Fig. 3: Electronics design and in-vitro demonstration of the UBVM device.
From: An integrated and flexible ultrasonic device for continuous bladder volume monitoring
a Photograph of the UBVM device. b Functional block diagram of signal transmission lines of the UBVM device electronics. c Timing diagram of the UBVM electronics. A transducer channel is selected by the MCU and the MUX. Two sets of unipolar pulses with 180° phase difference allow the pulser to generate bipolar high voltage pulses. Received echoes are passed to the receiver circuitry via the internal switch of the pulser. Echoes are amplified, passed through the comparator for echo timestamp detection, and transferred to the mobile phone for processing and visualization. d Schematic drawing of the pulse-echo setup to demonstrate the wireless pulse-echo capability at various frequencies. Echo timestamps displayed on the mobile phone exactly correspond to the raw echo signals on the oscilloscope. e Schematic drawing of the in-vitro setup of the whole system. The test set-up mimics the bladder with flasks in deionized water, where the transducers were connected to the electronics with a 1-m-long flex cable. f Comparison of the actual volume and the measured volume of flasks with various volumes and shapes (n = 10), with a mean relative error of 14.85%.
