Go Down

Topic: New to Arduino, guidance on a simple syringe pump for my lab. HELP! FOR SCIENCE! (Read 4 times) previous topic - next topic

CrossRoads

Yeah, that looks like a Much improved version of what I was describing :) :)
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

tothemoonn


Syringe pumps deliver their contents VERY slowly (in the range 10ml per hour; probably less for rats?) and hopefully very regularly.  Picture one of those 4 RPM timing motors driving a precision ball screw, pushing the plunger.  Just the thing for keeping your wife painless during baby delivery :-)  Servos don't have enough resolution.

A geared stepper motor driving some sort of screw arrangement is probably a good start.  In fact, you might start with a computer's CD drive; they usually have a stepper driving a ball screw to move the heads (over 30mm or so of travel distance.)  Insert a bunch of gearing in between the stepper and the screw, afix some sort of lever to the head to push the plunger, and you'd be pretty close.  You'd even have a sturdy platform to mount things on.

Hmm.  They seem to also get used in rep-rap like machines (extruding polymers for 3d-printing.)  And they show up on eBay quite a lot.  (Some broken.  Although adding arduino-based electronics to existing mechanics might be a viable strategy.)

http://blog.reprap.org/2005_03_01_archive.html
http://www.youtube.com/watch?v=Gq4RQHLfJA4

I don't know how publishable research is when it's made using "questionable" equipment.  It may divide into two catagories: "Your homemade XXX is very clever!" and "Your use of homemade YYY completely invalidates everything you've done!"  (There was a recent study done of "software quality" in lab equipment of the sort made by people who studied, you know, biology or chemistry or one of those other real sciences rather than spending a decade or so in the software industry figuring out the many reasons that SW breaks all the time.  It wasn't flattering...  (sorta like: "people who studied computers and spent their careers writing SW still produce crap.  What did you expect from people who took two CS classes in college and went into lab research?"  Ouch.)



Thanks for the thorough reply, I'll look into that cd drive idea.  I think I may have mislead you with regard to the resolution I would need.  I need to move the plunger a distance of about 3 inches over a period of roughly 20 seconds, one time at the start of a session.  Normally we infuse by hand counting the seconds off as best we can (which has been accepted on our past publications).  For this experiment though we're interested in seeing a behavioral effect that should onset around 30 seconds after infusion, so it would be nice to be fully infused within +-2 seconds of our target.  (The pumps we own already are for experiments where the rats self administer with a lever)

tothemoonn

"(There was a recent study done of "software quality...."

P.S. - I'm no stranger to that sort of thing, believe me haha.  No lie, I have seen PhDs cover screws in modeling clay to try to keep them from backing out....Thankfully I come from a long line of carpenters and machinists, and though I didn't follow in the footsteps, I did learn that nothing is worth building if its not done absolutely right.  I just happen to think this one is in my league.

retrolefty

I've seen a TV documentary where the rats are given a choice of food or cocaine and end up dead of malnutrition. Amazing thing addition.

Lefty

tothemoonn


I've seen a TV documentary where the rats are given a choice of food or cocaine and end up dead of malnutrition. Amazing thing addition.

Lefty


Ohh yeah, we study it with cocaine, amphetamine, MDMA, alcohol, food...sex, all that good stuff.  Its amazing how many people still think it's a simple matter of willpower.

Go Up