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Adding an Experimental Parameter

Customizability was a key design consideration when developing the eVOLVER. In Supplementary Note 3, we describe the utility and ease of writing software to program feedback between experimental parameters for designing novel experiments. In this note, we describe how one can customize the hardware to modify/add parameters of interest. Additionally, we present the components and systems used for the measurement and control of three core experimental parameters in each Smart Sleeve: stirring, temperature, and optical density.

Modifying, Adding, and Removing Experimental Parameters

A key feature of our hardware framework is that it enables adding, subtracting, and modifying components without changing the rest of the system (Supplementary Fig. 2). For example, if the user wants to add an LED to each culture vessel for dynamic light induction during continuous culture, traditionally this would require redesigning and rebuilding the entire system. In contrast, using the eVOLVER framework, the user can add experimental parameters with minimal modifications to the current system. For example, to add light induction as an experimental parameter, the user could follow these steps:
  1. 1.
    Modify the Smart Sleeve to incorporate the LED where desired on the device. This involves only redesign of the CMB, the 3D printed tube holder, and the aluminum sleeve. These components are simple to design and fabricate with minimal experience. Template designs are made available at
  2. 2.
    Plug in PCB to corresponding SA slot. The LED must be properly connected to the ribbon cable via the CMB, making an electrical connection to one of the 7 SA slots. To control an LED, a PWM board (same as above) can be used to control the intensity. Alternatively, if the user has additional specific requirements, one could engineer their own custom control PCB to plug into this slot to control the LEDs.
  3. 3.
    Program the Arduino micro-controller to customize how serial commands translate to LED brightness. First, set up a unique address of the Arduino micro-controller such that the serial commands matching this address will be interpreted by the correct Arduino. Second, custom routines can be programmed to permit rapid computation, sequential actions, or internal feedback. Template routines are made available at Specifics for implementing additional commonly desired parameters and functionalities in eVOLVER are found in Supplementary Note 7.