Stirring
This has worked well for chemostat work at UW Sauro Lab. Air is injected through a long needle going to the bottom of the tube. However air bubbles might interfere with turbidity measurement.
Klavins lab turbidostat uses magnetic stirrer.
Initial configuration of hivebio stir drive:
Magnets shown are anchored in wooden rotor with hot melt glue. 1.5-volt AA cell runs it a little bit fast. Motor shown is 0.780" dia x 0.588" across flats x 1.138 long body (not including front shaft extension 0.300", rear shaft extension 0.035").
Stepper vs brush: issue #1
| item | mfr P/N | ||
|---|---|---|---|
| stir bar, Oval, Length 15 mm, Diameter 6 mm, PTFE | SBM-1506-OVL | stirbars.com | $3.80ea @10pcs |
| 1/4"x 1/8" Disc - Neodymium Rare Earth Magnet N48 | M14x18DI | apex magnets | $0.45ea @ 20pcs |
| DC motor "130" size | Adafruit 711 | Adafruit | $1.95 ea |
(Some of these from Klavins lab bill of materials)
| item | mfr P/N | ||
|---|---|---|---|
| stir bar 9.5 x 19 mm (3/8 x 3/4") | VWR 58949-006 | VWR | $11.22ea |
| disc magnet 1/4" dia x 1/8" thk | ND012-N50 | magnet4less |