Hi Alan, > What I currently take in club gliders is a simple open source Chinese car > GPS and I derive 5 volts via a car charger. [AS SEEN IN THE ATTACHED > PICTURE]. > One slightly OTT comment: using a car charger is, of course, a good way to go, but you might want to modify that a bit over the next winter because some pilots I know aren't really happy with the cigarette lighter connector on the 12v end of the charger. I did what I'm about to describe back in 2004 and its been working well ever since.
As I said, the problem is the unreliability of the contacts in the cigarette lighter plug. If you've ever taken one apart and peered at the bits you'll quickly wonder how it can ever make a reliable connection and thats without considering that the spring in the centre pin is doing its best to make the plug jump out of its socket. The solution is to get a charger off eBay and take it apart. You can use any car charger provided it has the right type of mini-USB connector: there are at least three incompatible types, but the one used with iPAQ PDAs and PNAs seems to fit most other PNA devices too. The output voltage will be fine because all USB connectors are required to provide 5v at either 800 or 1000 mA depending on whether they meet the USB 1.0 or 2.0 specification. I prefer iPAQ chargers because the older ones, e.g. for iPAQ 36xx PDAs, provide up to 1400 mA. If you take the charger apart you'll find a tiny switch-mode 12v->5v converter inside. Keep that and the attached USB cable. Unsolder the 12v line from the cigarette lighter contacts and discard them and the case. Visit Maplins/Dick Smith/Radio shack/Farrells/RS and get a small plastic or metal box to hold the converter circuit. Metal or plastic with a metallic shield sprayed inside are best because some of these converters generate a lot of RF noise. Solder a 12v lead to the converter with a connector at the other end that suits your glider wiring - I like XLR plugs. Mount the converter inside the small box (I hold mine in place with sticky foam Pritt Pads) and push the LED into a press-fit hole drilled in the case where you can see it when the box is mounted behind your panel. Fit grommets round the exit holes for the 5v and 12v cables and you're done. In fact I use a rather bigger box with XLR connectors for 12v in and 12v out, for my SDI C4, plus a set of D-9 sockets, each providing a direct data and/or power connection to an instrument (C4, EW logger, PNA, GPS,...) with all the interconnections soldered between the D-9 sockets inside the box. The 12->5v converter is also in this box. This arrangement has two advantages: (1) the wiring behind the panel is neat and tidy and (2) I can take the connector box and instruments out of the panel and run them up on the bench for troubleshooting or testing if/when I replace an instrument. An alternative solution, and better if you're flying club gliders though a bit more expensive, is to buy a 3000 or 4000 mAh external battery, the sort sold for charging a mobile phone, and fly with this permanently plugged into the PNA. Most PNAs have an 800 mAH internal battery that's good for 2.5 hours, so simply using a 3000 mAh external battery will add almost 10 hours to its run time. Martin ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Xcsoar-user mailing list Xcsoar-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xcsoar-user
