Last updated: 15 February 2005
Sent: Tuesday, February 15, 2005 03:53:30 From: Martin Larsen (firstname.lastname@example.org) After having bought an ETX-90 a few weeks ago, I made myself a serial connection cable using information on Weasner's site. I soon discovered the need for powering the Autostar without setting up the mount. Again I found lots of useful info on the site, and I made a connection box by simply mounting a DC female connector in an Ethernet (RJ 45) wall box as seen on picture 1. That made it easy to power the Autostar handbox from any 12 V DC power source. Then I got an idea! I already used a cheap USB lamp for lighting up the notebook's keyboard in the dark (tip: remove the glass and put some red cellophane inside - or just wrap it around the lamp), and if the USB port could power the quite bright lamp, why shouldn't it be able to power the Autostar? Of course, the USB only supplies 5 V, but as seen on this page http://www.weasner.com/etx/autostar/as_power2.html Autostar runs happily on 5 V. And this page http://www.weasner.com/etx/autostar/as_power2.html states that Autostar draws less than 100 mA, whereas the USB specs allow for 500 mA drawn from the port, so it seemed quite plausible. I then took a spare USB cable, cut one end and mounted a DC plug instead. Eureka! With the USB plug connected to the PC and the DC plug in my homemade connector box, I was able to control and update the Autostar without an external power source. The arrangement (without the notebook) is seen on picture 2.
Inside a USB cable the power lines are red and black (for plus and minus) so it's really simple to make the cable. Just cut off the other two wires as you don't need them. NOTE: The 500 mA allowed on the USB port is shared among all your USB equipment. So if you use a really bright USB lamp, and a USB mouse and .... you name it .... you *might* run into trouble! It works great for me, though :-) Martin Larsen
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