Our Sense-U Baby Monitor detects the baby's abdominal breathing very sensitively and accurately. Any tiny fluctuations can be detected by our sensor unless it is absolutely static. So, if the device is on a table/pillow/mattress or other unstable surfaces, it will detect fluctuations. Please make sure you put the device on a smooth and still table and wait several minutes till it is static. And the Sense-U Baby is not suitable for co-sleeping or bed-sharing.