Journal of Engineering Science and Technology Vol. 13, No. 2 (2018) 473 - 488 © School of Engineering, Taylor’s University 473 AN INVESTIGATION OF THE POWER CONSUMPTION OF 315 MHz RF ASK TRANSMITTER AND RECEIVER MODULES FOR WIRELESS SENSOR NETWORK NODE ALI M. ABDAL-KADHIM*, KOK S. LEONG Faculty of Electronic and Computer Engineering, Universiti Teknikal Malaysia Melaka (UTeM), Durian Tunggal, Melaka, Malaysia *Corresponding Author: ali.challenger89@yahoo.com Abstract Sensor node in WSNs is the major bottle neck that restricts WSNs realization due to limited processing, communication ability and power sources. The communication or wireless transmission unit has noticeable effects on wireless sensor node system, since its power consumption is dependent on the transferred data package size. This research paper presents evaluation and characterization of transmission time, minimum amount of operating voltage and current, and hence the power required to transmit certain size packets of data of an off-shelf RF ASK 315 MHz wireless module. A microcontroller with the VirtualWire library was used to provide data to the transmitter module and transmit it to the receiver, located 2 m apart, with transmitting rate of 2 kbit/s. The experimental outcome showed that the tested module would need 50 ms with 0.3 mW in order to transmit a byte of data. The transmission time increased proportionally with the data package size. Meanwhile, the transmission power increased in logarithmic manner with the data package size. Keywords: 315 MHz RF module power consumption, Transmission time, Wireless sensor node, Energy harvesting. 1. Introduction Wireless Sensor Networks (WSNs) play a major role in the research field of multi-hop wireless networks, ranging from environmental and structural monitoring, to border security and human health control. Researches relative to this field cover a wide spectrum of topics, leading to advancement in node hardware, protocol stack design, localization and tracking techniques, and energy management [1]. Researches on WSNs are driven (and somewhat limited) by a