One of the most important issues in wireless sensor networks is reliable communication. In this article, we present MAODV-SIM, a routing protocol that increases the reliability in a sensor network and which is based on AODV. Our protocol introduces multipath and signal intensity metric. We need to define what reliability is? How can we say that a protocol is more reliable than another? Which benchmark can be used? Multipath is needed to determine emergency routes that are required to find a new path to the destination if the first one fails. Then,to choose more reliable routes we use a different metric, the signal intensity metric which is based on 802.15.4 standard that defines two physical measurements : the link quality indication(LQI) and the energy detection (ED). Simulations show that MAODV-SIM increases reliability in sensor network.