OpenDrop V4

OpenDrop V4

OpenDrop a modular, open source digital microfludics platform for research purposes. The device uses recent electro-wetting technology to control small droplets of liquids. Potential applications are lab on a chip devices for automating processes of digital biology.

Modular System

OpenDrop V4 Rendering

The OpenDrop V4 is modular electrowetting controller. The driver board is equipped with a connector that can host a circuit board cartridge with up to 128 electrodes. All electrodes can be separately activated with DC or AC voltage in the range of 160V – 300V. The connector also carries the virtual ground connection for a conductive top cover as well as a cartridge detection pin.

Between the cartridge and the driver board a space of 5.5 mm height allows for application specific components such as peltier elements for heating and cooling, electromagnets for magnetic beads or optical sensors for reaction measurements.

The driver board can be separated form the main board. This allows for easy replacement of the connector or drivers if damaged. And custom specific driver boards can be designed for extra functionality. Two extra signal lines P1 and P2 as well as GND and 3.3V power is available on the driver board.



OpenDrop V4 Top with Electrode Array
OpenDrop V4 Electronics
  • AC and DC voltage generated on the device form USB power. True AC voltage driving capability (up to 300VAC).
  • 32bit AVR SAMD21G18 microprocessor with plenty of memory and power
  • Electronic settings for voltage level, frequency and AC/DC selection
  • Electronic reading of actual voltage level
  • One connector for communication and powering (USB-C)
  • Optical isolation of the high-voltage electronics trough opto-couplers and PhotoMOS
  • New polyphonic audio amplifier and speaker (it’s a synth!)
  • Cartridge presence detection
  • Feedback amplifier
  • Super flat OLED Display
  • Nice joystick and 2 buttons, 3 LEDs
  • Reset button
  • All files open source on GitHub, designed on KiCAD
OpenDrop V4 Side View
OpenDrop V4 Schematics Main Board

Electrode Array

A printed circuit board holds the electrode array. The individual electrodes are connected to the backside of the circuit board through vertical interconnects (VIAs) and linked to the cartridge connector on the back.

  • Connector to connect electrode board with up to 128 channels
  • Gold coated 14×8 electrodes array, 2.75 mm x 2.75 mm in size
  • 4mil gaps between electrodes with an interlocking pattern
  • Reservoirs – the new electrode array features 4 CT-type reservoirs
  • Circuit board thickness: 1mm