XLAPRS New Hardware
Description of the new system...The new hardware I am working on now (Mar 2003) is much more compact and low powered than my first try. Parts I'm using:
- Via EPIA 5000 mini-ITX board (no cpu fan)
- 256MB PC133 SDRAM
- 60W DC-DC converter from mini-box.com
- IBM 40GB laptop hard drive
- KISS TNC from W2FS (replaces KPC-3)
- Yaesu FT1500 2m tranciever
- Moxa SmartIO 4-port PCI serial card (ebay -- cheap!)
- Motorola M12 GPS (replaces Garmin GPS3+)
With the more efficient power supply, low-power board/CPU, and switch to a dumb 4-port serial card (instead of the 8-port intelligent rocketport), I have power usage down to just over 1A at 12v -- 7 times less than before, and that includes all the pieces but the display. I'm very happy with the power consumption of the new hardware.
18-apr-03Got some major software work finished:
- LCD is up and running
- multiple "screen" handling code done (threading sync and user command routing/focus control)
- Implemented some display widgets, including a compass widget and a differential generic text field widget (only redraws teh value when the value has changed)
- Implemented GPS info screen
- Implemented APRS station list screen, with scrolling of data columns, and filtering/sorting of APRS stations
- SmartBeaconing implemented
- Config editing screen done, complete with ability to write config file out to the hard drive
- APRS WX station parsing
- APRS station detail screen (one station taking entire LCD), including WX display
- Test drive! Particularly SmartBeaconing...
- APRS messaging (low priority)
- Packet dupe detection (could lead to digipeater functionality, too)
25-mar-03M12 and power distribution block are mounted now. From now on I'm just going to dump pictures into a section of my picture gallery.
Code status: I've written some code to fix the altitude output of the M12 GPS receiver; it only outputs GPS altitude so I had to calculate "geoidal separation" to get more useful MSL altitude. I also started work on getting the Matrix Orbital display code moved to Python; the serial port setup needed some hacking (the display wants software flow control but only in one direction, and not with standard XON/XOFF characters).
02-mar-03TNC mounted in box, M12 gps not mounted yet. Switched to flexible PCI riser (from Adex Electronics) also.
22-feb-03I'm now using a KISS TNC from W2FS. KISS mode is much easier to deal with from a softwre standpoint than all the KPC-3 terminal user interface gook. A couple evenings looking though the KISS and AX25 specs and I've got TX and RX working. As a bonus, the new TNC is about 1/3 the price of a KPC-3, uses less power, and is smaller!
14-feb-03I've taken some more detailed power measurements of all my new components. All measurements at 13.3-13.4vdc
MB + serial + HD in Linux, idle 0.847 A F1500 idle, backlight off, no RX 0.230 A GPS locked, no backlight 0.045 A KPC-3 0.030 A Total power during idle w/out display 1.12 A ~ <15W Surge power on computer startup (250us) 3.971 AThe mini-box DC-DC supply was a big help in getting power consumption down -- my old 250W 12v ATX PS used almost an amp just to power its cooling fan and keep itself regulating.
Pics of new hardware in development
Have a basic case now. 17 x 10 x 3 inch aluminum box, mobo mounted with standoffs, hard drive hung by one side (need some foam rubber to cushion it). There's room under the HD for the OEM GPS board I want to get to replace the Garmin that's in here now. TNC is buried on the lower right under the GPS. I left room for a CF card adaptor on the left (over the HD ribbon cable). 2m radio is outside this box for RF sanity.
Hopefully there's enough air in here to keep temperatures sane while dissapating 15W of heat into the walls of the case (after I put the lid on)...
Side view 1
Side view 2
DMM, HD, computer, TNC, radio, etc.