20 Jun 2011 motters   » (Master)

Fitted a D525MW mini-ITX motherboard to the robot, and installed Linux Mint 11 and ROS onto a 16GB USB flash drive.

https://sluggish.homelinux.net/wiki/File:Mini-itx1.jpg

This makes a good minimalist onboard computer, and was considerably cheaper than buying an equivalent netbook. To set everything up I connected a keyboard, mouse and monitor as usual, but once the motherboard was installed on the robot it only requires the wifi adaptor and USB drive to be connected. I deliberately didn't want to use a hard drive (although I have a couple of old ones available) based upon bad experiences with mobile robots and hard drives in the past. Also I reused some old PC speakers which havn't seen the light of day for probably more than a decade. You never know when such things may come in useful.

https://sluggish.homelinux.net/images/f/f2/Grok2_electrical2.jpg

One trick with running the OS from a flash disk is to delete the existing casper-rw file, then create a partition labelled casper-rw. This enabled me to make use of the full USB drive, rather than being limited to 4GB of persistent storage.

The user interface of the robot currently consists of buttons and audio. When you press buttons the robot says something appropriate, so it's not so much a graphical user interface as an audio user interface. For the sorts of tasks I envisage the robot doing this is quite adequate, although if more elaborate instructions were needed I could add a small screen of some sort (finances permitting).

With the robot running I can then use either VNC or ssh to debug code or run different programs.

There's some tidying up remaining to be done on the head of the robot, Since the Kinect sensor's circuit boards are exposed and vulnerable to collisions. I'll devise some sort of covering to go over that.

An initial localising test run done earlier today indicates that everything seems to be working as expected, and the new computer can handle the processing demand. Even for a relatively simple differential drive robot like this there are a considerable number of electrical connections, and there's always some degree of trepidation over whether I've connected them back in the right order. Labelling everything helps a lot.

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