Badge Documentation

Useful Links

Badge Components

  • Badge
  • Lanyard
  • Acrylic Base
  • Acrylic Frame
  • Paper Box Wall
  • 4 Screws
  • 4 Nuts
  • Parafilm
  • Q-tips
  • Pipette
  • Ground Wire

You will also need

  • Computer
  • USB C cable (the new one)
  • Silicon Oil < 6cSt


This system uses high voltage! Make sure that the High Voltage switch is in the OFF position!
This system needs to be clean clean clean. Any dirt or hair or dust or other stuff will make it not work.
Microfluidics is HARD! Do not be surprised if your first attempt is a failure

  1. Fold the paper box wall at the laser cut corners and insert the paper tabs into the base slots.
  2. The paper box wall has two cutouts. One for the USB connector, and one for the reset switch.
  3. Make sure you fold the paper in the right direction!
  4. Connect one end of the ground wire to the GND pad on the badge. Wrapping in on or soldering is OK.
  5. Place the badge on top of the acrylic and paper box, and insert the screws from the bottom.
  6. Don’t put the nuts on yet, We will do that later.
  7. Clean the electrode surface with alcohol and a clean cloth. The surface must be super duper clean!
  8. Create the Hydrophobic Surface:
    • Needs:
      • Parafilm
      • Silicon Oil ( < 6cSt) Must be pure, not suspended in anything else like H2O or alcohol, etc.
  9. Cut a piece of parafilm. Two squares should be enough. Stretch the parafilm so that it is super thin. It should be ~12nm thick, which is about half a mil. Make sure there are no tears or wrinkles in the film. It helps to tape one edge to a table and the other to a ruler or other straight edge. While you have the film stretched out nice and thin, wrap it around the edges of the acrylic frame.
  10. Use a q-tip to spread a thin film of silicon oil on the entire electrode surface.
  11. Place the frame with the stretched parafilm onto the board and secure with screws/nuts.
  12. The parafilm should be in contact with the oiled electrodes and not have any bubbles.
  13. Use a q-tip to spread a thin film of silicon oil on the top surface of the parafilm. Make sure not to tear the film!
  14. Applying a droplet
    • Use the pipette to place a droplet. When you do so, make sure that the drop is not bigger than the electrode.
    • Touch the droplet with the free end of the ground wire to remove any static charge in the droplet.
    • Make sure that you don’t poke a hole in the parafilm with the ground wire!

    • The code that runs on the OpenDrop is on the OpenDrop GitHub. There are three files.

    OpenDropV31_Joy_Resevoir Arduino Sketch

    This is the code that is already on the badge. When you turn in on, you are prompted to press SW2 (Switch 2 is the switch on the bottom right). When you press SW2, the OpenDrop attempts to move a droplet from the lower right resevoir. You can then use the joystick on the bottom idle of the board to move the droplet around. Pressing SW1 (button on the bottom left) will allow you to change modes. You can change from DC to AC voltage, Change the target voltage to between 160V and 300V, And adjust the frequency.

    OpenDropV31_Com Arduino Sketch

    This sketch looks like it interfaces with a serial port. When the OpenDrop receives the correct command, it will move a droplet.

    OpenDropApp Arduino + Processing

    This Arduino and Processing code allows you to control the position of the droplets with the computer. You can program droplet movement and move multiple drops at the same time! Super cool!


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