A level sensing circuit board, comprising: a sensing capacitor having a positive plate (Cp) and a negative plate (Cn), the positive plate (Cp) corresponding to sensing plates (36a, 36b), the sensing capacitor configured to sense an electrical conductivity of a material causing a stimulus, the sensing plates being interconnected by an interconnection path, and the negative plate (Cn) corresponding to a ground plane of a printed circuit board, the ground plane being configured to surround the sensing plates (36a, 36b) laterally and from behind to act as a barrier that nullifies the response from the sensing plates (36a, 36b), and causing the sensing plates (36a, 36b) to detect only material placed in front of them; a variable frequency oscillator comprising a comparator with an input (-) coupled to the positive plate (Cp) of the sensing capacitor; and a signal processing module configured at least to: - respond to a received signal containing information about the electrical conductivity of the material causing the stimulus to the sensing plates (36a, 36b) that correspond to the positive plate (Cp) of the sensing capacitor directly connected to the input (-) of the comparator that forms part of the variable frequency oscillator, and - determine a proportional response containing information about the material causing the stimulus to the sensing plates (36a,36b), based at least partly on the received signal, and providing an output signal containing information about the proportional response. a sensing capacitor having a positive plate (Cp) and a negative plate (Cn), the positive plate (Cp) corresponding to sensing plates (36a, 36b), the sensing capacitor configured to sense an electrical conductivity of a material causing a stimulus, the sensing plates being interconnected by an interconnection path, and the negative plate (Cn) corresponding to a ground plane of a printed circuit board, the ground plane being configured to surround the sensing plates (36a, 36b) laterally and from behind to act as a barrier that nullifies the response from the sensing plates (36a, 36b), and causing the sensing plates (36a, 36b) to detect only material placed in front of them; a variable frequency oscillator comprising a comparator with an input (-) coupled to the positive plate (Cp) of the sensing capacitor; and a signal processing module configured at least to: - respond to a received signal containing information about the electrical conductivity of the material causing the stimulus to the sensing plates (36a, 36b) that correspond to the positive plate (Cp) of the sensing capacitor directly connected to the input (-) of the comparator that forms part of the variable frequency oscillator, and - determine a proportional response containing information about the material causing the stimulus to the sensing plates (36a,36b), based at least partly on the received signal, and providing an output signal containing information about the proportional response. - respond to a received signal containing information about the electrical conductivity of the material causing the stimulus to the sensing plates (36a, 36b) that correspond to the positive plate (Cp) of the sensing capacitor directly connected to the input (-) of the comparator that forms part of the variable frequency oscillator, and - determine a proportional response containing information about the material causing the stimulus to the sensing plates (36a,36b), based at least partly on the received signal, and providing an output signal containing information about the proportional response.