jremington:
Consider a 1000:1 gear motor. They run on as little as 1 V at about 2 RPM, and perhaps quite a bit less. Or, one such motor could be geared even further down.
Thank you so much for your response jremington. I searched for this kind of motor and I have figured out that the syringe plunger load might cause stalling and damage. On the other hand, as you know these motors should be controlled using voltage which cannot be precise enough for my project (it's hard to control voltage in 0.01 steps). Anyway, I am pleased to consider your recommendation if stepper motors couldn't convince me.
Robin2:
A stepper motor has the advantage of precision. You can specify exactly how much it should move and, by setting the interval between steps, exactly how fast (or slow) it moves regardless of load (assuming, of course that it is sufficiently powerful).If the stepper motor is turning a screw that causes the syringe plunger to move then you are likely to have a very small movement per step, For example an M6 screw has a pitch of 1mm and with a stepper motor that has 200 turns per rev each step would advance the screw by 0.005mm. And with (say) 4 x microstepping that would reduce to 0.00125mm per microstep.
Thank you very much Robin.
First of all, I needed to hear this "it moves regardless of load (assuming, of course that it is sufficiently powerful)."
Secondly, considering your calculations, It seems that I can acquire my desired flow rate with a 1 ml syringe which has 4.69 mm inner diameter.
Flow Rate=0.001254.69^2pi*3600=310.8 ul/h. It is not 100 ul/h but that's precise enough.
Just three more questions if there is no problem:
-Could you please suggest a motor driver to use with Arduino Uno R3 and a 1.8 deg Stepper Motor? Is A4988 a good choice or not?
-Will there be any problem in controlling two stepper motors (at different speeds) using two motor drivers with Arduino Uno?
-Will be there any problem in using VEXTA PK243A1-SG18-C4 Motor with Arduino Uno?
All Regards,