# DIY Peristaltic pump?



## majstor76

Its tricky to make peristaltic pump in DIY and they are cheap so people does not want to bother with DIY. But i think that case could be made on cnc (im operator of one). For material i would use kerrock or max compact


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## mistergreen

They are cheap? do you have a link? 

I was thinking last night and I guess I can make the body out of a chunk of wood. The circular hole can be drilled with a hole bit and then the face can be covered with a sheet of plexiglass/acrylic.


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## mistergreen

For this application, it would be a liquid fertilizer delivery device. With a servo or stepper motor, you can change the speed so you can control the amount. 

I'm choosing a servo because it's a bit easier/cheaper to control.


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## Wasserpest

I tried a couple using a mechanical timer as the motor, for one complete rotation per day. In the end I gave up because it was tricky to exert enough pull/push to get the tubing pinched closed, but not too much to overwhelm the timer. Plus it wasn't very adjustable, just enough for adding concentrated micros to a smallish tank.

You need a little high-torque motor. This is where the cost side comes in... good if you have access to them. If not, I'd agree with majstor... might be more cost effective to go with the relatively inexpensive APT pumps.

Here's something to get your creative DIY juices flowing...


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## MlDukes

The timer idea is clever.

If anythign rig up a simple unit not worrying about flow rate just consistency - then you can calculate how much is pumped per min/hr and in turn use a timer to control how long it runs each day.


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## mistergreen

haha, that autodoser is cool.

Yeah, I worry about the fudging to get it pumping too. A good stepper motor has enough torque. It's around $15... But the controller for it would be around $30. I'll have to compare a servo's torque.

5.2-6.5kg*cm is good torque right?


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## majstor76

You can seach on ebay for "dosing pump". Currently there are 6V/12V 50-100 ml/min mini peristaltic pumps for 30$ onwards. There are also medical pumps with digital controls, pumps for detergents for washing machines etc... I have just ordered one mini pump for 30$ to see how it works. It is just a peristaltic head with little motor


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## mistergreen

Thanks,
I think I can build a bump and a controller for ~$35..... That's pretty much the price of a pump alone. 

Now we'll see if I have time to make it 
If it fails, I can always use the motor to make a RC car or something! I'm thinking about buying the lego mindstorm for 'educational' purpose.


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## DarkCobra

How about a reciprocating/plunger style pump?

There's one shown on the page Wasserpest linked.

Use a syringe as the pump. Connect the nozzle to the center of a standard airline tee. Connect the two ends of the tee to the reservoir and aquarium via two check valves, so that solution always flows the proper way when the syringe's plunger is actuated.

You just need to pull, then push, the plunger.

If a mechanical timer doesn't suit or isn't strong enough, use a good servo. That would allow you to program in any dosage.

Or use any gearmotor with sufficient force, like a <$10 cordless screwdriver. Just like the horn on a servo, attach a disc to it, with a rigid mechanical linkage from the plunger to an off-center hole in the disc. There's no need to reverse the motor, which simplifies drive; all you need to do is turn the disc through one full rotation. A full rotation can be sensed with a microswitch that detects a protrusion or cutout on the disc. Dosage can be adjusted by the throw of the linkage, number of full rotations, and concentration of the solution. Just one digital input and one digital output (with a drive transistor) on an MCU for this. Easy.

With a little shopping around for inexpensive gearmotors, I'd think this could be built for $15/pump.


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## mistergreen

So I went ahead and started building one.


























It's being controlled by my little arduino for now. It's kinda works but it should work better if I get another less rigid hose. I'm using a silicon hose but I think a latex hose would be better.

Does anybody know where to get a 1/4" latex hose besides online?
I might have to buy some online. I can't find it anywhere.


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## jeremyblevins

Home depot and lowes have it around me.


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## mistergreen

yeah, they have 1/2" hoses. Nothing smaller.


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## jeremyblevins

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?jspStoreDir=hdus&catalogId=10053&productId=100183224&navFlow=3&keyword=latex+tubing&langId=-1&searchRedirect=latex+tubing&storeId=10051&endecaDataBean=com.homedepot.sa.el.wc.integration.endeca.EndecaDataBean%40417ff506&ddkey=Search


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## mistergreen

nice! But not available in my city!


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## mistergreen

Just found a rubber company that sells latex hoses in my city. I'll have to call them on monday to see if they can sell me some from their warehouse.


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## mordalphus

http://www.home.zonnet.nl/rsetteur/aquarium/karel/doseer_pmp/index_doseer.htm


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## mistergreen

^^^Wasser already linked that.


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## mordalphus

Ahh, so you just wanted go a more expensive and difficult route? lol


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## mistergreen

Difficult but I have the resources and it's not expensive. It's much prettier too.


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## Wasserpest

Looking great, I love it. Reminds me of things going through my head back then, but I never got the casing made.

For hoses, most peristaltic pumps use Norprene or Santoprene hoses which are easily compressed, but regain their shape. I think APT sells Norprene in bulk, Santoprene comes with the Aquamedic pumps. There are probably cheaper sources out there.

How fast does the motor spin? If you can make it slow enough so it's controllable with a simple minute-timer (say 1 or 5 ml/min) and the motor is relatively inexpensive I bet you could sell a lot of them here and there.


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## mistergreen

Thanks for the heads up on the tubing. I'll try the latex tubes first. It's only $1 for 2 feet.

The motor (a 360° continuous spin servo) spins at 1r/s with good torque. Some servos can only spin within a degree range. A neat thing with servo is it's bidirectional and you can control the speed.

And I was playing with the speed earlier while I'm waiting what to do with the tubing issue.




















The black knob or potentiometer for you tech guys controls the speed of the motor. The knob isn't the greatest. I can only get 3 speeds out of it, the slowest being .1 r/s.


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## mistergreen

Well, *SUCCESS!*


















So, the prototype is built, now to build 3-4 more when I have time.

$19 to build one.
(1 servo, 2 bearings, plywood, acrylic sheet, 3/16 ID latex tube)

19 x 3 = $57

and then I'll have to buy a servo controller for $20.
http://www.sparkfun.com/commerce/product_info.php?products_id=9664

This controller has 6 channels so I can hook up to 6 servos to it if I want. It's also programable so I can have my wasser-controller turn this on and it'll do its logic to pump out X amount of fertilizer and then turns off.


Actually, do you think it's better if I build knobs (potentiometer) to control the flow rate rather than have software do it?
It's not that hard with this controller.


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## Wasserpest

Very nice! If you ever make more of those I'd be interested.

I think a poti to adjust the flow rate would be better for general use. Would it be possible to skip the controller and run it on a minute timer? Or do you need it to adjust the rotational speed of the servo?

It would be sweet if $19 + a timer = $25 would be all that's needed. You could sell them as DIY kits.

See how much it backflows by placing the inlet 3 or 4 ft below the outlet and leave it there for a day or two.


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## mountaindew

Well done!
Nice diy design.


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## mistergreen

Wasserpest said:


> Very nice! If you ever make more of those I'd be interested.
> 
> I think a poti to adjust the flow rate would be better for general use. Would it be possible to skip the controller and run it on a minute timer? Or do you need it to adjust the rotational speed of the servo?
> 
> It would be sweet if $19 + a timer = $25 would be all that's needed. You could sell them as DIY kits.
> 
> See how much it backflows by placing the inlet 3 or 4 ft below the outlet and leave it there for a day or two.



Yeah, the driver is needed to tell it what speed and direction to go. A cheap alternative to an expensive slow motor in a APT peristaltic. And it's more versatile since you can control the speed instead of a fix speed.

Do you know if the APT peristaltic needs a driver as well or is it plug-n-play device?

Now that I know it works, I can fine tune it more like get slightly taller bearings to make better contact with the latex tubing. I'm using found bearings with this prototype. I'm sure there would be some sort of backflow.


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## ReefkprZ

try pumping uphill as far as you can then shut it off to check how much back flow there is. you may only need a mm or two larger bearing, if you go too large on the bearing you would probably cause undue wear on your tubing and armatures or servo


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## mistergreen

ReefkprZ said:


> try pumping uphill as far as you can then shut it off to check how much back flow there is. you may only need a mm or two larger bearing, if you go too large on the bearing you would probably cause undue wear on your tubing and armatures or servo


Yeah, we're talking about a few millimeters but it'll make all the difference. The bearings are being held on with super glue  It was a pain to adjust to make it work but knowing is half the battle.

I'll go ahead and test my prototype for backflow just for the heck of it.

Oh, Just thought of another benefit for the servo driver... You'll probably want more than one of these pumps anyway (One for KNO3, one for K2HPO4, one for micros)... A timer can turn all 3 servo at once but they'll start pumping at different times so the ferts won't readily mix and react. You just need one outlet for this.


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## Wasserpest

The APT pumps are plug'n'play, the cheapest SP100 come with fixed speed (several speeds to choose from). They have adjustable ones too.


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## ReefkprZ

mistergreen said:


> I'll go ahead and test my prototype for backflow just for the heck of it.


I was curious how snug it was before you mentioned the superglue now I am dying to know LOL


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## mistergreen

It's a really snug fit but I think the bearing is too small (3/16 height) and the latex tubing is too big (3/16 ID)... Backflow is pretty fast when the pump is not running.

I'll have to get a 4/16-5/16 bearing and a 2/16 ID tubing.


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## Jace

mistergreen said:


> Well, *SUCCESS!*
> 
> and then I'll have to buy a servo controller for $20.
> http://www.sparkfun.com/commerce/product_info.php?products_id=9664
> 
> This controller has 6 channels so I can hook up to 6 servos to it if I want. It's also programable so I can have my wasser-controller turn this on and it'll do its logic to pump out X amount of fertilizer and then turns off.
> 
> 
> Actually, do you think it's better if I build knobs (potentiometer) to control the flow rate rather than have software do it?
> It's not that hard with this controller.


I would have the controller operate the servos. Honestly if you have pots on there it would take fine tuning and if you can only get 3 speeds right now, I wouldn't worry about it. With that controller if you ever upgrade your tank or need to adjust the flow you can just unplug it and update the software on it. 

By the way, can you send me pictures or a description on how you made the top part for the pump? I see in the final pic you layered it in what looks like a thin piece of wood, looks nice. I have no background in mechanical stuff though.


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## zavikan

It feels odd pushing my own product....but in all honesty, I'm pretty proud of it. 

http://www.plantedtank.net/forums/equipment/95997-ive-gone-peristaltic-pics-explanation-inside.html

How to have a 7 day fully programable industrial strength peristaltic pump autodoser for less then $80. I'm sure you could pick up the parts for cheaper then I did by shopping around. 

Go find the beat to old industrial washing machine being junked by a laundromat. These little pumps are designed to be used alot (unlike the cheap aquarium ones that cost $90), just replace the tubing.


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## mistergreen

Yeah, I saw your thread.... It is pretty cool but the chance of me finding the pumps isn't very good.


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## jpguppy

Any updates on this? I have been considering building a peristaltic myself arduino controlled for auto top-off on my saltwater tank or for chemical dosing. Also, do you have a list of items that you bought and where?


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## mistergreen

You should go ahead and think about making your own peristaltic... I put in new parts tonight and testing back flow right now and I'm getting 2 drops of water per second out of the pump... Looks like the water is holding. Will post pictures tomorrow...

jpguppy, post your auto top-off!


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## MrMoneybags

liquid autodosers have been brought up before...

...heres teh most reasonable/best suggestion/solution Ive found

check post #27

http://www.aquaticplantcentral.com/...59729-diy-liquid-auto-doser-3.html#post486616


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## mistergreen

Ok, I had a question from somebody on how I attached the bearings onto the wheel... 
This is how I did it.









connecting parts for 'strux' Lego thingy....









those get cut up with a hack saw and they fit perfectly into a 1/4" hole of the new bearing... I believe it's a 4/16" or 9/32" height bearing.

They get glued on and sanded down until they fit correctly.









The benefit with super glue is it's strong but if you make a mistake or the bearing isn't sealing the tube correctly, you can snap it off and redo.










Here it is off, full of water, and I made sure to turn it off where only ONE bearing is in full contact with the tubing. This is to test if only one bearing is good enough to keep the water in the system and not have it back flow. The latex tube is 1/8" ID and is super glued onto the wood. The positioning is pretty important: not too high or low, right in the middle within the circular casing.

It looks like this is working great.. If I take off the acrylic face plate, the servo would run smoother since, it's pushing back on the tubing as it gets squished by the bearing and that increases the friction but it's good enough.


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## mistergreen

Place to buy bearing:

http://www.vxb.com/page/bearings/PROD/1-4inch/R4AZZ


Place to buy the servo:
http://www.sparkfun.com/products/9347

Arduino code for the servo


Code:


#include <Servo.h>

Servo myservo;

void setup()
{
  myservo.attach(9); //set up the servo as usual
}

void loop() {
   // on this servo 1500 is stopped, above 1500 is clockwise, below is counter clockwise... 2000 is max I think
   myservo.writeMicroseconds(2000);
   delay(15);
}


leave out the delay if you want it to spin a little faster.


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## the register

mistergreen, just want to let you know this is really awesome, thanks for sharing this.

I'm personally in between tanks (during my summer move I lost all of a 100 gallon reef due to a car breaking down...) but am thinking about getting back into things with a planted tank. Seeing this thread got me really excited about setting it up so that I can have a reason to hack on arduino / electronics. It's been a couple years since I've done some embedded system work (meaning back in college), but fish tanks + diy electronics sounds like a damn good time.

If/when I put one of these together I fully intend on giving you credit.

I wonder if you could somehow get sparkfun to put together a kit for this (maybe even get you a kickback).

p.s. nice work on the wood / acrylic, could we get a shot from the side (trying to visualize how big the servo is)


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## mistergreen

Thanks,
I haven't had the change to finish this. I've gotten the servo controller but will need a windows machine to program it 

I'm using my arduino for my diy par meter at the moment.

Here's the back









The guys at the sparkfun forum are helpful as well. Some might be in the aquarium hobby too.


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## majstor76

I was dismantling one old Epson CX40 inkjet printer and noticed that it has 2 DC motors with lots of various gears witch can be used for dIY peristaltic. But , most interesting is something that looks like mini peristaltic head. Silicone tube goes thought it and it is used to suck all excess ink that drips out of ink cartridge when in parking spot and transfer it to compartment on bottom of printer. That compartment is filled with something like cotton to hold ink.

Im gonna check it a little bit , maybe it can be used for our purposes. I dont really need peristaltic, i have 2 and one more is coming but curiosity has killed a cat, not man 

Inkjet printer can be all one needs for building diy peristaltic: head, power source, gears, maybe even control if one is into electronics

EDIT: i tested it and its working, kind of. Problem is motor which is servo and it needs some kind of driver. I need just a plain DC 12V motor


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## Jace

http://img171.imageshack.us/i/kinkg.jpg/

Hey, almost done with your build, but I'm running into a problem where I am not getting any suction. Is it because the tubing is kinking when the bearings are rotating?


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## mistergreen

I used super glue to glue the tube to the sides of the casing.


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