wearable + mobile dev.
current ProjectTxoom system.
(include notes from hw meeting on 20020806 + brief summary of design descisions/options/etc+ –nik gaffney)
Work is continuing on a new wireless sensor aquisition system, to hopefully overcome the problems found with all the previous systems. The current version is still built on a series of comprimises between price,availability,elegance,wirelessness and flexibility, however it should be edging towards something better.
Hardware setup
Software setup
calibration + sensing code (gpio →
OSC )
details can be found in the techspec (linked from Project Txoom System ), code is in cvs, and notes can be found in the Cerf Notes node.
datarates.
sampling periodicity: ~10ms/vector or as close to 4ms/point as possible (100-250Hz)
latency: should be as low as possible. if a vector takes too long to store, send points.
thruput: accelerometer data is single byte (8bit) per point.
calulations for 2x3d acceleromters (for reference)
8bits x 6axis = 48bits/0.004s = 12kbps (at 4ms sampling rate) per player.
8bits x 6axis = 48bits/0.01s = 4800bps (at 10ms sampling rate) per player.
8bits x 6axis = 48bits/0.02s = 2400bps (at 20ms sampling rate) per player.
(note: raw data, no correction, or stop bits)
players | 4ms | 10ms | 20ms |
1 | 12k | 4800 | 2400 |
2 | 24k | 9600 | 4800 |
3 | 36k | 14.4k | 7200 |
4 | 48k | 19.2k | 9600 |
5 | 60k | 24k | 12k |
{{sensor_monitor.png}}
setup + config notes for CERF/CEED based system
see also CerfNotes for more details
wired connection
prerequisites
attach ethernet cable to the ceed box
powerup ceed
wait for a while,
find its ip
run nmap or similar to find which ip# it has …
eg. # nmap -sP 192.168.254.1-15
check which ips are in use before + after turning the ceed on
check there is something listening to port 5333 on the host machine (eg, 'oz', 'nc -lup 5333' or an OSC capable program)
connect to the ceed # ssh -lroot 10.0.0.x
load the adxl module # insmod adxl.o
run the sensor program in test mode # ./operate -c debug.conf -h <host.ip>
check which chanels are active
edit the operate.conf file if required.
run the sensor program # ./operate -h <host.ip>
sit back + relax
wireless connection
make sure the base station is active
check SSID set to f0am (using ap-config under GNU/Linux)
contine as above from the 'powerup ceed' step
setup + config notes for IPaq based system
see also IPaq Notes for more details
these notes are meant as a quick guide to setting up the ipaq + sensor sets for the tgarden/tx0om system(s). insprired by my lack of memory, and the fact that teh wearables can be fickle creatures, .. .
so,
connect access point to network
turn on ipaq
press the “Q” button to boot linux
open 'Utilities → Input Methods → Xkbd' by clicking on the screen
open 'Root' window by clicking on the screen
(optional) type 'bash' for smoother shell interaction
type 'ifconfig' and see if there is an entry for 'wlan0'
type 'pump' and check ifconfig again.
if there is no entry for 'wlan0' device, type…
ifconfig wlan0 192.168.254.3 netmask 255.255.255.0 up
(substituting the suitable ip# and mask for the network)
route add default gw 192.168.254.1
(or whatever the ip# of the access point is)
type 'route' and check the routing table is correct
dont bother with /etc/resolv.conf unless you must
it should now be possible to connect to the ipaq using ssh
now, the sensors…
make sure the stamp is charged + sensors connected
on the ipaq, enter 'cat /dev/ttySA0' to display data comming in the serial port
connect the stamp to the ipaq serial port
sit back + watch the numbers,. ..
if there are no numbers, there is a problem (find it + continue)
calibrating…
cd to 'sensors' directory of $HOME
calibrate -c &<sensor number>
check the min + max values for each sensor channel
operating…
see also: Mobile Computing, Wearable Computing, Sensor Technology, Human Interface System