Steerable medical instruments are used to reach difficult locations in the body during minimally invasive surgery (MIS). Researching these instruments helps to further improve their performance and reduce their size making them even less invasive. However, developing new technology can be expensive and often complete custom test rigs are build for these instruments. This thesis presents the design, manufacturing and validation of an affordable, open-source prototype test setup for multi-segmented tendon-driven manipulators aimed at stimulating academic innovation of these manipulators. The prototype allows manipulators to be changed swiftly for other or iterated designs. Computer aided design (CAD) was used to create the design and a novel low-cost 3D printed force sensor comprising a permanent magnet and Hall effect sensor was proposed costing only €2.11. The prototype uses readily available off-the-shelf components and custom 3D printed parts that can be manufactured using hobby grade fused deposition modeling (FDM) printers. Despite the prototype working as intended, there are some tolerance issues in the actuation mechanism and viscoelastic behaviour in the printed force sensor that requires more research. However, the prototype setup already has the potential to be used for preliminary testing of tendon-actuated manipulators. Future work should focus on improving the 3D printed force sensor for enhanced performance and reliability. This work contributes to the progression in testing and validating tendon-driven manipulators.