Background

Syringe pumps are excessively expensive. The expansion of the hobbyist 3D printing market has lowered the cost and increased the availability of 3D printer components due to demand for DIY kits and replacement parts. By leveraging these low cost readily available components, along with micro-manufacturing services (OSH Park, Ponoko, Shapeways etc.), there is no reason that the functionality of a expensive commercial pump can’t be replicated at 1/10th the cost. Therefore, my goal was to make an easy to assemble, open-source syringe pump that is an order of magnitude less expensive without sacrificing reliability and resolution.

I am not the first to build an DIY syringe pump. Here are some similar projects:


Design

The major difference between my take on the DIY syringe pump, and the ones above, is my abstaining from using 3D printed components. I chose to use lasercut parts because they are more accurate, more precise, stiffer, and more condusive to rapid iteration and/or making large quantities (minutes to lasercut instead of hours to 3D print).

Features

Volume dispense resolution

Using a 60 mL syringe, the theoretical volume dispense resolution can be calculated as 2.65 μL. The code below demonstrates the calculation. You can modify and run the code here.

from math import pi
#Syringe
innerDiameter = 26.7 #mm
syringeArea = pi * (innerDiameter / 10.0)**2 / 4.0 #cm^2

#Lead screw
pitch = 2 #mm
numStarts = 4
lead = numStarts * pitch / 10.0 #cm

#Stepper Driver
microSteps = 16

#Motor
numSteps = 200 #steps/revolution

#Result
linearResolution = lead / (numSteps * microSteps) #cm
volumeResolution = linearResolution * syringeArea #cm^3 or mL
print(u"{:0.1f} \u03bcm linear resolution".format(linearResolution * 1e4))
print(u"{:0.4f} \u03bcL volumetric resolution".format(volumeResolution * 1e3))

Electrical Design

More to come…

Mechanical Design

Old Versions

Version 1

Latest

2 pumps mounted to behavior rig

Demo Videos

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