I'd like to build a small hardware (the size of a big watch) capable of sending continuous wifi data. Right now I'm thinking of using a lilypad with Polymer Lithium Ion Batteries - 100mAh, and LilyPad LiPower, it's the smallest i could think of, but I'm open to suggestion ^_^.
I have a couple of questions:
how long do you think the battery will last?
how could i implement something that enables me to recharge it like a normal cellphone?
I have (coming soon!) a texas instruments programmable sportswatch with wireless built in. It's not wifi but it was a pretty reasonable price and maybe it could do what you need.
There are some SDIO WiFi cards out there that might work: I see that some of them have Linux drivers. But they seem to be pretty power-hungry, based on comments I've seen about PDA battery life.
You may be happier looking at some of the simpler radios like the ones built into that TI watch.
thanks guys.
I'm a bit new to Arduino, so maybe I wasn't clear enough in my post...
I don't want to build a watch, instead I'd like to build a small hardware that can be dressed like a watch. This is how it's gonna look like:
arduino
accelerometer
battery
wireless transmitter (bluetooth, radio, wifi IR)
My problems reside on:
the smallest possible form factor (as said, like a watch)
latency of continuous data being trasmitted (maybe bluetooth or IR can be ok? I yet don't know)
battery duration (single charge duration)
that's it.
hope this clarifies my previous post
thanks again!
guys, i must learn to wait a little bit before posting :-X
i checked the items carefully, and i must say that that watch perfectly fits all my needs. I didn't know it had an accelerometer inside!
i have just few questions, for i couldn't find any documentation online:
if i have two watches communicating with the same computer software, do you think it's ok?
(i mean... can i have two different IDs so that the software recognizes them as two different sources? and, most of all, will the two radiofrequency mess with each other?)
will IR be ok for accelerometer datas? isn't there too much latency?
do you think they'll be able to communicate with programs like MAX/MSP?
do you have an idea of how much the battery will last?
if i have two watches communicating with the same computer software, do you think it's ok?
Yes, but you'll need to set up some sort of protocol that enables them to take turns communicating (either have the central system poll them, or have them retry after collisions when they both try to talk at once). There are examples of how to do this available on the net.
will IR be ok for accelerometer datas?
Probably not: IR requires line-of-sight communications to be reliable. If you're sending accelerometer data from a watch that someone is wearing, it probably means the watch is moving around in a way that keeps the IR emitter from being aimed steadily at a receiver.