Seat Occupancy Detection Based on a Low-Power Microcontroller and a Single FSR

Gasulla

2020

Self Cite

This paper proposes, analyzes, and tests a wake-up circuit for a microcontroller (MCU) that uses a LED, operating as a photodetector, illuminated by a smartphone flashlight. The wake-up circuit consists of a high-pass filter and a voltage level translator that interfaces the LED, with a suitable resistor in parallel, to the MCU. When illuminated by a switching flashlight, the LED generates a square voltage that is conveniently converted in logic levels at the output of the wake-up circuit. A firmware embedded into the MCU additionally checks that a predetermined sequence of logic pulses at a given rate is accomplished to activate the MCU. The paper includes a theoretical analysis and experimental results that validate the proposed circuit.

Section: B Dynamic Responsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

LED-Based Wake-Up Circuit for Microcontrollers

Ripoll-Vercellone¹,

Gasulla

2020

Self Cite

“…Taking into account the benefits of using time instead of voltage as the medium to transmit information, time-based circuits have been extensively analyzed and developed in the last decade for sensor applications. For example, there are circuits that measure the charging or discharging time of an RC or RL network that includes a resistive [5]- [7], capacitive [8]- [10], or inductive [11]- [13] sensor. A similar approach has also been proposed to measure sensors that provide a voltagemodulated output [14], [15], but this is assumed of very low frequency or quasi static.…”

Section: Introductionmentioning

confidence: 99%

Demodulating AM Square Signals via a Digital Timer for Sensor Applications

Gasulla

2020

Self Cite

This paper evaluates theoretically and experimentally the performance of a timer-based demodulator applied to low-frequency amplitude-modulated (AM) square signals coming from sensor circuits. The demodulator extracts the amplitude of the AM square signal by measuring the period of a reference triangular signal that is altered by the AM signal itself, as already suggested in a previous paper but for AM sinusoidal signals. The demodulation and digitization are carried out simultaneously via a digital timer and without requiring a rectifier, a mixer, a low-pass filter, or an analog-to-digital converter, thus resulting in a simple and low-cost design solution. Unlike the sinusoidal case, this paper proposes to infer the amplitude of the AM square signal by measuring the bias of the period measurement with respect to the ideal (known) value. Experimental results show a non-linearity error lower than 0.03% full-scale span and a resolution of 13.3 bits.

“…Peripherals can be digital (e.g. a digital timer/counter [1], [2]), analog (e.g. an analog comparator [3]) or mixed (e.g.…”

Section: Introductionmentioning

confidence: 99%

Toward Non-CPU Activity in Low-Power MCU-Based Measurement Systems

2020

Self Cite

This paper evaluates the benefits of having peripheral-triggered peripherals in a microcontroller unit (MCU) intended for low-power sensor applications. In such an architecture, the functionality is moved from the central processing unit (CPU) to the peripherals so that a peripheral is able to trigger another peripheral with non-CPU intervention. For the sensor data logging application under study, both energy consumption and measuring time are reduced by a factor of two with respect to the case of applying an interrupt-based approach that requires the CPU intervention.