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

tothemoonn

Hi all,

I work in an addiction research lab where we give automatic infusions of cocaine to catheterized rats inside an operant chamber.  The trouble is that our syringe pumps cost around $700 a piece and they dont even come with variable speed capability (Yeah, $700 dollars for a motor that turns a screw that pushes in a syringe...at one speed).  As you would imagine however syringes come in all sorts of sizes, and drugs are mixed in all sorts of concentrations; so speed is a relevant variable.  I assume that I could fabricate something for FAR less.  I was wondering if anyone would have any suggestions as to where to start looking for suitable actuators and so on.  I know linear actuators are pretty expensive, but I assume there are myriad ways to achieve a similar motion.  All I need is to be able to adjust the rate the plunger on the syringe is pushed in, and have a button to stop and start it...simple right?  I would think even the arduino would be unnecessary, but I've been itching for a chance to get my hands dirty with one for a couple of years now.

Thanks very much!
Cameron

retrolefty

Well the simplest solution I can think of is to use a servo. Just convert the rotary action to a linear action through appropriate linkage/bell crank type thingee. Your software can control the depth of travel and the rate. Servos come in all sizes and torque ratings with optional quality metal gear trains etc. It should be a cheap project (relative to your $700 pump, no wonder why my health care costs are so high  ;) ) and a great excuse to have an arduino board work for a living.

Lefty

tothemoonn

Wow, that was fast.  God Arduino is a beautiful thing.

So my next question would be, where does the informed maker shop for these sorts of things?  Sparkfun and the Makershed seem pretty limited, but when I google things like actuator and servo I end up surfing through all these terrible industrial websites and catalogs with vague descriptions and bulk pricing.

CrossRoads

How about this - get a long screw with a flat sided nut on it that will sit inside a square column such that the screw is held in place and turning it back & forth causes the nut to move up & down the screw.
One wall has slot down its length, and eyelet attached to the nut (or sandwiched between 2 nuts) then moves up & down as screw is turned.
Attach a motor to the screwhead - or mount a cordless screw driver over the head of the screw and have the arduino control the screwdriver.
http://www.blackanddecker.com/power-tools/9074CTN%20A.aspx $15 if look around
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


How about this - get a long screw with a flat sided nut on it that will sit inside a square column such that the screw is held in place and turning it back & forth causes the nut to move up & down the screw.
One wall has slot down its length, and eyelet attached to the nut (or sandwiched between 2 nuts) then moves up & down as screw is turned.
Attach a motor to the screwhead - or mount a cordless screw driver over the head of the screw and have the arduino control the screwdriver.
http://www.blackanddecker.com/power-tools/9074CTN%20A.aspx $15 if look around


Another great suggestion.  Running with that idea it occurs to me that we have tons of extra pumps around, they run on a 120V wall outlet, but are triggered on and off by our computer hardware.  How hard might it be to modify the motor on those to get some sort of variable speed?

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