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Topic: New to Arduino, guidance on a simple syringe pump for my lab. HELP! FOR SCIENCE! (Read 4971 times) previous topic - next topic

zoomkat

You could use the below modified servo to turn a threaded shaft, and connect the now external pot to the moving plunger via linkage to have plunger position control.

http://www.lynxmotion.com/images/html/smodh2.htm
Google forum search: Use Google Advanced Search and use Http://forum.arduino.cc/index in the "site or domain:" box.

westfw

Quote
"(There was a recent study done of "software quality...."
  I just happen to think this one is in my league.

Oh sure; I didn't mean to imply that it wasn't, or even that the lab software that "doesn't meet modern coding standards" didn't work or wasn't suitable for that environment.  You can improve software reliability quite a lot if you have intelligent users that follow instructions, and a lot of "modern practices" are aimed at preventing bad behavior in the face of intentional abuse...  And the truth is that there are a lot of useful things one can do with software that don't require much in the way of "computer science" (or "computer engineering")  to create.  (otherwise, Arduino wouldn't work...)

tothemoonn

Thats what I'm hoping.  I also hope that last comment didn't sound retaliatory. I'm just very green when it comes to programming, electricity... all of this stuff (heck I'm a behaviorist haha). I just meant it as a sort of disclaimer that I'm aware of my extreme lack of knowledge and that I dont expect easy answers(though I might hope for them), but I'm committed to the dig and doing it right :)

I really appreciate your input, I actually scavenged an old cd rom today to start tinkering with over the next few weeks.  Im hoping to learn, first of all, how to find the operating voltage and all that on them...and then to start learning about how to implement pwm (though ill likely play with that on an LED first).

mweisz481

Came across the post a bit late, so maybe you have found a solution.  Here's an example of one I built to dispense fluids from a syringe very accurately at a wide range of speeds.

A non-captive linear actuator (a stepper motor where the shaft is threaded and moves up and down) works quite well in this application.  You can get a driver card for $20 from sparkfun.com http://www.sparkfun.com/products/10267 for bi-polar steppers which will save you trouble if you're unfamiliar with the hardware.  All you'd need is an arduino, the motor, and the driver.  You just have to wire the step and direction pins to the Arduino and write a bit of code to move the stepper up and down.  If you get a stepper with 20 threads per inch and with 200 steps per revolution you can move the syringe in .00025" increments for fine dispensing.

Sample code with a button for up and down:

Code: [Select]
#define stepPin 3
#define dirPin 4
#define up 5
#define down 6

void setup() {
 pinMode(stepPin, OUTPUT);
 pinMode(dirPin, OUTPUT);
 pinMode(up, INPUT);
 pinMode(down, INPUT);
}

void loop() {
 if(digitalRead(up) == HIGH)
   {
     digitalWrite(dirPin, HIGH);
     while(digitalRead(up) == HIGH)
       {
         digitalWrite(stepPin,LOW);
         delayMicroseconds(2);
         digitalWrite(stepPin,HIGH);
         delayMicroseconds(800);  //adjust this value for dispense speed
       }
   }
 if(digitalRead(down) == HIGH)
   {
     digitalWrite(dirPin,LOW);
     while(digitalRead(down) == HIGH)
       {
         digitalWrite(stepPin,LOW);
         delayMicroseconds(2);
         digitalWrite(stepPin,HIGH);
         delayMicroseconds(800);  //adjust this value for dispense speed
       }
   }
}


You'd most likely want to flesh out the code to keep track of the steps moved, and hence how much is dispensed.  You can add in an LCD screen for about $20 for a nice interface to select dispense speeds, etc. if you want a more robust system.

wb8nbs

This might help

http://www.mpja.com/prodinfo.asp?number=17265+MD

smaller one

http://www.mpja.com/prodinfo.asp?number=17284+MS

He who dies with the most software wins.

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