## 11 Hardware and Testbeds
### Camera Motes
The MeshEye mote has an Atmel AT91 SAM7S microcontroller board with 64 KB SRAM and 256 KB Flash memory, and the mote can host up to eight kilopixel imagers (Agilent ADNS-3060) and one VGA camera module (Agilent ADCM-2700). The wireless communication module uses CC2420 2.4 GHz IEEE 802.15.4 RF transceiver that can support up to 250 Kbit/s. Although the supported data rate is not high enough for multimedia streaming, the authors show that it is still possible by conducting in-node intermediate-level visual processing for efficient image compression and/or descriptive representations (such as axis projection, color histogram, or object shape). Also the authors present a basic power model that estimates the energy consumed in different operation modes by the battery-powered MeshEye mote. In [100] the design, implementation, and performance of video-based sensor networking architecture using visual sensor platform (called Panoptes) are introduced for delivering high quality video over 802.11 wireless networks. The initial developed hardware platform of Panoptes was the Applied Data Bitsy board utilizing the Intel StrongARM 206-MHz embedded processor connected with Logitech 3000 video camera via USB. Because of the limitations found by using this design such as slow video capturing, low processing power, high power consumption, and small available memory, the authors prefer to use Crossbow Stargate platform that has twice processing power more than the Bitsy board, consumes less power, and has smaller size. The second design of Panoptes node based on Stargate platform offers video capturing at reasonable frame rate (more than 15 fps) using Logitech 3,000 pro webcam. After video capturing, the software module in Panoptes provides video frame compression, both spatially and temporally, using JPEG, differential JPEG, and conditional replenishment. Also the software module in Panoptes provides other functionalities such filtering for dropping similar video frames, buffering management, and adaptation for network status. These functionalities can be accessed simply by function calls based on Python language by which the user can chose the preferred algorithm or method in each subcomponent (e.g., selecting compression algorithm or filtering method) at the run time without the need of manually reprogramming the nodes. At the end, the authors show the implementation and performance of a video aggregation application and some algorithms (such as prioritizing buffer management algorithm and bit-mapping algorithm for video querying) using Panoptes nodes. As an example of medium-resolution camera mote, an embedded camera mote platform [14] based on Fox board has been introduced for wireless multimedia sensor network applications. The designed platform has several sensors including GPS positioning receiver, current consumption sensor, and image sensor beside the wireless transceiver. The Fox board LX416 has 100 MHz CPU, 4 MB Flash, and 16 MB of RAM running GNU/Linux as operating system and because of these capabilities it is attended to be use for high-level device of multi-tier model. The platform can be connected via USB ports with webcam (QuickCam Zoom or Labtec Webcam) and Bluetooth dongle. The designed platform is using Bluetooth (IEEE 802.15) for data transmission, rather than 802.11 comparing to other high-level platforms like Panoptes or the one used in SensEye, because of the availability of USB-Bluetooth dongles, open-source software support and moderate power consumption. The current consumption sensor is used as an energy analyzer to study energy consumption of nodes during image transmission and it is shown in the experimental results that image grabbing and transmission needs more power than image routing. The work in [15] proposes the design of a wireless video sensor node, called MicrelEye, for video processing and image classification in wireless multimedia sensor networks. The device is equipped with a VGA CMOS (OV7640 from Omnivision) image sensor, a reconfigurable processing engine, and a Blue tooth 100m transceiver.