## 8 Performance Test
### Power Consumption  
Although we have provided every device with batteries and solar panels that allow charging the batteries when the sun is shining, we have studied the energy consumption of every device. In this section we provide the power consumption for all devices used in our deployment.  
Table 3 shows the power consumption for each device depending on its state. The device that consumes more power is the Cisco Aironet 350 Bridge and the one that consumes less power (but if it is not moving) is the Wireless IP Camera (D-Link DCS-5220). On the other hand, we can observe that the wireless IP Camera does not have \"Idle mode\", so it will be sending images all the time. So it has higher power consumption.  
In order to show the power consumption of the devices shown in table 2 over time, we consider that the circuit used to regulate the battery needed for all the devices consumes the same energy and it is quite low compared with the energy consumed by the devices. The energy consumed by the sensor is also negligible compared with the energy wasted by the chips. Taking into account measurements taken in [31], we suppose that a wireless link spends 70 percent of the time idle (in standby mode), 20 percent of the time receiving, and 10 percent of the time transmitting. Figure 20 shows the power  
Figure 19: Packets per second when there is an alarm.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Device** & **Idle Mode** & **Wireless ON** & **Transmitting or Receiving** \\ \hline _Linksys_ & 2,400 mW & 3,240 mW & 3,360 mW \\ _WRT54 GL v.1.1_ & & & \\ _Cisco Aironet_ & 4,320 mW & 5,760 mW & 6,240 mW \\ _350 Bridge_ & & & \\ _D-Link_ & – & 2,640 mW (video: 176x144) & 2,640 mW (video: 176x144) \\ _DCS-5220_ & & 2,760 mW (video: 320x240) & 2,760 mW (video: 320x240) \\  & & 3,000 mW (video: 640x480) & 3,000 mW (video: 640x480) \\  & & & 5,280 mW (moving the camera) \\ \hline \end{tabular}
\end{table}
Table 3: Devices consumption.  
consumption over time by the devices shown in Table 2. The device that consumes more power in our system is the Cisco Aironet (c) 350 Bridge, which is used as Non-root Access Points and as root Access Points. The worst case for the IP Camera is when it is always moving. It does not happen too much. The best cases are when the multisensor and the IP Camera transmit with a video quality of \(176\times 144\) at 25 fps.  
In order to simulate the total amount of time that a multisensor will be able to be transmitting and receiving with a totally charged battery, we take into account the considerations and values provided in [32] by [PERSON] _et al_. The transmission and the reception energy are given by the expressions 4 and 5:  
\[E_{Tx}(k,r)=\Big{(}E_{Tx}+E_{amp}r^{2}\Big{)}k \tag{4}\]  
\[E_{Rx}(k)=E_{Rx}\cdot k \tag{5}\]  
where \(k\) is the number of bits sent in the packet, \(E_{Tx}=E_{Rx}=50\) nJ/bit, \(E_{amp}=100\) pJ/b/m\({}^{2}\).  
Taking into account the measurements taken in section 8.3, the multisensors send an average value of 1,175 bits per packet. Now, we can estimate the power consumption because of the packets transmitted and received by all multisensors over time. The multisensor is supplied by a 12 V 24 Ah battery with a solar panel, but we switch off the solar panel (no sun shinning for many days) in order to know its lifetime. We have considered the circuit energy consumption, the data processing energy consumption, the energy, when it is reading and writing in the memory, and the energy consumed by the physical sensor as being close to zero because the energy consumed is very little compared with that consumed by the nodes due to all the packets sent and received. Figure 21 shows the energy consumption of a multisensor in the worst case (always transmitting or receiving without any time being in the idle mode). The multisensor will be able to be in this hard mode for more than 16 hours. Then, the battery has to be charged using the solar panel  
Figure 20: Power consumption.