Sunday, July 21, 2013

BeagleBone Black - First Impressions and Astronomical CCD's

Bought a BeagleBone Black from element14 last week, cost was S$ 66.70.  Since then element14 has lowered the price to S$ 56.95.  The BBB is an Arduino-sized Linux machine with a 1GHz Texas Instruments Sitara SoC, 512MB of RAM, 2GB of onboard eMMC NAND flash with the Angstrom Linux distribution, a micro-SD card slot, 10/100 Ethernet, a regular-sized USB host port, a mini-USB slave port, and a micro-HDMI port for video output.


So far I haven't used it with the micro-HDMI port for lack of the proper adapters, I've wired it up to my access point (which has a bunch of Ethernet ports) and powered it off an iPad charger with a USB cable.  I have tried both the latest version of Angstrom Linux, and Ubuntu 12.04 LTS for the BB.   Angstrom is a fairly strange distribution, as it's based on some OpenWRT tools. Ubuntu is much more predictable to a desktop Linux user; however it is missing Chromium and the OpenCV libraries, which are both bundled with Angstrom.

I got a 16GB Transcend micro-SD card (about S$ 17). The onboard eMMC is too small to install a full OS. Currently there is a bug or feature limitation on the BBB where, if you boot off the eMMC, the micro-SD card is not visible; so the only way to use the micro-SD is to put both the OS and the separate file system on it. To get a full OS (e.g. I installed KStars on Ubuntu) you really need a micro-SD card.  16GB seems to be the sweet spot in terms of price/storage.

I've had some ambitions of using the BBB as a stand-alone astronomical imaging controller, e.g. when connected to a telescope and two cameras, it would perform telescope control, auto-guiding, and image capture.  I have a Meade DSI lying around, and with some Makefile kung fu I managed to get the Meade Deep Sky Imager code for Linux to compile on Angstrom.  I need to get my hands on the Meade DSI firmware, and see if I can get things working.

Supporting my QHY8 astronomical camera would be easier on Ubuntu (because the CCD software requires a Qt development environment) but I'll get to that later; I'm not even sure if my QHY8 is supported, since the CCD software specifies the QHY8L.  Tried changing the VID's in CCD but the QHY8 doesn't work.

1 comment:

CW Robertson said...

I liked the post. I have a 12" Meade and a 16" Meade, both LX-200s. Several years ago, the 16" got confused, and the scope headed for the pole, and the instrument package hit the forks. So I installed hall effect limit switches on the 16".

I plan on using a Beaglebone Black to measure the telescope angle with a 3 axis accelerometer. Use that to find the angle, then have the Beaglebone turn the scope off (open power relay) if the scope goes somewhere it shouldn't.

Started with Arduino, moved to a PI with Gertboard, but an pretty sure the beaglebone Black will gather the information, post the status on the webpage, and look for clouds.

Nice Post.
-C. W. Robertson
http://www.setec-observatory.org/