A device, system and method for in-vivo sensing (e.g., pH sensing, pressure sensing, or other sensing) may include more than one sensor receiving in-vivo data. The sensed data may be analyzed to, for example, determine a gradient or fluid flow. A device including multiple sensors may be held or immobilized...http://www.google.ca/patents/US20040193029?utm_source=gb-gplus-sharePatent US20040193029 - Measuring a gradient in-vivo
