Sensing and computing are two necessary methods by which people try and understand and perceive the analog world via digital gadgets. Analog-to-digital converters (ADCs) discretize analog alerts whereas the info bus transmits digital information between the elements of a pc. With the rise in sensor nodes and the appliance of deep neural networks, the power and time consumption restrict the increment of knowledge throughput. In-sensor computing is a computing paradigm that integrates sensing, storage, and processing in a single machine with out ADCs and information switch. In accordance with the mixing diploma, herein, we summarize 4 ranges of in-sensor computing within the subject of synthetic olfactory. Within the first degree, we present that totally different capabilities are performed by utilizing discrete elements. Subsequent, the info conversion and switch are exempt inside the in-memory computing structure with needed information encoding. Subsequently, in-sensor computing is built-in right into a single machine. Lastly, multi-modal in-sensor computing is proposed to enhance the standard and reliability of the classification outcomes. On the finish of this minireview, we offer an outlook on using metallic nanoparticle gadgets to attain such in-sensor computing for bionic olfaction.