How to push pistons with arduino?

Hello,
I have seen that linear actuators don't go cheap, with a starting price of over 30 euro. I would need to use several of them to push some small pistons.
Is there a way to push pistons in Arduino? If not a linear actuator, some cheaper alternative? The idea is to push different liquids in series, thus pushing the syringe's piston seemed the easiest. Perhaps a small water pump instead of a syringe, if they exist?

Gigiux:
Hello,
I have seen that linear actuators don't go cheap, with a starting price of over 30 euro. I would need to use several of them to push some small pistons.
Is there a way to push pistons in Arduino? If not a linear actuator, some cheaper alternative? The idea is to push different liquids in series, thus pushing the syringe's piston seemed the easiest. Perhaps a small water pump instead of a syringe, if they exist?

You mean for mixing different liquids into one pipe? Why?

Gigiux:
Hello,
I have seen that linear actuators don't go cheap, with a starting price of over 30 euro. I would need to use several of them to push some small pistons.
Is there a way to push pistons in Arduino? If not a linear actuator, some cheaper alternative? The idea is to push different liquids in series, thus pushing the syringe's piston seemed the easiest. Perhaps a small water pump instead of a syringe, if they exist?

A much cheaper alternative is a cam attached to the output shaft of a gear motor. As the cam turns, it pushes the piston.

Paul

It is easy to make your own linear actuator, using any gearmotor (brushed or stepper), a shaft coupler and some threaded rod.

Use the search phrase "diy linear actuator" for examples.

A hobby servo could also be used to push a piston with a connecting rod between the servo arm and the piston.

...R

What sort of force and throw are we talking about?

Peristaltic pumps can be had (or even made) quite cheap and can be good for measured liquid amounts.

They are often used in dispensing projects and low voltage ones are also available

trojanhawrs:
You mean for mixing different liquids into one pipe? Why?

Exactly for the purpose of mixing chemicals. At the moment I am looking at small syringes for insulin (but I am not using insulin), which hold 0.3 mL, the piston is about 5 cm in length and less than 0.5 cm in diameter.

Paul_KD7HB:
A much cheaper alternative is a cam attached to the output shaft of a gear motor. As the cam turns, it pushes the piston.

Can you clarify more on this? Thank you

Robin2:
A hobby servo could also be used to push a piston with a connecting rod between the servo arm and the piston.

...R

I have found these linear servos: https://www.amazon.de/gp/product/B0855PWZQL/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

MarkT:
What sort of force and throw are we talking about?

I don't know how to measure them, but it is not much...

ballscrewbob:
Peristaltic pumps can be had (or even made) quite cheap and can be good for measured liquid amounts. They are often used in dispensing projects

This could dispense the syringes altogether, I have found this https://www.amazon.de/Suchinm-Peristaltikpumpe-Flüssigkeitsperistaltikpumpe-Experimente-Feinchemikalien/dp/B08BHLPB1N/ref=sr_1_7?dchild=1&keywords=micro+peristaltikpumpe&qid=1595007912&sr=8-7
Thank you all!

Gigiux:
Can you clarify more on this? Thank you

Where to start? Do you know what a cam is? Do you know how to attach one to a shaft? Do you know how to make a fixture to hold all this assembly?

Paul

Paul_KD7HB:
Do you know what a cam is? Do you know how to attach one to a shaft? Do you know how to make a fixture to hold all this assembly?

Paul

The answer is no to all questions, sorry. Can we start with the CAM? how do I search for one? Thank you

Google cam wikipedia

...R

there are also some very small very low voltage Peristaltic pumps where dosage could probably be better controlled.

After all a lot of these types of pumps show up in hospital equipment and labs where measurement is more critical.

They do work on a multi cam 1,2,3,4 (or occasionally more). The smaller the pump but with more lobes the finer the control dosage.

Variety and price to suit almost any eventuality.
No direct fluid contact so no need to re-fill syringes
No return mechanism needed so no need to find a spring loaded syringe (if that was ever needed)
Easier to calibrate than a cam on a syringe.
Easy to mount to existing or new configurations.

Not used the really small ones here only the larger ones for cleaning chemical or water treatment systems / dispensers on industrial wash plant.

You may also find them referred to as "roller pumps" but I know them best as Peristaltic.