The use of the Atomic Force Microscope (AFM) as a teaching tool in hands-on laboratory activities for electronics engineering curricula is proposed. In addition to providing nanometric resolution in topographic imaging, profilometry and metrology of micro-and nano-fabricated devices, pivotal in modern electronics, the AFM represents an excellent instrument to: (i) experiment with the negative feedback control of a sophisticated opto-electro-mechanical system, (ii) perform nanoscale current (DC) and impedance (AC) measurements and maps by means of conductive tips. Examples and results with both discrete and integrated low-noise current amplifiers are here reported.

We present a portable electronic sensor system for real-time monitoring of dust deposition in avionics and space applications, where particle contamination can alter the operation of instruments and scientific payloads. To measure and verify the deposition events on space hardware during fabrication, assembly and in the launch phase, a compact system based on an integrated electronic CMOS chip has been designed. The chip tracks the capacitance variation between two interdigitated electrodes, affected by the arrival of dust, ensuring single event monitoring and detection of particles with a diameter down to 1 µm. The system is completed by a low-power microcontroller for setting the chip operation, an analog-to-digital converter for the acquisition of the particle deposition events, a Bluetooth transmitter for data read-out and all the other hardware and software functionalities that ensure completely autonomous operations.

A multichannel portable instrument for on-chip optical absorption spectroscopy is presented. The system can house photonic chips having up to 6 sensing sites operating in parallel, allowing real-time simultaneous detection of multiple chemicals. A 6-channel CMOS lock-in front-end performs the amplification and demodulation of the signals from the integrated light detectors, while an FPGA is chosen for signal acquisition and analysis. A digital real-time ratiometric processing cancels out the effect of laser power fluctuations to achieve high sensitivity in monitoring the presence of the analytes, as demonstrated with the detection of an acetone sample. Compact size for portability, real-time parallel detection and flexible FPGA processing make this system suitable for environmental investigations on many different pollutants, both in the near- and mid-infrared wavelength range.

A novel impedance micro-sensor measuring with 0.5 μm resolution the thickness of undesired chemical or bacterial films fouling the surfaces of in-line probes, monitoring water ducts, is presented. The circuit for lock-in impedance detection (operating at 5 MHz, 10-bit resolution) is illustrated. It is embedded in a multi-sensor IoT water quality monitoring node, enabling self-diagnostics and on-demand maintenance. The credit-card-sized board features pH, temperature, 4 conductivity probes and the film monitor, along with anti-bubble actuation and wireless GSM transmission. The additional power consumption added by the sludge sensor is only 5% of the total.

A mixed-signal electronic system allowing closed-loop control of 16 independent integrated photonic devices equipped with CLIPP transparent optical probes (-35 dBm sensitivity, 50 kHz speed) is presented. It features a 32-channel CMOS lock-in front-end (203 nV /√Hz noise, 100 dB dynamic range), interfaced via conditioning chains to multiple ADCs and DACs driven by a Xilinx Spartan-6 FPGA for real-time processing, including the generation and demodulation of multiple pilot tones for channel labeling and dithering-based feedback. The results of the platform characterization are reported, along with the first application of automatic control applied to a novel all-optical unscrambler for mode-division multiplexing.