Devices and methods for programmable microscale manipulation of fluids

A method for determining a polar position and a radial position of a pickup in a reference frame of a rotating device comprising:

• means for detecting a first marker on the device;
• means for detecting a second marker on the device, wherein an angular distance from said first marker to said second marker is a non-constant function of a radial position of the pickup;
• means for determining the time elapsed between detection of the first marker and the second marker;
• determining a radial position of said pickup from said elapsed time and a rotation period of said rotating device;
• and
• determining a polar position of the pickup a first time using the difference between the first time and a second time corresponding to the detection of a marker and the rotation period of the rotating device.

A method for determining a polar position and a radial position of a pickup in a reference frame of a rotating device comprising:

• recording a first time at which a pickup detects a first marker on a rotating device;
• recording a second time at which the pickup detects a second marker on the device, wherein an angular distance from the first marker to the second marker is a non-constant function of a radial position of the pickup;
• determining the radial position of the pickup from the difference in time between the second time and the first time and a rotation period of the rotating device;
• and
• determining a polar position of the pickup at a third time using the difference between the third time and a fourth time corresponding to the detection of a marker and the rotation period.