First of all, apologise if this isnt the right thread but im sure that it can help alot of DIY ejuicers!
Im DIY-ing a magnetic stirrer to blend my juices & let them chill whilst spinning.
Items i purchased are - a
- 240 ->12V 3amp voltage regulator (DC)
- 6 12v 0.3amp PC fans with max rpm of 2000
- 6 potentiameters (500k ohm) <- 500k ohm doesnt work well what ohm should i use to better control the fan speed?
- Plastic sheets (to hold everything together)
Now its question time! If i set up my circuit as this picture below http://www.resistorguide.com/pictures/LED-resistor-parallel-circuit.png
R = my potentiameters, Triangle = my pc fans.
Will my fan speeds be controlled individually? or did i screw it up... im not too sure and couldnt find the right answer googling.. Also what Ohm potentiameter should i use?
Help is much appreciated! Will post up pics of it when im done!
** Edit - It works!! Will upload pics & show u guys how i did it! My progress pics Diy ejuice stirrer http://iob.imgur.com/uYGg/BePHM8KGny
Edit #2 HALPPP just swapped all the 500k ohm pots to 5k pots. Lol they took turns burning out. need help choosing a potentiameter to control their speeds without it burning out
Each parallel circuit will behave independently of the others, so yes your fans will all operate independently, i.e. each potentiometer will control only one fan by that drawing.
it works! thank you for this! think i got the wrong potentiameters tho... i cant control the speed... it switches off too quickly :/
i got the 500kohms one. what can i change it to? i mainly want to control fan speed!
iirc 10k ohm pots will give you a better control. You're not going to need a ton of resistance. I built one but never used it, the fan motor burned up before I could put it to use. Computer fans aren't designed to spin the extra mass added by magnets.
Also, since you're working on cheap components you're fine, but potentiometers aren't the same as a real pwm setup, so if you get good components, you should look into a microcontroller to run pwm. Also, chop (dremel?) The blades off the fans, a bit less work to spin up, and less resistance from the turbulence.
Came here to say this. Arduino + transistors will give much better speed control
thanks for the tips guys. im a total newbie in electronics (lol just lookat my "pcb" board it was done using bluetack on a blacked cardboard strip... Whats a pwm? yeah im thinking that the next step will be to remove the fans, but i have limited tools and would probably use a really sharp blade to do it or a vape wire (flat head cutter) kinda afraid i may fudge that part up lol
Also whats a arduino lol. ill google these 2 up thanks guys
Edit lol omg. okay i googled arduino. the picture made my brain explode. have no idea where i can find a Pulse Width modulation thingy too
A pulse width modulation thingy is what the board does. Basically, it sends the full voltage, but it turns the voltage on and off really quickly, pulsing it. The longer delays in between the pulses, the slower the fan will turn. The cool thing about it is that you don't have to run your power for the fans through the speed control potentiometers so you don't burn them up. You attach a control pot in one of the pins and it will base the pulse duration on the voltage that the board reads (i.e. if the board registers 50% voltage of the max, you can set it to spend equal amounts of time on and off).
yeah im thinking that the next step will be to remove the fans, but i have limited tools and would probably use a really sharp blade to do it or a vape wire (flat head cutter) kinda afraid i may fudge that part up lol. i have no idea where i can find a Pulse Width modulation thingy too
Was thiking of looking for arts & crafts shops & getting some small hard pieces of plastic or ice cream sticks to glue onto the fan head & attach the magnets on after/if i cut off the fan blades!
Can we build something like this next?
https://youtu.be/DpeJ7UqqkGg?t=102
Group think. Let's do it! Would be nice to be able to do multiple bottles at different sizes too.
haha that looks neat but it isnt spinning fast enough! a mag stirrer will make a whirlpool in your beaker & stuff it full of air bubbles
Since you mentioned finding the right magnets in the imgur link, have you checked out k&j magnetics?
i love the development notes, I pictured a small house cat in a lab coat making this.
You want rare earth magnets. When I built mine I used a 20k ohm pot and it worked ok.
The biggest thing I had issues with was that the fan worked wonderfully with just the magnet, but did not have enough torque to spin in VG. I never did find a high enough torque motor for a decent price and ended up just buying a lab grade mixer.
After having spent around $350 on a heated Fisher stir plate, I now just give my bottles a shake or two and throw them in the back of my sock drawer for a month or so. I found the stir plate to do no better for the way I mix, and the heat to degrade and change the flavor. I suppose I could throw some glitter in an Erlenmeyer flask full of water on it for a geeky Christmas decoration or something, but to me it's a waste for e liquids.
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