An electronic sensing system for detecting a target gas, the electronic sensing system comprising: a target gas sensor configured to detect a resistance of the target gas sensor; a reference sensor configured to detect a resistance of the reference sensor; a resistance comparator including a potentiometer, the resistance comparator being electrically connected to the target gas sensor and the reference sensor, wherein the potentiometer is configured to be adjusted to determine a first resistance in response to the resistance of the target gas sensor and a second resistance in response to the resistance of the reference sensor; a system on a chip in electronic communication with the resistance comparator, the system on a chip being configured to determine a target gas concentration in response to the first resistance and the second resistance; a multiplexer electrically connecting the resistance comparator to the target gas sensor and the reference sensor, wherein the multiplexer comprises: a first port electrically connected to the target gas sensor, a second port electrically connected to the reference sensor, and an output port electrically connected to the resistance comparator; and an energy source, characterized in that the electronic sensing system further comprises: a printed circuit board having a first side and a second side opposite the first side; and in that the potentiometer is a digital potentiometer; and a majority of components of the electronic sensing system are located on the first side of the printed circuit board and the energy source is located on the second side, the energy source being electrically connected to components on the first side of the printed circuit board and being configured to provide electrical energy to at least one of the components on the first side of the printed circuit board. a target gas sensor configured to detect a resistance of the target gas sensor; a reference sensor configured to detect a resistance of the reference sensor; a resistance comparator including a potentiometer, the resistance comparator being electrically connected to the target gas sensor and the reference sensor, wherein the potentiometer is configured to be adjusted to determine a first resistance in response to the resistance of the target gas sensor and a second resistance in response to the resistance of the reference sensor; a system on a chip in electronic communication with the resistance comparator, the system on a chip being configured to determine a target gas concentration in response to the first resistance and the second resistance; a multiplexer electrically connecting the resistance comparator to the target gas sensor and the reference sensor, wherein the multiplexer comprises: a first port electrically connected to the target gas sensor, a second port electrically connected to the reference sensor, and an output port electrically connected to the resistance comparator; and an energy source, characterized in that the electronic sensing system further comprises: a printed circuit board having a first side and a second side opposite the first side; and in that the potentiometer is a digital potentiometer; and a majority of components of the electronic sensing system are located on the first side of the printed circuit board and the energy source is located on the second side, the energy source being electrically connected to components on the first side of the printed circuit board and being configured to provide electrical energy to at least one of the components on the first side of the printed circuit board. a printed circuit board having a first side and a second side opposite the first side; and in that the potentiometer is a digital potentiometer; and a majority of components of the electronic sensing system are located on the first side of the printed circuit board and the energy source is located on the second side, the energy source being electrically connected to components on the first side of the printed circuit board and being configured to provide electrical energy to at least one of the components on the first side of the printed circuit board.