The rising need for elderly care, child care, and intrusion detection challenges the sustainability of traditional systems that depend on in-person monitoring and surveillance. The current state-of-the-art technology heavily relies on Infra-Red (IR) and camera-based systems, which often require cloud computing. It leads to higher latency, data theft, and privacy issues of being continuously monitored. This paper proposes a novel tinyML-based single-chip radar solution for on-edge sensing and detection of human activity. Edge computing within a small form factor solves the issue of data theft and privacy concerns as radar provides point cloud information. Also, it can operate in all environmental conditions like fog, dust, and low light. This work used the Texas Instruments IWR6843 millimeter wave (mmWave) radar board to implement signal processing and Convolutional Neural Network (CNN) for human activity classification. A dataset for four different human activities generalized over six subjects was collected to train the 8-bit quantized CNN model. We obtained a subject-independent accuracy of 96% with the model size of 1.3 KB implemented on Cortex-R4F using CMSIS-NN framework.