Sensing and computing are essential elements that human makes an attempt to understand and perceive the analog world via digital gadgets. The analog-to-digital converters (ADCs) discretize the analog alerts whereas the information bus transmits digital knowledge between parts of a pc. With the rising of sensor nodes and the applying of deep neural networks, the power and time consumption limits 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 knowledge switch. Based on the mixing diploma, herein, we summarize 4 ranges of in-sensor computing within the discipline of synthetic olfactory. Within the first stage, we present totally different capabilities are carried out through the use of discrete parts. Subsequent, the information conversion and switch are exempted inside the in-memory computing structure with essential knowledge 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 additionally outlook the usage of steel nanoparticle gadgets to attain such in-sensor computing for bionic olfaction.