A low-cost modular PCB assembly for functional and in-circuit testing.

This paper presents the design and implementation of a modular, low-cost printed circuit board (PCB) assembly to perform in-circuit testing (ICT) and functional testing (FCT) of electronic assemblies during prototyping and small-scale production. The hardware integrates multi-parameter measurement capabilities-including multiple testing functions, programmable voltage stimuli, relay-based switching matrices, voltage/current/resistance/capacitance measurements, and functional signal testing, all coordinated by an embedded MCU on a modular PCB assembly. Unlike conventional modular ICT/FCT platforms, the system emphasizes architectural integration, reduced structural complexity, and ease of deployment in resource-constrained environments, including small- and medium-sized enterprises (SMEs) and in-house prototyping laboratories. The design rationale, hardware architecture, and implementation are described in detail, along with representative experimental validations that demonstrate functional and practical measurement ranges. All design files, including schematics, PCB layouts, firmware, and a bill of materials, are openly available to support reproducibility and reuse. Prototypes were built and tested in automated functional test setups to verify their performance and proper operation. The results show that a modular, low-cost PCB assembly can effectively carry out testing tasks typically handled by expensive commercial systems, providing a versatile and low-overhead alternative to end-of-line test equipment.