Getting WIFI to PR2-Lite Reliably

WIFI signal strength can vary a lot in different locations of a house. The garage can be especially troublesome. We first installed a WIFI router at PR2-Lite, giving multiple developers access to the robot. However, the developers’ computers could not access the Internet via WIFI anymore. Then we run an Ethernet cable from the robot WIFI router to a PC, which had better WIFI connectivity to the home WIFI router. The PC acts a router between the home WIFI network and the “robot WIFI/wired” network. This arrangement worked well when the robot is not moving around too much because PR2-Lite was tied to a fixed computer.

We later tried to use dual band WIFI, which has much more bandwidth the 2.4GHz 11g WIFI and is supposed to have stronger signal because of the better antenna design of the dual band WIFI router. However, the USB dual band WIFI does not support Linux well. Therefore, we decided to give up this idea and went for a simple WIFI repeater.

D-link makes a small travel WIFI repeater, DIR-505, This repeater is very small and the only thing it needs is AC power.

It has three modes of operation, repeater, AP router, WiFi hotspot. Both the repeater mode and the WiFi hotspot mode will allow PR2-Lite to connect through DIR-505 to the home WIFI router to the Internet and allow multiple people to access the robot. We are using the repeater mode. This mode is simple. All the client computers including PR2-Lite will connect to the AP router of the same name as the home AP WIFI router. There is no change in the client computers configuration. If the DIR-505 repeater is not there and the home WIFI AP is strong enough. Every device can be connected via the home AP router. If the WIFI signal is weak in some locations, place the DIR-505 repeater somewhere between the home AP and the weak signal spot. The computers at the weak signal spot can access the DIR-505 and then go to the home AP WIFI router. No change in the client side. If we move the robot to the garage, we just need to place the DIR-505 somewhere near the garage door inside the house, the WIFI signal from the home AP router can reach the garage. This arrangement so far works fine.

There is another possibility. We can use a better antenna at the USB wifi plugin to the robot. We did not try this one because the small repeater seems to be working and is not inconvenient.

Written by Frank Ou


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