Compact, battery and USB powered, magnetic stirrer

This is a portable magnetic stirrer I designed for field titrations. It's perfect for field titrations, or for operating in environments without 240V power, such as fridges or glove boxes. This stirrer uses a pair of AA rechargables*, or can run from any USB power source. A draining drawer stores the stirring bars, and can be also used as a sieve/washing tray (25mm stirring bar included).

It should be printed in white so that colour change of chemical reactions can be easily observed. The stirrer can stir volumes from tiny vials up to 1000ml..

Compact dimensions and light weight make it easy to pack the stirrer in with other field gear. This stirrer is ideally suited to work at remote sites, where equipment has to be carried in. It’s small size also means that it could be easily bundled as part of a titration kit.

The lack of protruding knobs keeps the controls protected and, as an added benefit, allows for easy stacking of stirrers for storage.

Both USB and battery power sources mean that this stirrer is capable of being deployed in the field or permanently in a lab. In addition, it can be used for very long timeframes in unpowered environments through the use of commonplace USB power packs.

If you'd like to buy one, contact me. If you prefer to make your own. Enjoy. :D

It needs:
1.8V DC PWM controller - common on ebay. See pic.
AA battery terminals with tabs - I used keystone 52XX series.
A low voltage multiplexer - eg: FP1320 (or diodes if you prefer)
DC motor - eg: Multicomp MM18
10x3mm magnets.
A USB cable.
A bunch a 15mm M3 screws and nuts.
6 screws for feet/cable clamp.

This is a challenging series of prints, many of which need very effective and carefully considered support. If your printer isn't dialled in, then I'd recommend you find an easier print.

Lid prints upside down.
Doors on their sides.
Drawer right side up.
Baseplate right side up.
Feet. right side up.

Build instructions:
Print parts
Magnets are a push fit into the magnet bar
Magnet bar is a push fit onto the motor (Should need a lot of force - eg a vise)
Wiring should be pretty self explanatory. DC from batteries and USB to the multiplexer. Then DC to the PWM controller.

Note: I am not going to help you with print settings, wiring, or with finding suitable components. There's a bit of variability, especially in terms of PWM controllers and motors. It's up to you to ensure that the parts you've selected are suitable and that you have the printing experience required to print challenging parts. Also. These files are tested in Cura and Slic3r PE. If they don't work in your slicing software, let me know, but don't expect an update. It's not likely to be a high priority for me.