Fereidoon Kavosian - 2014-11-15
Here we have a magnetic stirrer hotplate with variable speed and temperature control! This project is a bit more complex than the last one, but don't let that hold you back, one you get started you'll realize that it's really quite easy. For the heating element's voltage controller, I'd recommend using one that can handle twice the wattage of your kettle - mine is about 3000 watts, so I got a 10000W controller to be on the safe side. My digital voltage regulator is an "AC220V 10000W SCR Voltage Electronic Voltage Regulator" that I bought from ebay for about $12. here's a simple overview of how I wired it: MAIN POWER: ----} digital voltage controller ----} heating element ----} Variable voltage adapter ----} 120mm PC fan In the last image, I'd just hot glued the digital control panel and the voltage adaptor together and used an epoxy glue to attach the voltage regulator to the base of the hotplate. I've also hot-glued the base and the hotplate parts together to have a single finished product that's easy to move around and use. Have a fun project and feel free to comment below with any questions!
Awesome. Like you, I like to repurpose things into different things the we're never intended to be used for. Basically a manufactured one is just put in a box with simular components to look nice. Like forged in fire. " Looks are second to performance" I like you just need it to work, I do not care what it really looks like. It is more fun making the tools as well as the use for which you intend it to be used. Great job, keep on brainstorming ideas.
Great... this is what I see and learn. Thank you!
Man 2 years out and I keep coming back to this video. Always wanted to make one but I can not match your awesome skills and smoldering looks :)
This is great however I'm curious about the fan getting to hot. I have components to make this myself but worried about the fan melting. I'll be using either a deep fryer by cutting the aluminum pan down or a coffee maker heating element from my old Bunn maker. I think it will work with higher voltage even though it'd only used for the warmer. Obviously I won't be using the element to heat the water which is busted anyway but more like a water heater element anyway.
I love use Avasva Solutions for that issue.
A recycled kettle, that's brilliant, I have one spare too. Also magnets glued to wire solves the centring issue too.
Personally I'd use a cheap Chinese PID controller for the element control.
hi!!!! nice project juste make my first magnetic stirrer. i was wondering for the heat plate did you add a base (where the fan is) and is if a part of the kettle? thks
Nice,... thanks for posting.
Awesome idea of using a kettle for the job.
Thank you! :)
It is a nice project. I have already tried this. But before final connection I have a question. The raised magnets are at close proximity with concealed heating elements. Is there any possibility to burn the motor or loss of magnetism due to excess heating? I have to run the system more than 2 hours continuously. I am urgently needed your suggestions and help. Thanks.
Hi Fereidoon, can you send me me the actual pic or vid of the wiring? Im planning to make one using a kettle. can you also teach me how to use potentiometer to adjust the speed of the fan or the temperature of the hotplate? I dont know much about the wiring especially for the connections of those variable elements. I always refer to the graphical images and tutorials. Will wait for you reply. Thanks much!
NICE LA
brilliant
That’s genius!!!
Tech Freak Thank you! :D
Cool
I found the digital voltage controller, identical to yours used in the video, it is listed as 220v max.. Will it work with 120 volt systems? the advertisement didn't specify really anything useful.
120v should work 220v is the maximum current the transformer can handle.
Great idea ,and a few upgrades for you which im going to do...You should mount all the controls in a nice control box ,so you dont pull all the wires out when moving it around.im going to use something from the thrift store that works with my controls...the magnets seem a little weak to me so im going to use a neo magnet from a hard drive with more surface area...i see you having trouble with the thermometer ,im going to try a teflon washer with a snug fit so i have control over the height as well as grip by slide adjustment... excellent idea with the bowl effect , ive gone through a few pyrex containers already since i do my experiments outside ..the rapid cooling and heating changes from the hot plate and glass is costly.the water will dispurse the hot and cold temps better.. for sure.im also going to try some various epoxy coats on the neo magnets for stir rod or melt some teflon over the magnets .
can i get schematic
LOVELY PRESENTATION, I HAVE A QUESTION FOR YOU, IF YOU HAVE A MAGNETIC STIRRER HEATER, THE TEMPERATURE IS NOT CORRECT WITH THE THERMOMETER, WHAT DO YOU THINK IS THE PROBLEM AND WHAT CAN I DO TO CORRECT IT. KINDLY SEND TO MY EMAIL ADDRESS, ayooluwagbemi2007@yahoo.co.uk
S.O.L.I.D idea.
Hello Fereidoon,
i really like your video and would like to build one on my own. I have a question regarding the variable voltage adapter. Could you be a little bit more specific about it, please? For me as a beginner with basic knowledge it's hard to find a device similiar to yours. Where did you get that? I live in Germany and things are a little bit different over here sometimes.
Hi Simon,
I'm glad you liked the video. Any generic DC variable voltage adapter will work well. I found this one on amazon.de and it's almost exactly the same as the one that I used in my project: http://www.amazon.de/3-12V-Universal-Netztzeil-1000mA-12Watt/dp/B00ESDII6S/ref=sr_1_15?ie=UTF8&qid=1417864479&sr=8-15&keywords=12V+1000mA
Alternatively if you have an old DC adapter at home that about the right voltage (maybe an old charger or something of that sort) you can connect it to a potentiometer and control the speed of the fan that way. (That's what I did in my other video https://www.youtube.com/watch?v=IwyAbkMMza8)
Good luck with your project and feel free to ask any other questions, I'm a beginner too, but I'm always happy to help! :)
@Fereidoon Kavosian
Thank you very much.
The other problem would be the kettle. I haven't found any that could fit the fan yet and if they do, they consist out of steel.
I came across another interesting way of how to solve the heating issue. Most things that i am going to cook won't go above 100°C/212°F anyway (mainly to produce super saturated solutions. Easier to make seed crystal that way). Instead i would put my beaker into a heat resistant container, fill the container with water and use an immersion heater. Just like a water bath. A 2000W immersion heater can easily handle about 5L of water so i might as well pick a weaker one. It would work fine for as long as i just want to boil my solution.
Yours is of course the elegant one since you can regulate the amount of heat in a simple way.
Simon Janda su
Hello Fereidoon, is it possible to make one of these where the temperature doesn't rise above 89 degrees F? Also, what if I wanted to use something like this to stir/heat a container that could hold 3 gallons of water? How many fans would I need for that if the container was plastic and approximately 15"W x 12"L?
Hi Pamela,
I'd love to help you, but that sounds like it would need a very different design to what I have here, and you seem to need very specific low temperature control.
For such a large volume I would suggest using a stronger motor than a PC fan motor, I would think a desk fan motor (without the fan on it) would be more than adequate. And for heating I'd suggest using several Peltier Thermoelectric units connected in parallel to each other and figure out how much power to feed into it do achieve your desired temperature by just trial and error. You will need several of them to effectively heat such a container, but the overall wattage will be lower than the kettle's so you will have to figure out how much of a load your voltage controller would have to handle based on how many thermoelectric units you use and their power consumption.
You don't actually need any fans, the only reason I used one was for the motor, and in this specific case it also provides some ventilation, which you won't need anyway as the thermoelectric units will cool on one side and heat on the other.
In fact if you were to use a peltier thermoelectric untit, you would be able to heat or cool your container simply by switching the direction of the current that you're feeding through!
I hope that helps :)
RocketmanD12 has made a nice video that may give a decent idea of how to do what I detailed in my previous comment. It's a fairly concise video that would be worth watching: watch?v=pXsOhEdTcqs
@Fereidoon Kavosian Thanks so much for your reply. I think I'm going to see about doing this without the heating element since that is too involved for me. I'm just a dog trainer with an invention in mind trying to put a prototype together--far from the technical wizard you are! I wanted to see if I could make it cheaply at first just to get my idea out there and see if I could find someone to manufacture it working off my prototype. Thanks so much!
I think DC motors get better torque with PWM control instead of variable voltage, available for less than 10 dollars. Search DC motor control, fan control, or PWM control... variable voltage is better for non LED lights
I'll read up up Pulse Width Modulators and figure out what they do, I haven't heard of those before.
I was thinking about using a regular power adapter and a potentiometer, but in the end I decided to go with the variable voltage power adapter just because it offered a clean and easy 2 in 1 solution, and it was cheaper as well, which is something I try to be conscious of when working on a project -- gotta budget my hobbies ;)
I may actually use a motor speed controller for one of my current projects though, so this is definitely a great suggestion to explore further.
Thanks again for your feedback, I appreciate it.
Quick and dirty: modulates between a given voltage and zero. The time interval/frequency is adjusted, lowering the average voltage. The bipolar nature of it is perfect for DC motors and gives them more torque at low RPMs.
As for PWM vs voltage regulation for driving TECs, I've read independent research saying lowpass filtered PWM is the way to go, and then a company proves the opposite mathematically, before pitching their proprietary chip. I found some industrial TEC PID controllers using PWM, but couldn't build it cheap
@***** ty
Erik Persson - 2017-05-01
Amazing! I'm DEFINITELY trying this! So far the best DIY design I've seen on YouTube so far!
Fereidoon Kavosian - 2017-05-03
Thank you so much for your kind words. I feel bad that I haven't made a video in so long. I've done a lot of projects since this one but with school I just haven't gotten around to filming and editing the process :(