DIY Brushless Magnetic Turbo Stirrer

This is a DIY magnetic stirrer I designed to upgrade my old "pc-fan-approach"

Things needed:

1x 300mm GT2-belt

2x 608zz or 608rs bearings

1x M8x40mm or M8x50mm bolt

1x M8 Locknut

1x 2212 Brushless motor (I used an A2212/13T with 1000KV) with 4xM3x5mm Screws

1x ESC for brushless motor

1x (recommended) Propeller mount (used to mount the pulley on the motor)

1x (alternative to above) M3 Screw/Grubscrew + M3 Nut (about 6mm long)

1x (recommended) 40mm 12V fan with 2xM3 screws (length depends on your fan)

8x (recommended) 8x3mm disk magnets

1x 12V source that can drive your motor + fan

1x (optional) A metal plate 100x100x1mm (ideally a non magnetic metal like copper or aluminium)

Printed Parts:

Note: The Pulleys used in this design are based on the "Parametric Pulley for toothed belts in OpenSCAD" by "0scar" ( https://www.thingiverse.com/thing:2758711 )

You need the "MainPulleyV2", the "BaseSkeleton_Lite" and either the "motorPulley" or the "motorPulley_screwMount" the latter is untested.

For mounting the magnets I included "MiniMagnetInsert8mm" whih I use with 4 mini 8mm disk magnets each.

The MainPulley contains 8 holes where you can place the inserts according to your "stir fish" (is it called that?).

You can print two "SidePart" and a "BackPart" to hold the metall plate above the stirring mechanism. It is pretty solid, I tested it with up to 500g load and there were no issues but it may depend on the material used.

Assembly:

1. Free the holes in the printed parts (the small layer should help with bridging). There are 5 holes where the motor should be placed (4 for the screws and 1 from above for the motor axis) and 1 hole for the M8 bolt.
2. Mount the Motor with the leads out to the side on the BaseSkeleton with 4xM3x5 Screws (mine came with the motor)
3. Mount the motorPulley to the axis of the motor
4. Put the bolt through the MainPulley, then a 608 bearing, then the BaseSkeleton and another 608 bearing.
5. Secure the assembly from step 4 with the M8 locknut. (Not too tight, it needs to be able to spin freely)
6. Put the GT2x300 belt on
7. Insert your magnets into the inserts and place the inserts in the desired position on the MainPulley
8. (optional) Screw the fan into the two holes behind the motor, so that the motor is cooled by the fan
9. (optional) With a sharp knive carefully remove the supportlines in the top slots of the "SideParts"
10. (optional) Slot the two "SideParts" into the slots on the bottom of the BaseSkeleton
11. (optional) You can now insert the 100x100mm plate into the side pieces
12. (optional) Gently push the "BackPart" into the slots of the sides

Software

For the moment I use a very basic Arduino snippet to control the speed with the serial terminal.

You could basically use anything you want, like an RC-Remote or anything that can tell the ESC to spin the motor.

Just for completion I added my Arduino code. I take no responsibility in it destroying something because it is slow.

You can send it a value from 0 to 180 (no CR or LF, 9600 baud) and after a read-timeout it will start accelerating or decelerating to the target speed (0 is instant).

Connect the ESC-signal to Arduino-pin9 and ESC-GND to Arduino-GND.

Notes

The software will change hopefully.

If you want to use other magnets I included an OpenSCAD template for the Inserts that you can use as a starting point.