V. EXPERIMENTAL RESULTS
To simulate blood circulation in the veins and arteries, a
pump (Harvard Apparatus, Pump 11 Pico Plus Elite) is used to
inject the liquids through the channel at a predetermined flow
rate. In our tests, we used a flow rate of 80 μl/s. The complete
experimental set-up for testing the prototype is shown in Fig.
4, which shows the micro-tube between several LEDs and
photodetectors mounted on two separate printed circuit boards
(PCB) and enclosed inside a plastic housing. An additional
PCB that includes the analog front-end, the LED driver, and
the low dropout regulator is used. The collected output
voltages are digitized by the internal 12-bit analog-to-digital
converter are sent to a host PC through a serial port.