Measuring the speed of a rotating object is a common requirement. Knowing the speed of table and ceiling fans, as well as ...

Abstract: This paper proposed a self-contained IoT sensor module which includes sensor for collecting various information, micro-computer and multiple solar panels for realizing dynamic cost reduction ...

Abstract: We developed a compact sensor module for hydroponics that measures the nutrient concentration and water level using simple oscillator circuits. Oscillation frequencies are measured and are ...

It's why DIY smart home projects suddenly got cheap (and actually doable) ...