Small and inexpensive computing devices are becoming potential players in the Internet arena. Smart constrained devices are used for collecting or generating information which is later relayed to the designated servers. The information gathered must be adequately protected against all kinds of attacks during storage and transmission. However, most smart constrained devices have limited resources and unable to run most of the classical protocols that provide robust security. This article presents a lightweight mutual authentication protocol for resource constrained heterogeneous computing devices with high mobility. Our solution is novel as it facilitates two resource constrained devices to autonomously perform mutual authentication and establish a session key without sharing common parameters beforehand. Our proposed lightweight protocol is symmetric and uses simple primitives such as XoR, comparison and keyed-Hashed Message Authentication Code (HMAC) during mutual authentication. Moreover, our protocol requires minimum storage for storing few keys and parameters locally. The protocol is formally verified using AVISPA tool