The FireFly power monitoring and control board is work done by Yi Jiang and Bo Li.
In this project, we design and implement a remote switch control and power measurement system by using CMU Firefly wireless sensor board. The basic function for the system is that one central node can remotely switch on or off electronic devices and get the information, e.g. power, back from the switches. The basic design includes three parts: switch module, power measurement module and CMU Firefly board. The switch module uses an electrical relay to open/shut of the electrical appliance, e.g. TV, radio/audio, air conditioner, lamp, etc. The 110V hot wire is directly connected to our board and passed through a voltage transformer and current transformer to down convert voltage and current to the range in which the CMU Firefly board can operate. An accurate ac/dc converter is implemented to transform ac voltage/current to dc voltage/current so that CMU Firefly board can directly read from the pins. Then, the power data is calculated and wireless transmitted back to the central node. We design a single printed circuit board (PCB) to synthesize these three components in one board. A user-friendly interface is also implemented to simplify the operation of the system. In addition to the switch on/off function which the traditional remote control has, in our new designed system, switches can communicate and central control module, moreover, between adjacent switches if necessary. With more powerful sensors, more information, such as light intensity, temperature, motion, tension, or even chemical compound, can be integrated into our system. The microcontroller inside CMU Firefly wireless board can perform powerful functions, for example, power control, monitoring and alert in our case. The functions can also be extended to communication, smart control program, or smart detection/alert system. Furthermore, this system is based on wireless sensor network; it can be easily re-programmed, re-configured, and highly flexible for different environments. All this properties can lead to potentially industrial application of our designed systems. This prototype of our system is demonstrated by 4-node network in which each node control a 40W lamp. The demonstration shows that central node can
wirelessly control the four lamps individually and the accurate power from each of the node is transmitted back instantaneously. The functions such as power-save and autoswitch pattern are also implemented. The power measurement ranges from 10W to 1000W, which is suitable for most industrial electrical system.