This work presents an optimized, low-cost interface to detect strain-induced martensite in austenitic steels using the four-point resistivity measurement model, employing the ATmega328P microcontroller and other carefully selected components. It was designed as a system with several subunits implemented as modules to greatly aid troubleshooting in case of system failure. It is suitable for testing low impedance metals, such as austenitic, ferritic, and martensitic steels. It ensures internet connectivity for better display and data processing, as well as current optimization, thus reducing overall power consumption, which makes the device ideal for use in off-grid environments. This meter injects currents from 0.1A to 1.5A. Its ability to accept analog input and display digital output gives it the advantage of minimizing system errors associated with data display and processing. The meter was tested through simulations performed in Proteus, Simulink, Matlab, Thingspeak, among others, according to the design characteristics, so the data generated were compared with the input values, which shows the good resolution and repeatability of the equipment.