Has anybody considered using syringe pumps for better control over dosing? DIY syringe pumps using 3D printing and other fabrication methods seem to be popular among people setting up low-budget biology labs.
Having watched the discussion here on the forum for most of the last year, it sounds like the peristaltic pumps in the BOM move fluid too quickly. People seem to be having trouble with achieving small, carefully controlled doses. I haven’t tried it myself. But, from what I see in people’s syringe pump videos, that route might be an easier way to get really good dosing control.
There are a couple syringe pump configurations you can use:
Manual refills: Use a regular syringe with a tube on it, and have a person fill it manually. Your machine just needs to squeeze the plunger at a controlled rate and detect when the syringe needs refilling. This looks good for moving small amounts of fluid slowly and gradually.
Continuous pumping: Instead of just a tube on your syringe, use the valve from a “Cornwall syringe”, or build the equivalent from a couple check valves and a tee joint. The Cornwall syringe configuration would draw liquid from one tube when your machine pulls the plunger and expel liquid through the other tube when your machine pushes the plunger.
Here are some of the good links I found by searching for “DIY syringe pump”, “syringe servo”, “3D printed syringe pump”, etc.:
- https://www.youtube.com/watch?v=-81ECglkDqA – “Syringe injector (10cc with 180deg servo)”
- https://www.youtube.com/watch?v=TH8st3B_bd8 – “Arduino controlled aquarium dosing pump”
- https://www.youtube.com/watch?v=LK7IJcSUMkM – “DIY Syringe pump” (this shows the valve from a Cornwall syringe)