Fecobionics

The basic design of Fecobionics has been described^22,23 (Fig. 2). Fecobionics was 12-mm-OD, 10-cm-long and made of Silicone rubber (PS6600, Yipin Mould Material Ltd, China). It contained pressure sensors and electronic circuit boards. Miniature pressure sensors (MS5837-30BA, TE connectivity, USA) were embedded in the silicone rubber core at the front, inside the bag, and at the rear of the core. The front and rear sensors pointed in the direction of the defecatory trajectory.

Schematic of the system with the wired Fecobionics device and the data collection device including monitor. The soft resin core of Fecobionics contains the central processing unit and three pressure sensors placed at the front, rear and inside the bag. Furthermore, it contains two Motion Processor Units for determination of bending (not used in this study). Wires and a filling tube is attached at the front. P = pressure sensor.

A 30 μm-thick and 8 cm-long polyester-urethane bag spanned most of the core length. The spherically shaped bag contained up to 80 mL without being stretched and had a maximum diameter of 6 cm. The bag was connected through a thin tube extending from the front of Fecobionics to a syringe containing saline.

With the architecture, silicone hardness shore (A5) and the bag, Fecobionics obtained shape and consistency that corresponds approximately to type 4 (range 3–4) on the Bristol stool form scale²⁹. The range from types 3–4 is found in + 60% of NS²⁹. Wires were threaded inside a thin tube extending from the front to a PCs USB port for power supply and real-time data transmission and display of data. Further processing was done in Matlab.