Brain-inspired chips are helping electronic noses better mimic human sense of smell

After years of trying, the electronic nose is finally making major progress in sensing smells, almost as well as its human counterpart. That is the conclusion of a scientific review into the development of neuromorphic olfactory perception chips (NOPCs), published in the journal Nature Reviews Electrical Engineering.

The power of the human nose

Evolution has perfected the human nose over millions of years. This powerful sense organ, while not the best in the animal kingdom, can still detect around a trillion smells. The quest to develop electronic noses with human nose-like abilities for applications like security, robotics, and medical diagnostics has proved notoriously difficult. So scientists have increasingly been turning to neuromorphic computing, which involves designing software and hardware that mimics the structure and function of the human nose.

In this review, a team of scientists from China highlights some of the key advances in developing olfactory sensing chips. The paper focuses heavily on gas sensors because they are key components of the electronic nose system. They must physically detect odor molecules and convert them into electrical signals.

However, one of the major drawbacks of today’s systems is that they often can’t detect subtle smells. Also, there is an increasing demand for faster, more powerful electronic noses for monitoring air pollution, checking food safety in real time, and for non-invasive medical diagnostics (like ‘smelling diseases’).

Making chips more brain-like

The review emphasizes how scientists are overcoming these limitations with chips that mimic the brain’s efficiency. For example, they are designing chips that feature memristors and spiking neural networks (SNNs).

Memristors are electronic components that can store and process information simultaneously, like a brain synapse, while SNNs mimic how neurons send information via brief electrical impulses. By integrating these two bio-inspired elements, researchers are building autonomous, low-power electronic noses that can detect and distinguish smells that older systems can’t.

The most important advance has been making the chips work like tiny, efficient brains. Researchers achieved this by merging the sensors, memory and processing power all onto one chip. This solved the old problem of wasted power and allows electronic noses to use much less energy. Crucially, this bio-inspired design gives the system the ability to learn a new smell from just one sample and to distinguish complex odors (such as mixed gases) that confuse traditional electronic noses.

“By drawing inspiration from biological olfaction and integrating micro–nanoelectronics with AI technologies, these chips offer a promising solution to achieve real-time odor perception, learning and recognition, surpassing the limitations of traditional gas sensors, wrote the researchers,” said the researchers.

According to the review, key challenges remain in developing these chips into commercial products. These include overcoming sensor drift that causes accuracy to break down after weeks and months and ensuring that the neuromorphic hardware remains stable and reliable for years.

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