2008 design will use gumstix as main proc - with gumsense as wake-up device. It will wake up once a day at noon GMT for long range coms to UK. An ssh tunnel will let us login then from UK.
- ttyS0 - for probe coms/net
- ttyS1 - GSM/GPRS ? depends if rts/cts needed
- ttyS2 - for GPS (if needed) - will tell dGPS to start/stop recording
usb - usbnet to laptop?
GPIO - control BatV relays for GPS and GSM units (offboard if gumsense can't cope)
ADC used for BatV
I2C for a temp/hum sensor
Base box specs
Has these external connectors (pref Mil spec):
- GPS antenna TNC
- GSM antenna (wierd smb waterproof con - probably not so great after all)
- rs232+pwr to wired probe (mil)
- PWR in - from solar (mil)
- PWR in - from Wind (optional)
Note the MIL connectors are Amphenol plugs (MS3106A-14S-2P) with strain (97-3057-1007-1) plugging into 4 way socket (MS3102A-14S-2S). Expensive but the toughest we have ever used!
Base Box parts
- clean, reinforce/seal Peli box
- gumstix (in mini box)
- regulator for solar/wind
- 2-3 12AH 12V Batteries
- GND and BatV coupling
- 10W solar panel (on top of box) - uses windy's regulator
- wind generator
A script on the base is run when it wakes (mainly Python this time). This does something like:
if batV OK powercontrol gps on start GPS recording probejob: (ping all probes and store RSSIs) using probeping (fetch probe data) probegetdata (Write to files) put probes to sleep (if not done in above) basejobs: get base data (eg BatV, Temp) tarball new data onto flash complete gps job if it ran: stop GPS recording fetch gps file powercontrol gps off coms job: powercontrol coms on open GPRS coms - maybe wait for good signal with timeout startpppd try to send (rcp) all unsent data start ssh tunnel if stayup sleep for a while (allows remote access) close gprs ppd powercontrol coms off sleep (poweroff)
Format could be ext3 - without atime and possibly turning on "barriers" to make it more secure (see http://lwn.net/Articles/283161/). We have an industrial 1GB CF from sandisk in base. It needs certain directories to exist on it (queued archive data).
to use ext3 filesystem - we need "noatime,nodiratime"
In the end a specific vfat is needed - beware!
Both Iceland and Norway systems had some kind of CF errors eventually :-(