DIY Stirrer

Here’s my attempt at DIY’ing a stirrer to keep my alk, calc and mag properly mixed in their containers.

I got the idea on line, what was done was someone took a computer fan and attached magnets to it and when applying power to the fan it transferred the motion to the stir bar via magnetic field.

Since I had 3 of these fans lying around I thought that I would attempt the project.

I have a bunch of these little earth magnets, I fear that they will be too small to achieve what I want though, we’ll see.


The fan with the stir stick on it.


I glued the magnets to the fan, they rest right on the edge of the inner hub of the fan.

I ended up attaching 2 magnets to each side, north up on one side and south up on the other

This is an old cell phone charger that I found in a box, I clipped the connector off the wire and exposed the 2 power wired.




Now that it’s all set up I put the fan underneath a flat furface.


Cup of water directly over top.


Dropped the stir magnet in.


And here’s a video of my first attempt


Still have a ways to go but there you have it so far. Any helpful guidance is welcomed.

"this video is private" it looks like it could work, although I would like to see.....

That looks pretty cool, how did you thinik of that? Are you an electronic genius? I'd like to see what you come up with when trying to control the speed of the motor. I don't think that using a variable resistor will work.

A rheostat switch is pretty easy to wire in. I have seen them used for motors before.

shortbus wrote:That looks pretty cool, how did you thinik of that? Are you an electronic genius? I'd like to see what you come up with when trying to control the speed of the motor. I don't think that using a variable resistor will work.

I can never make out if you are being serious with your questions or not. If you read the first post, I got the idea of using magnets and a computer fan from a home brewing forum that people were using this technique to stir in the yeast, (not 100% what that process entails in the beer making hobby) but using this instead of an actual stirrer is a lot d more fun and cheaper.

dwolson2 wrote:A rheostat switch is pretty easy to wire in. I have seen them used for motors before.

You're right, you can use a potentiometer (pot or variable resistor) to control motor output, but depending on the current flow you will create heat via the resistant quality of the pot, so the wattage of the pot has to be fairly high when used to run a motor 24/7. So what I intend to do is instead of converting that energy to heat via the variable resistor, I will use an IC (more specific a trigger inverter) coupled with diodes, transistor and capacitors to store the energy and use it via a pulse varying the pulse using a smaller pot, that way the energy isn’t wasted into heat. It's a fairly simple circuit, I was going to draw it out today at lunch, because I'm a visual person I need to see the flow of current to make sure it'll work before I attempt to build it.

I doubt that I will be able to use a rheostat in this circuit, I’m going to need both ends of the fixed resistor in the pot for continuity. We’ll see.

It’s definitely going to be fun, unless it doesn’t work.

Well here it is,


If someone can critique it to verify it will work, that would be great.

I will label the values of each component later, I need to see what the motor and phone charger are rated at.

I'm not 100% on the integrated circuit, that one in the schematic has 4 triggers but I only really need 2. Really only 1 but the second is to reverse the revers, and if my wiring is backwards I can use a third to reverse it again, by then it would be a very clean signal....

I'm also thinking that the transistor is over kill and not necessary, but because it's going to be running non stop I figured I'd toss it in there, and use one that is robust enough to handle the constant current flow (500-600mA).

Oh on another note, I was able to get bigger earth magnets and I messed with them yesterday. they will definitely do the job. the only problem I found was that the magnet is so powerful that the motor (when energized) can't start to spin because the earth magnets are holding things in place. I don't want to go any more elaborate and wind a start coil to the motor so I may put a spacer between the magnet and the motor windings, easy fix.

Nope, I'm quite serious. So with that circuit can you substitute that motor for LED's? if I understand it you are using the NPN transistor as an electronic swithch to pulse on and off instead of varying voltage?

umm. I think you can, but you will have to remove the red wire that is coming from the phone charger and use the appropereate voltage and amperage (that is dependant on if you choose a parallel or a series circiut) for the particular LED's that you choose to use.

Yes the transistor is receiving the signal (orange wire) to the base and that allows corrent from the motor to continue through the collector out the emmitter (completes the path).

Because it is a pulse of either on or off, the amount of dwell will determine how bright the led is or in my case the speed of the motor, by using the transistor, it's going to be able to turn on and off the circiut on the ground side roughly from 10-7000 times per second (so our eye will only see this as bright or dim led’s or fast or slow motor).

I think that if you use LED's you'll have to parallel the orange wire to miltiple transistors that look just like the right side of the circuit that I drew. you just mirror that many times over depending on the number of LED's that you use.

But lets focus on this first…

ok, hurry up so we can focus on a dimmable led set-up. What's the purpose of C1 and why are the other 2 inputs grounded on the IC? Oh and what does ZD stand for?

Let me say up front, I'm barely a novice at this, it's been a long time since I've done anything like this so my answers may not be 100% accurate, and I'm not sure that this circuit is going to do anything but fry, but that's where the fun lies. My Step dad was a genius when it came to electronics. He taught me quite a bit. But that was easily 19 years ago. I’m quite rusty and I can’t find my books to help me out.

The purpose of C1 is to smooth out the power supply to the logic chip, if it wasn't there the circuit would still work but there might be a glitch that would affect the output power.

As for the grounded inputs, I’m not completely sure why they are, I just know that if they aren’t being used they need to be set to ground or the circuit wont work.

ZD stands for zener diode, it acts the same as a regular diode except it allows current to pass the opposite direction when certain conditions are met, in this case if there is a spike in the supply power it allows it to go to ground instead through the motor.

I have figured out the list of components that I need, so now I will search for the parts and see what I can come up with. I should be able to find everything on mouser website.

here's a video with the new magnets.

Dude you could sell these. Make me one?

I bought enough electron parts to make 2 complete components. just in case I wire something in backwards, I have a replacements on hand.

the parts only cost $7.50 through the site but they charged another $10 to ship them.

It seems that they are all off the shelf parts I bet I could've gotten them from fry's or radio shack.

if it works it would be no problem making you one.

Ok cool

well, instead of waiting until Monday, I went to Fry's today and grabbed everything that I needed. They didn't have the same exact parts that I ordered which isn't a big deal. the whole reason for going there today was to get a blank circuit board because I forgot to order one, but instead I grabbed one of each and headed to the register (BTW ordering online is a lot cheaper even with shipping). After getting home I got started soldering.
First the 14 pin IC socket was soldered on:




Then the 2 capacitors:



The 2 diodes:



The 10K ohm potentiometer and resistor:



The transistor went on next:



Here's the underneath, I still have to solder a bunch of jumper wires but I will do that after dinner:



Once I get it buttoned up and ready I will shoot a video of it either working or burning up... Wish me luck!!!

Looks like I did something right!!! Woo hoo!



Because the voltage from the phone charger was so low, I had to bypass R2 because it wasn't sending enough current to the base of the transistor. A minor miscalculation on my part. however if I want to upgrade to a bigger power source I can do so. And if that's all the headache I got then I'll take it.

Next step is to put a container over the magnets and stir some water for a day to see if anything needs to be heat sinked. I doubt it but I will let it run over night to be sure.

One more in action

Wow, that's awsome. I've seen plenty of these being made but never one using a speed control to throttle the speed..

you can market and sell those if you wanted to.

I had some fun and put food coloring into the jar to see how it mixed...

Here's the actual schematic of what I did

Looks good Jimmy good job. your using that for your dosing right?

Gorgok wrote:you can market and sell those if you wanted to.

Naw,this is something that anyone could do, I just want to make it easier for the ones that want to attempt, to have all the information to do so. I saw plenty of videos of attaching magnets to the motors but nothing about what they used to regulate the motor speed, so I wanted to just clarify it and hopefully make it easier to understand and follow.

clownfish14 wrote:Looks good Jimmy good job. your using that for your dosing right?

Yep, my package came today but UPS didn't leave it at the door. I was hoping to make another one using the proper hex converter to see if it makes any difference by having a smoother control.

I like the idea of doing some engineering with tank components! I would create the same thing but I have no room for my dosing reservoir. I have my alk & calcium in a quart liquid container and fill it up every week.

yeah, I had mine is small 120 ml containers that I had to constantly monitor, I really don't have the room under my tank either, I'm still not sure where these stir plates are gooing to go.

cool project.

Yeah, it turned out to be a lot more work than expected, I really had a hard time trying to find the time to finish it but it's done.



Just as I suspected, it stirred up a lot of debris in the alkalinity container and there was stringy stuff peeling away from the glass and tube.

I'll have to monitor the alk and calc closely over the next week to make sure that I don't overdose. but there you have it....

Dude thats cool! I love the little box you made for them! Great idea!

So are. You going to try to integrate it into your ac3?

I dont see why he would. There is no reason to be able to controll the fans through a controller. Mostly they will be on the same speed

But if he was going to dose at the top of the hour, the fans could come on 5 min before dosing.

no. its going to run 24/7. there's no reasons to have it go through the controller.

dw did you notice that I finally pulled from your play book and frosted the acrylic?

Awesome idea man,

I see that on RC, people are starting to line up to have you make them for them.

Are you going to start selling them?

Thats what i was saying! You could make some big bucks! Come up with a cool name become a sponsor and start selling them!

How much would you charge for 2 single ones?

Or, or.. now stay with me here...just thinking out loud.... what you can do, is go get the stuff and make it yourself.... then you'll have the satisfaction of accomplishing this project yourself...

Lol ya but that takes effort

looking at the scamitic I was woundering what ic chip you used. verry cool project, are oyu going to post the part listing?

sisterlimonpot wrote:no. its going to run 24/7. there's no reasons to have it go through the controller.

dw did you notice that I finally pulled from your play book and frosted the acrylic?

Yup, looks nice

sisterlimonpot wrote:Or, or.. now stay with me here...just thinking out loud.... what you can do, is go get the stuff and make it yourself.... then you'll have the satisfaction of accomplishing this project yourself...

Or you can stop complaining and make a little $, maybe even make it less diy and more production. Mass produce it at a good price. Give people the option of buying it from you or doing it themselves.

Mike, i wanted to use a 74ac14 hex converter but ended up using a 74hc14 instead. it works fine for what I used it for but the ac would have had a clear signal. but the 0.1 hf capacitor handles them both just fine.

if you make one be sure to post it here.

dw,
don't get me wrong, I will make them for club members, as long as you purchase the parts or I can go get the parts and you can pay me back for them. I will make them all day long.

So here it is under the tank. You can see that it is spinning really slow, just enough to keep me happy that things will stay properly mixed as well as not stirring it up too much that the undissolved sediment doesn't get added to the tank.

That turned out pretty good. it looks very clean.

That video puts it into perspective. looks good. you seriously could sell those...

So you have had it in use for a week now, anything to report?

Squeakity Squeak, Squeaker,

Everything seems to be working fine, the alkalinity has allowed the non dissolved solids to be pushed to the side, the calcium on the other hand has some sort of clear/whitish slime in there that has attached to the stirrer, not sure what or where the slime came from, maybe Paul will comment.

I'm waiting for the containers to empty, so that I can give them a good rinsing and see if it continues.

So here's a schematic for using this schmitt trigger to dim leds.



IC1 is a 74AC14 hex inverter
C1-C2 are 0.1 µF capacitors
R1 10K ohm potentiometer
D1-D2 1N914 or 1N4148 will do

The only thing you have to research is the transistor (T1). What ever the driver output for the LED's is you have to make sure the transistor can handle that across the collector and emitter, the base will receive the digital signal from the inverter (5v max). For example if the LED power supply is rated 18v 1.2amps the transistor has to be able to constantly handle that force and current flow. When choosing T1 some transistors will have peak ratings labeled in their description make sure you look at constant ratings, going bigger is fine as long as you don't go too big though, because you'll have to compensate for a larger voltage drop. Oh and make sure it is an NPN not a PNP...

I can't 100% guarantee this will work the way it's supposed to, it won't harm the LED's nor the LED's power supply but you may have the lights flicker under certain conditions.

I wont be trying this unless someone has some LED's laying around that they are willing to let me experiment with, otherwise have fun on your own...

You can also go a bit more in depth and utilize 2 more inputs and outputs of the hex inverter and use it to control another set of LED's such as one controlling the white lights and the other controlling the blues that way you can fine tune the color you want.

When I have time I will draw that one up as well.