## 11 Hardware and Testbeds
### Camera Motes
So, CPLD acts as a lightweight frame grabber to provide on-demand access to high speed clocking at capture time and perform a limited amount of image processing such as background subtraction or frame differentiation. Cyclops firmware is written in nesC language and runs under TinyOS operating system. In addition to the libraries provided by TinyOS, Cyclops also provides primitive structural libraries (such as matrix operation libraries or histogram libraries) and advanced or high-level algorithms libraries (such as coordinate conversion and background subtraction). The authors show in the performance analysis that Cyclops is a low power device and its energy consumption depends on the power consumption of different states (such as image capturing, memory access, micro-controller processing, sleep _etc._) and their time duration as well as on the input image size and the ambient light intensity. FireFly Mosaic, a vision-enabled wireless sensor platform and image processing framework presented in [107], uses camera motes consisting of FireFly wireless node coupled with a CMUcam3 camera sensor. The FireFly nodes run the Nano-RK real-time operating system and communicate wirelessly using the RT-link collision-free TDMA-based protocol. FireFly Mosaic is designed to be low-cost, energy efficient, and scalable compared to the centralized wireless webcam-based solution. The used RT-link TDMA-based link wireless communication provides tight global time synchronization to prevent collisions and save energy while Nano-RK operating system provides hooks for globally synchronized  
Figure 6: Examples of Camera Mote Platforms. task processing and camera frame capturing. While the network communication relies on TDMA-based link layer, the internal communication between the camera and the wireless node is based on the Serial Line IP (SLIP). The CMUcam3 camera of FireFly Mosaic consists of CMOS (OmniVision OV6620) camera ship capable of capturing fifty 352 \(\times\) 288 color images per second, frame buffer (Averlogic AL440b FIFO), and 23-bit (LPC2106 ARM7 TDMI) microcontroller running at 60 MHz with built-in 64 KB RAM and 128 KB Flash memory. Also CMUcam3 has four on-chip servo controller outputs which can be used to actuate a pan-tilt device. In the other hand, FireFly sensor node has a low-power ATMEL ATmega 1281 8-bit processor with 8 KB RAM and 128 KB Flash memory, connected with Chipcon CC2420 802.15.4 radio capable of transmitting a 250 Kbps for up to 100 meters. CMUcam3 is an open-source camera comes with several libraries (named CC3) and example applications such as JPEG compression, frame differencing, color tracking, convolutions, edge detection, connected components analysis, and a face detector. This several image processing algorithms can be run at the source and only the results may be sent over the multi-hop wireless channel to the FireFly gateway. CMUcam3 can be also interfaced with other type of sensor nodes such as TolesB and Tmote Sky motes running different operating systems. Wica [108] is another camera more designed for wireless multimedia sensor network. The wireless camera mote is based on an SIMD (Single Instruction Multiple Data) video-analysis processor and an 8051 micro-controller as a local host, and it is using the IEEE 802.15.4 standard (ZigBee) for its wireless communication. The camera consists basically of four components: one or two VGA color image sensors, an SIMD processor for low-level image processing, a general purpose processor for intermediate and high-level processing, and control and communication module. The SIMD processor is of type IC3D from Philips'Xetal and it consists of Linear Processor Array (LPA) with 320 RISC processors. 8051 controller from ATMEL is used as a general purpose processor and it includes 1.79 MB RAM, 64 KB Flash, and 2 KB EEPROM to store the parameters and instruction code for IC3D processor. Both processors are coupled using a 128 KB dual port RAM that enables them to work in a shared workspace asynchronously.