The eVOLVER platform features tunable and independent stir rate control across culture vials. Stirring in eVOLVER is actuated by 12V brushless DC motors with attached neodymium magnets. The fastened magnets spin a stir bar (20 mm x 3 mm, PTFE coated) within an autoclaved glass vial (28 mm x 95 mm, borosilicate). The stirring module utilizes a single SA slot on the Motherboard; in the particular configuration described in this study, we utilized SA slot 1 (Supplementary Fig. 4). The two leads of the motor (12V & GND) are connected to a screw terminal on the component mount board, from which a ribbon cable connects the smart sleeve to the Motherboard. The PWM board (plugged into the SA slot) can control each motor independently to achieve different stir rates across eVOLVER vials. Briefly, the 16-channel PWM board amplifies a 3.3V signal from the Arduino microcontroller to a 12V signal to actuate Nature Biotechnology: doi:10.1038/nbt.4151 12 the motor. Arduino 1, which manages SA slot 1, was programmed to take in serial inputs from the Raspberry Pi and translate the serial values to different stir rates, determined by pulsing the motor ON and OFF at different ratios (Supplementary Fig. 4).

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