself., but related to the input power and Q-factor. I've had many single-turn coil designs that could then be integrated into structures. Great for EMC! More important quality is the ESR of the coil. If your power budget is 1W, choose a coil such that the ESR@134kHz dissipates 1W at the voltage it's getting. If you need 10ohm ESR, and your Q factor is around 5, you need Measure the coil in-situ, because the nearby structures can add a lot of ESR (induction heating). -Tuning the coil: Beware of X7R capacitors! Ceramic capacitors (except NP0) are very nonlinear with voltage, and they're impossible to properly tune. Use film and/or NP0 capacitors instead. Also note that voltages can get to XXX Vpp. For good transmission, tune for the highest voltage when the coil is in its place. For good reception, and if your coil has a high Q-factor, tune for about 128.6kHz ( between the high and low bit frequencies of the FSK downlink) -Reading range: it can be limited by either TX or RX part. Put an air-core coil near the tag just as a probe to see when/if the tag sends the whole response back to the reader. If there is not enough power, the message from the tag to the reader doesn't get finished. If it gets finished and the reader doesn't receive it, you could work on the RX part. In your case, I'd bet that the SMPS nearby produces a LOT of magnetic noise that is picked up by the coil. they usually work at around 65kHz, which makes a harmonic right at the 130kHz where your RX part has to be the most sensitive. Test with a battery to compare. I recommend shielding the SMPS or using an old-school transformer.

[@dedamarsovac]

oh yeah, and excitation should be at least about 5ms to get a response. Around 20-30 ms is good enough, but it depends mostly on the capacitance inside the tag. 50ms is usually more than enough. Since this is a DIY tag which can have a much more beefy capacitor, I expect a bit more, but I wouldn't ever go over 300ms. If it takes 300ms to charge a capacitor in the tag, then the tag should be improved, usually they all stabilize after 50ms of charging.

[@dedamarsovac]

Oh I left the example unfinished: If you need 10ohm ESR, and your expected Q factor is around 5, you need 50 ohms of reactance @134.2kHz , which is around 60uH. If you'd have a Q factor of 20, the design inductance would be around 240uH (+j200). And ofc. a capacitor that matches the reactance and can withstand the voltage (= expected current * reactance , which could get to 100V in the latter example if driven by 5V)

[@Kumquat_Lord]

Thank you for open sourcing this. This is an absolutely brilliant invention that I'm super surprised hasn't been invented yet.

[@ericlotze7724]

Seriously though, this whole “i’m done messing around with it so I’ll Open Source it” method is SOOOOOO good and important. It may be sitting on a shelf and disinteresting to you, but if someone else finds it interesting and maybe iterate on the concept a bit, things start to get interesting real quick!

[@KamiThulak]

This is so good its scary. How did no one come up with this yet? This is incredible.

[@alexportiiii6414]

When you point out how awful the current temperature probe setup is, I found myself muttering amen brother. Very nice build. All the best to you. Thank you for sharing this

[@flydiscovery]

There are so many times in my work life when this world have been incredibly useful

[@zombieregime]

"I guess it want that hard to reverse engineer" .....says Ben. Guy builds his own x-ray machine, magnetic resonance whatsit, mass spec, and still drops that humble bomb on us with a little giggle. Damn it Ben, stop being awesome! .....No, dont stop being awesome. Really cool work, mate. Id love to see this idea picked up and the maker crowd come out with neat chem equipment. My first toe dipping into chem techniques was distilling ethanol out of cheap booze in glassware that had rubber stoppers. Had to modify a bung for 3 holes, one for the bubble elbow, one for the mercury thermometer, and one for a long stem funnel for adding more booze. Didnt have a pump for the condenser jacket so I set up a pair of buckets (one on the table, the other on a chair) to run as a siphon, when one ran out, swap em around and start the siphon again. The next run I did was homemade HCl via the Mannheim reaction (IIRC, its the sodium bisulfate + table salt one) since we had some old pool chemicals laying around. That was the night I discovered what a lovely shade of "DO NOT BREATH THIS" yellow-green death chlorine gas is (yes, I had ventilation, still it was an interesting experience. Pucker factor 7 event). Ended up being the first glass lampwork I did too, made a U bend tube from some narrow tube straights for a double flask backflow rig to catch the suckback at the end of the reaction. Learning experience 10/10, would do again. Risk level 4/10 would not let my kids do that unsupervised (like I was 🤣 But at least I wouldnt accuse them of making drugs just because there is a white crystalline mass left over in the reaction vessel.....like I was 😒 Do you know how hard it is to explain a reaction and the resultant compounds to someone who thinks "ermuhgurd laboratory glassware cops gonna kick our doors down" ......Its quite annoying to say the least......) Anyhoo, Ben, youre a paragon in the garage scientist world. Dont ever stop being awesome. And thanks for the content! Your work does not go unappreciated round these parts 😉

[@wobblysauce]

That was a great breakdown of the modifications, and the top being clipped in is really good for thermal expansion, just floating on top.

[@SaltNBattery]

99/100 you make something that I have no use for or any prior interest in. For example, I'm not a chemist and I've never done any "real" chemistry outside of school. Yet I'll still watch this entire thing without feeling bored. Have you ever measured your IQ? It's gotta be off the charts, it's always amazing seeing the engineering and creativity in these projects.

[@ClownWhisper]

My God I would love to have this I've done so many reactions where I have to stir for 24 36 plus hours or more only to come back and find my stir bar bouncing around. This is very very very good idea

[@tanchienhao]

We need more open source science equipment like this!

[@dogefort8410]

I nom nom nominate the pi foundation to do the innards and crowdfund a decent packaging into being a thing

[@michel5148]

even though i'm not a chemist, i can clearly see how handy it would be. elegant solution!

[@TesserId]

Have to chuckle at the prominence/ubiquity of Digikey. They certainly have become the availability standard for electronic parts. I think I even used them back when I worked at Radio Shack after school.

[@henkvanderwath4405]

This is such an amazing project and could seriously reduce fires in a lab from unattended experiments.

[@chain3519]

Love this community you've cultivated over the years (nearly a decade?)

[@AlphaPhoenixChannel]

this is awesome! with your current construction, what do you see as a limit for the bar temperature? any critical components that don't come in a high-temp version? I guess if they can survive maybe 120C they should be fine for almost anything on the plate cause it's going to be water based? I wanted to come up with an example of a non-water thing you may want to stir, considered metals, realized you'd want a eutectic, thought "well why not use solder?" then realized I'm an idiot... =)

[@AppliedScience]

Thanks! The commercial IC's are rated to 85*C, but automotive versions are good to 125*C. The magnets are neodymium in this unit, but would probably need to be replaced with something with a higher curie temperature. The urethane overmolding is not suitable at all, and should really be PTFE or PFA, ideally. It would be an interesting case study to find out what range of temperatures would cover 50% (or whatever) of the hotplate market. I would guess most would be water-based, but I actually don't know. I think going above 125*C would be a challenge, but there is some precedent: electronics at the tip of an oil-drilling rig! It gets super hot down there, and they routinely replace electronics each time the drill is pulled up to the surface because it is beyond the microcontroller's limit.

[@VEC7ORlt]

@@AppliedScience Not sure about low power stuff, but big transistors in all metal case specify crystal temps up to 200 or so degrees, whilst plastic ones go to 125-150, my guess its package limited, so 200 degrees should be doable, just not with off the shelf parts.

[@skylerlehmkuhl135]

A beaker with a captive stir bar sounds great, but would be a huge pain to clean.

[@BackYardScience2000]

Indeed. Imagine getting organic sludge down in there and not being able to get it back out. 😬

[@brian2k1]

this is much needed! I do wildlife rehabilitation and use a magnetic stirrer to mix the formula gently. thank you for thinking of this and sharing!

[@rndbits8276]

These are the sort of videos that I wish I could 'like' more than once. Brilliant stuff!

[@wouldntyaliktono]

Not quite the same, but I did see a pill-shaped gadget with its center of buoyancy and mass tuned in such a way that it would pivot as the density of the liquid changed. It had a little IC onboard that would use the angle of flotation as a proxy for liquid density around a very narrow range. Useful as a non-contact means of tracking how far along your beer fermenter is.

[@KallePihlajasaari]

Thank you for open sourcing the idle IP. I wish to live in a world where we all do this.

[@rustyosgood5667]

Just a thought... First of all, excellent stuff as always. If the temp sensor is in direct communication at all times, it could be better to just use an on/off heating scheme depending on the energy to mass ratio. I say this because we once developed an induction heating process (instant on/off with very high energy to thermal mass ratio) that used a laser temp sensor input and our pic controller simply turned on the power until the object/liquid was at temperature. In this way, the feedback was instantaneous and as precise (even with an offset) as possible...much faster and more accurate than a PID. It was even more energy efficient because the calculation time was very close to zero. We used a 1Kw induction power supply to heat a small (25mm^2) susceptor to 300C in less than a second with less than a degree of overshoot....and held it there indefinitely.

[@gregfeneis609]

Very interesting. Another thought about the tx coil going between the mica heater and ceramic plate would be about thermal conduction properties. I imagine they made the heater have nearly the same XY area as the ceramic plate for maximum heat transfer. If the coil went between the heater and the ceramic plate, it would likely take more time to heat the fluid to its temperature. The coil would likely have to endure even more thermal punishment

[@schrodingerscat1863]

This is such a good idea, you could literally halve the size of that stir bar if you worked with the chipset manufacturer to wire bond the chips directly to a much smaller and thinner PCB that way it would be quite easy to get this to normal stir bar dimensions. For a prototype its pretty good.

[@jdbrinton]

Ha! I remember you telling me about this idea so many years ago! So glad you built it :)

[@TickyTack23]

I don't even have to watch this to know I'm in for another awesome project.

[@freehat2722]

Really great work. Thanks for leaving it open source. That's a great gift to us all.

[@leenurG]

Applied Science never will be replaced with GPT of any future versions. 💪

[@jd3330]

We used these bars pretty often and it’s not like putting a thermometer in there is a hassle but this just seems like a super cool concept lol

[@Zewwy_ca]

You make great video's. Amazing to see you open source all your hard work. Truely inspirational.

[@ParsMaker]

this is truly useful equipment to have in a lab, for sure it has potential for marketing

[@boomfiziks]

I’m a high school chemistry teacher. This is ingenious! I would love to learn more.

[@benbionic]

You can get temp sensor RFID tags that are designed for implants. It's much smaller, and cheaper.

[@dubravkohubak5387]

For the heat resistant coil, you can coat the wire with high temperature paint from hardware store. Bake at 200°C for 30min and coil it up. Works good on custom heater cartridges up to 800°C.

[@chrisdickens4862]

I’m a simple man. I see a new Applied Science video, I hit like. Thank you!

[@ITpanda]

This is awesome! If you setup a store and have a third party manufacturer produce the stir bars and hot plate, you would make a decent sum but more importantly would make this accessible.

[@satchell78]

Thanks To calculate the values of an inductor and capacitor for a resonant frequency of 134.7 kHz, you can use the following formula: f = 1 / (2 * pi * sqrt(L * C)) Where: f = resonant frequency in Hertz (Hz) pi = mathematical constant (approximately 3.14159) L = inductance in Henry (H) C = capacitance in Farad (F) To solve for L and C for a given resonant frequency of 134.7 kHz, you need to rearrange the formula and solve for L or C, depending on which value is known or desired: For inductance L: L = 1 / (4 * pi^2 * f^2 * C) For capacitance C: C = 1 / (4 * pi^2 * f^2 * L) Assuming a target capacitance of 1 nF, we can solve for the required inductance: L = 1 / (4 * pi^2 * f^2 * C) L = 1 / (4 * pi^2 * (134.7 kHz)^2 * 1 nF) L = 89.44 uH (microhenries) Therefore, for a resonant frequency of 134.7 kHz and a capacitance of 1 nF, an inductor of 89.44 uH would be required.

[@AgentPothead]

This is awesome and you are awesome for open sourcing it. The only downside I see is the dev board doesn't seem to be available anymore, and the TMS37157 themself are end of life.

[@LFTRnow]

That was indeed interesting, but I have a quick tip for those wanting to measure temperature without anything inside the flask. Try an IR thermometer. They are under $20 and typically read within 5C or less of error of what the actual temperature inside the flask is. Usually you can just aim it near the bottom/middle where there is still lots of liquid inside, but not so close to the bottom that it picks up the heating element. This is not better than what AS is suggesting, but it is quick, cheap and "off the shelf", and you probably already have an IR thermometer or two.

[@tardigrades3184]

The inductor as the coil is genius!

[@mxlje]

"I was pretty proud of that" yeah, you should be! Great video as usual, it’s always a good day when you upload. Thanks!

[@thedude7319]

Why have improvements always be made by outsiders ? A great thing you are making it open source!

[@jayceedee5807]

This just reminded me of an idea I had recently. I learned that human core body temperature varies up to half a degree throughout the day and is linked to the sleep schedule, at peak hot we're most aware, and at peak cold we're most tired. I had the idea to build a measuring device and log it over a while, maybe an interesting video idea for you, seems right up your wheelhouse.

[@thirdeye4654]

Do you suggest using this thing as a suppository for measuring body temp over night?

[@jayceedee5807]

You have a dirty mind.

[@Stefan_Kawalec]

That's what you call the innovation. Excellent idea.

[@randomergy683]

One of the coolest videos I've seen on your channel. And I've been watching your content for a loooooong time. Awesome job (:

[@simon_far]

Love seeing the NileRed beaker pop up on so many channels

[@Ny_babs]

Omg I would buy this right now... I have a habit of putting 2 beakers on the hotplate when I need hot solvent, but I could just use a different stir bar. This is amazing

[@MrNoobed]

I'm glad you didn't just come up with this idea but you even nailed down a bunch of the obvious ideas and preferred implementation stuff so it can't get pirated by lawyers.

[@R-Tex.]

You make such amazing projects! Love your channel. I've been into optics lately and i was researching about building a DIY compound optical microscope (and maybe also implement some optical augmentation techniques like phase contrast, dark field/bright field, differential interference etc.). All i found on KZbin and instructables was single lens (laser pointer/CD burner lens) basic microscopes, a concept I've already implemented a long time ago. I'd love to see you do anything in this direction because i feel like you're the best person to do it!

[@BrennanSedivy]

I read the title and said “holy shit” out loud. This is an AMAZING idea!!!

[@noisytim]

I give it two months, until someone proudly announces this as their "industry-leading innovation, ushering in a new generation of lab equipment".

[@Toastmaster_5000]

Such an obvious product to make, kudos to you for figuring it out.

[@brentc.6690]

Really nice job! However, I believe traditional thermometers will retain one advantage over this stir bar design, i.e., a quick response time. I would be interested to see how the mass of the stir bar and the insulating nature its inert shell contribute to thermal lag. Also, the stir bar sits low and near the heat source of the hot plate. That can cause your temperature readings to be slightly high.

[@quarteratom]

Cool idea, well tested, worked up, with many possible features.

[@monkeytoes90]

I've done some plant tissue culture, and having a temp and PH sensor in the stir bar would REALLY improve workflow on media prep.

[@iq911506]

This is a very interesting concept. Something to consider if attempting to use this at higher temperatures is the change in impedance of your coil altering the tuning. I'm not great with RF and only experienced with 13.56MHz so this may be a non issue.

[@cajampa]

Please when this is available to buy somewhere let us know. This is an epic idea. Soooo much better than using a probe. I hope some kits can be produced for some popular stir hotplates.

[@Theyesac18]

Haven't even watched the video yet, but I already know I absolutely need a set of these asap, preferably made with ptfe. Dont even care about the price point, we need about 8 in our lab. Set up a store page and we will buy.

[@BackYardScience2000]

Same. I'd take 5 of them, right now.

[@btasler]

When I am trying out a new idea, I will often spin up a 'sloppy' board with extra test points and such. These aren't ugly by any means, and they aren't necessarily intended to be final products. Instead, these are merely proof of concepts which get me so I can start writing code. Another benefit of these hasty boards is that I have a baseline- basically, what do I hate about it. Generally speaking, for me it is an iterative process- the second board is always more refined then the first, etc. If I carry an idea all the way through, by the third iteration it is usually pretty close to what I want the final product to be including final packaging. The thing that I find is that it is generally less desirable to show people those initial/incremental concept boards because most people can't see past the bodges and conclude an inferior idea. In other words, I can fully wrap my brain around your base- obviously if you cultivated it further you would roll your own boards and the innards would be much sexier, but I think it is a terrific idea and one that has quite a bit of potential. I can (easily) get past wall warts and dev boards and hot snot, but the people I show my electronics to generally can't.

[@reefdiver200ft]

I sure hope that you patented this concept. This is very saleable product.

[@JowSithm]

You could probably make an absolute mint selling this tech to the restaurant industry.

[@MrJeppeholt]

I'm wondering if it's possible to create a thin mat on the outside of the ceramic that contains the coil, allowing you to use the device without having to modify the stir plate. Essentially, it's an add-on that you can use on any existing plate.

[@user-ko7lz3kr1d]

You'd still need to modify the electronics for temperature control, no? Or could you just plug it in to the port that the thermocouple usually is plugged into..?

[@svampebob007]

@@user-ko7lz3kr1d If you go a level above basic hotplate you should get a "controller port", I think a company that sells modified plates could be viable for the amateur/newbie market, but if you really wanted to breakthrough the prosumer/industrial market you'd have to partner up with recognized brands. I showed this to my dad that works for one of the largest Agrochemical company in Latin America in R&D, and he was thoroughly impressed, he also worked as a Uni Professor, and said basically what I was thinking: "This is really great it would be really good for students and amateurs to get into chemistry making their lives much easier we have it here in the lab, the equipment that we use here is highly specialized but sometimes more complicated then needed and dated in terms of what is possible. I could see myself using this as a student and when I started my career, I don't think this is coming into major R&D labs anytime soon, but it wouldn't surprise me if new labs just starting out would implement newer and simpler technology into their workflow. This is great and I'd love to build one with different probes and try it out with my colleges!" (paraphrasing he only speaks Spanish and French) I love the idea and I hope that I can make one for my dad with different probes this summer, I'll try to ship it to him from Northern Norway 🤞😁🤞 Mostly to test out the claims of "express over night shipping anywhere in the world" they claim up to 3 days door to door delivery, last time we sent a standard package (one single book) it took 47 days to get to here.

[@MrJeppeholt]

@@user-ko7lz3kr1d Yes, you're right. The electronics for temperature control would still need to be modified to work with the RFID tag. However, having the ability to use this add-on on any existing stir plate would be incredibly convenient and cost-effective, especially for laboratories that have multiple stir plates. Plus, with the mat on the outside of the ceramic, there would be no need to worry about potentially damaging the stir plate during the modification process. Overall, this would be a great solution for labs looking to upgrade their temperature monitoring capabilities without having to purchase entirely new equipment.

[@randombloke82]

If you already have plates that are set up to use a thermocouple probe (like the second unit briefly shown in this video) you could store the coil/bar electronics in an exterior module that interfaces with the plate unit via the probe connection. Less advanced features but effectively plug and play for temperature.

[@rainwater397]

That is absolutely genius. That should be standard equipment

[@kevinreardon2558]

Unbelievably fascinating. Invention for invention's sake (like research for research sake).

[@etmax1]

Excellent implementation, you can improve the range of this stuff by placing ferrite sheet between the coil and the stir bar which dramatically drops the temperature it's exposed to. They can charge cars at about 30-40cm so there's a lot of scope there. Thanks for the pointer on the ceramic coated wire, that has a lot options for me on other projects.

[@brocktechnology]

Seems like such a good idea, I would have liked more about why your group decided not further pursue commercializing it.

[@reddcube]

Even without a fancy stir bar, an RFID sticker on the flask could be useful. Use the tag for inventor management or process control.

[@tsraikage]

well, right when i thought i wouldn't be able to admire him more, here he goes. fantastic video, concept, execution and cherry on top, the open source.

[@LReBe7]

Forget about using the stir bar to keep data on what the beaker has been doing! This stir bar can be used as a sample label and data logger, eliminating the need for a lot of written notes. Also: if you get to data log the viscosity, pH, pressure and temperature (and the PID control loop output over time), you can get a shit ton of insight into your reactions and even use the extra parameters as a feedback signal for automating the reaction control loop.

[@-Kerstin]

It's cool that there is a way to make this work at all.

[@markpinther9296]

He takes over the entire stirring unit… of course you did! We’d expect nothing less. hahaha! Nice work

[@bariumselenided5152]

How is this not already a thing??? But bravo, this needs to exisy

[@krashanb5767]

You are awesome. Cool invention and a great explanation how everything works.

[@4n2earth22]

I need to remember to put my welding goggles on before watching your vids, Ben. Brilliant, in so many ways. Great Ideas!

[@tissuepaper9962]

Thank you for reminding me that "brilliant" meaning "intelligent" is a metaphor.

[@dquad]

Looks like a fun project, thanks for sharing it with us Ben.

[@calebcarroll8348]

You're a genius and you've taught me so many things thank you!