Cheap peristaltic / doser pumps investigation

[GlassReef]

I don't have the knowledge to design a PCB but, here is a pic of a breadboard based "connection board" for my 4 stepper motor doser, The pin numbers refer the Arduino Mega 2560 pins and are defined in the sketch - a modified version of Disc1s software. I bought a Solderable PC BreadBoard which allowed me to copy the temp set up exactly. Worked real well.

[theatrus]

Nice drawing - are you using Fritzing? What control scheme are you using for the stepper in the Sketch - half steps, full steps or PWM?

[GlassReef]

Originally Posted by theatrus

Nice drawing - are you using Fritzing? What control scheme are you using for the stepper in the Sketch - half steps, full steps or PWM?

Yes, Fritzing. 1/16 step - setting gives me all kinds of control and makes it very accurate. I played around a little to see how far I could go with the accuracy. I managed to get it to 1/4 ml but, then the problem is how to ensure that your measurements are accurate. I just left the pumps calibrated for 1 ml a minute. If I input 7 ml I get 7 ml. I've tested the calibration from 1 ml to 150 ml. Exact, every time. More than good enough for what we (maybe I) need

Only thing that bothers me is the tubing. The junk that came with the pumps wasn't even the right size! A .1 mm (or so) to small. It allowed air to be sucked into the tubing. Started using the tubing from a Jebao DP-4 I bought but didn't use. Works perfectly but I'm sure it's cheap stuff and won't last long. I've got lots of the beige Norprene 3/16 OD X 1/16 ID but the motors won't cut it. I think I'll be buying hi-torque motors - about 84 oz/inch - that should handle anything.

[theatrus]

Controller boards showed up, no parts yet:

[GlassReef]

That board is so cool (sorry I'm a senior citizen)! Very impressive. Can't wait to see how the doser turns out...

[theatrus]

Assembled board:



The power rails are doing the right thing (5V in, 3.0V out of the switch, loaded down to 4A). The Bluetooth radio comes up. Now to do some basic motor driving

[theatrus]

A few fixups later (need to work on solderability / masks / paste layer for the motor drivers), we have motion:

https://youtu.be/nob_Q3xRC5g

This is 32 microsteps at somewhere near max speed for the motor when microstepping. It can of course go much much much slower (for that continuous tiny alk drip!)

[locke_333]

Nice, that's Something i'd be interested in! i've been looking up these pump for a while but didn't have time to come up with a solution to control them

[psidriven]

bump, any updates? would love to do continuous alk drip

[theatrus]

No updates yet.


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[theatrus]

Some updates (as I dig through my project archive)

- The actual motor driver of the board works great, and the voltage regulation is working out nicely. Smooth and quiet stepper motor control is easy now.
- The RTC circuit was ... screwed up. It also carried over to my lighting controller, so oops. I haven't made a revised PCB without this, but unless you were interested in the Nordic Bluetooth/MCU module, the version with headers works just great. More wiring but everything else fits.
- I should probably make a version which can support an ESP32, but that whole product lineup is kinda a mess right now (everyone is jumping on each other to be the first to market with devboards).

With that said, I can build version 1 PCBs if there is interest, sans the rRF module so you'll need to provide your own MCU. The actual control logic is super simple (set a few mode pins, pulse the step pin however much you want).

[Audi_Guy]

I'm in! Shoot me a PM....

[Fredfish]

Found this looking for something else.

http://www.robotdigg.com/product/103...ristaltic-pump

Looks like a variant of the peristaltic head you found with a nema 17 pancake motor. At $24 the price seems pretty good.

[mannyhernz]

Interested

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[theatrus]

Originally Posted by Fredfish

Found this looking for something else.



http://www.robotdigg.com/product/103...ristaltic-pump



Looks like a variant of the peristaltic head you found with a nema 17 pancake motor. At $24 the price seems pretty good.

That looks nice - the Chinese pump heads aren't bad at all, but always happy to find a more local source. I have a pile of like 20 stepper pumps from eBay now - all the same pump head, some different motors and a wide variety of pre supplied tubing sizes.

Been really busy of late so haven't had time to rev the design or tweak anything

I'm spending some time cleaning up my shop and retooling a few things in the next few weeks so should be able to knock a bunch of things out after that, so I can get updated boards after that point.

[AnnArborJayhawk]

Originally Posted by theatrus

That looks nice - the Chinese pump heads aren't bad at all, but always happy to find a more local source. I have a pile of like 20 stepper pumps from eBay now - all the same pump head, some different motors and a wide variety of pre supplied tubing sizes.

Been really busy of late so haven't had time to rev the design or tweak anything

I'm spending some time cleaning up my shop and retooling a few things in the next few weeks so should be able to knock a bunch of things out after that, so I can get updated boards after that point.

I bought the cheapest 3 pack I could find off aliexpress and used them for an AWC setup from my basement to the tank upstairs with them mounted in the basement, so noise wasn't a concern. Now I'm looking for something a little quieter with more precision for 2 part dosing from underneath the tank where noise matters a little more.

Do you have any preference for one pump over another? There are so many choices on aliexpress and even amazon that it's hard to decide. I figure if you've already looked at a few, even briefly, i'd rather pick one based on your opinion than on nothing at all.

[Synden]

Thank you for this post, very informative, I look forward to more results
I am currently building a 800g NPS anthias system in my basement and plan on using masterflex pumps for my 'critical dosing', but for the continuous feeders and other 'non-critical' pumps, I have been exploring the idea of trying to build my own from various ebay pumps, but the more I looked at them, the more I realized I didn't have a clue as to what would work for my purposes

[theatrus]

Originally Posted by AnnArborJayhawk

I bought the cheapest 3 pack I could find off aliexpress and used them for an AWC setup from my basement to the tank upstairs with them mounted in the basement, so noise wasn't a concern. Now I'm looking for something a little quieter with more precision for 2 part dosing from underneath the tank where noise matters a little more.

Do you have any preference for one pump over another? There are so many choices on aliexpress and even amazon that it's hard to decide. I figure if you've already looked at a few, even briefly, i'd rather pick one based on your opinion than on nothing at all.

I personally like the stepper motor pumps quite a bit. The housing and roller mechanism is actually pretty robust, and they can produce quite a bit of torque. The repeatability of the stepper outweighs any driving challenges (you need a stepper driver) in my mind. In addition, the stepper motor is a standard NEMA sized motor so can be swapped if the drive ever gives out.

I have no idea what brand they are or where they're sourced, but I've gotten the same black housing with the metal latch and the blue center sticker pumps from multiple vendors. Each vendor cobbles in a different piece of tubing, but the motor and housing appear identical. The motor uses a standard 2.5mm JST header, or you can cut the leads since there is plenty of extra wire.

I haven't found the "perfect" tubing for them, but silicon tubing works the best, so I wouldn't use it for continuous duty applications.

[cah1982]

Im tryin to do same use a stepper as a doser, and have written all code for arduino, but just in testing phase at minute, Its not as advanced as yours im just using generic sheilds with A4988 drivers

Did you manage to get accurate dosing? at minute im counting steps to 100ml as a calibration then doing

calibration steps / 100 * how many ML to dose

Just wondered how accurate you found these dose heads and if you ever got to try the BPT tube (thicker wall)

[theatrus]

Originally Posted by cah1982

Im tryin to do same use a stepper as a doser, and have written all code for arduino, but just in testing phase at minute, Its not as advanced as yours im just using generic sheilds with A4988 drivers

Did you manage to get accurate dosing? at minute im counting steps to 100ml as a calibration then doing

calibration steps / 100 * how many ML to dose

Just wondered how accurate you found these dose heads and if you ever got to try the BPT tube (thicker wall)

Yup! It all depends on the pump head - the smaller chinese stepper heads don't like the thicker wall tubing and aren't very good for dealing with higher vacuum (long intake pipes).

If your feed and dispensing tubing and setup is the same, once calibrated its very consistent, much more so than the DC pump motors.

[cah1982]

Cheers, are you saying you tried 3mm inner / 5mm outer bpt pipe in the bellow



from 100ml calibration, 1mm-10mm seamed perfect, but 25ml was out. but this could be down to RPM im using

Going from ebay one site said 50rpm max, produces 160ml,

50rpm certainly doesnt produces 160ml, I ended up running it at 200rpm as i found another site suggesting 300rpm was max