# Hardware

## XBee Series 2B Pro

The XBee Series 2B Pro is the networking hardware that we have been testing on the Milieu Bable so far. The XBee Series 2B Pro is great for our project because it supports the Zigbee networking protocol. It has an outdoor line-of-sight range of 2 miles and a data rate of 250 kbps \[1]. In terms of connecting our devices to ROS, we can use `rosserial` and a baud rate of 9600 to connect to the device's network. If you use the standard `rosserial` package, make sure that you use `rosserial_server` node instead of the `xbee_network` package to connect to the network. This is because `xbee_network` is only compatible with Series 1 XBee devices.

## Digi XBee-PRO 900HP RF Module

This device, also a member of the XBee family, is another radio we have researched but not yet tested. It supports a bandwidth of 200 kbps, like the XBee Series 2B Pro. However, what makes it an attractive option is that it provides a radio frequency of 900 mhz. The advantage of this frequency is that the radio signal has a larger range of 9 miles. Additionally, the signal is more resillient and can suffer much less from obstructions such as buildings. This reduces the need for a clear line-of-sight between two devices, and can provide for a more stable connection.

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## Citations

\[1] "XBee/XBee-PRO ZB RF Modules User Guide.", May, 2018, <https://www.digi.com/resources/documentation/digidocs/PDFs/90000976.pdf>.

\[2] C. B. Teja and H. Sharma, "Enhancement of UAV Performance Through Xbee Based Telemetry System Design," 2019 International Conference on Communication and Electronics Systems (ICCES), Coimbatore, India, 2019, pp. 1762-1765, doi: 10.1109/ICCES45898.2019.9002179.
