Bluetooth GPS on the mini2440 with GPSd
For a long time i've had a SiRF 3 bluetooth GPS which i've just connected to the mini2440 using a ludicrously cheap USB bluetooth adapter from DealExtreme. Including shipping it cost £1.38 delivered!! Here's what you get for your money:
The chip is a Conwise CW6626. Anyway, what matters most is that if you have bluetooth configured it works out of the box!
Connecting to the GPS is easy. First check the interface:
hciconfig -a
If it says down bring it up:
hciconfig hci0 up
After executing the above I got the following:
root@mini2440:~# hciconfig -a
hci0: Type: USB
BD Address: 00:15:83:15:A3:10 ACL MTU: 672:3 SCO MTU: 128:2
UP RUNNING
RX bytes:348 acl:0 sco:0 events:11 errors:0
TX bytes:38 acl:0 sco:0 commands:11 errors:0
Features: 0xff 0x3e 0x85 0x30 0x18 0x18 0x00 0x00
Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3
Link policy:
Link mode: SLAVE ACCEPT
Name: ''
Class: 0x000208
Service Classes: Unspecified
Device Class: Phone, Cordless
HCI Ver: 2.0 (0x3) HCI Rev: 0xc5c LMP Ver: 2.0 (0x3) LMP Subver: 0xc5c
Manufacturer: Cambridge Silicon Radio (10)
Now turn your GPS on and do a scan:
root@mini2440:~# hcitool scan
Scanning ...
00:0D:B5:32:2C:02 BT-GPS-322C02
Now fill in /etc/bluetooth/rfcomm.conf with the details. Here's mine:
#
# RFCOMM configuration file.
#
rfcomm0 {
# Automatically bind the device at startup
bind yes;
# Bluetooth address of the device
device 00:0D:B5:32:2C:02;
# RFCOMM channel for the connection
channel 1;
# Description of the connection
comment "BT-GPS-322C02";
}
Next bind the device:
rfcomm bind rfcomm0
And check the device output using:
cat /dev/rfcomm0
Next i bitbaked gpsd, by simply typing:
bitbake gpsd
In my OE installation (see the various posts about setting this up).
Once this builds you can install the appropriate ipks. From memory I think i installed the following:
gpsd_2.39-r0.5_armv4t.ipk
gpsd-static_2.39-r0.5_armv4t.ipk
gpsd-gpsctl_2.39-r0.5_armv4t.ipk
gps-utils_2.39-r0.5_armv4t.ipk
libgps18_2.39-r0.5_armv4t.ipk
This pulled in a whole load of other packages. Next you can start gpsd by typing:
gpsd /dev/rfcomm0
And monitor the output using:
gpsmon
If all has gone well you should get a text output of the parsed NMEA data:
Anyway..that's just the tip of the iceburg. If you want to learn more have a look at the gpsd website and the bluetooth page i have based this post on.