On Tuesday 05 September 2006 07:05 pm, Rony wrote: > krishnakant Mane wrote: > > hi, > > yes, central server is the way to go this is what I was advicing > > from quite some time. > > Central server makes use of a computer and needs underground wiring > or expensive wireless network. Plus a power consumption of over 300 > watts. Local tiny broadcaster circuits are cost effective and > maintainence free. Install and forget. The choice is now FM or WLAN > or Bluetooth as per Dinesh's suggestion.
U have mis understood. The Central server is not connected in any way to the rails - atleast initially. After the user hears the info, particularly the url "prabhedevi c" (alongwith instructions abt local landmarks) he will enter this url, http://www.mylocation.org/mumbai/prabhadevi/c/ MYDESTINATION in HIS preferred device, ideally a gprs enabld phone (possibly midp compliant). This will hit the server hosting mylocation.org and serve an ogg (mp3??) file which will play on his phone. No wiring, no cable. Wlan / bluetooth is out because of price associated with a relatively big processor and protocol stack. > > Why are we looking at solar panels and batteries? Like street > lights, these could be powered by the municipal electricity or > traffic signal posts. Maybe a battery backup for power breakdowns. Because it will cost Rs.10000/- per meter of digging and aquaint you serfs with all the Royalnesses in the fiefdom of BMC. As it is they might cast a spell on you and make your project into a frog. > > We also need to check out power consumptions of all the 3 devices > mentioned above for a TX. range of 5 feet only, not 100 feet. less than a watt for fm+mp3 player. 7 to 8 watts for Wlan. 3+ watts for bluetooth - u cant just stick in a blutooth with two wires u have to process events from the bluetooth device and write out a digital stream to it's input, so while the bluetooth device itself will be less tahn 500mw the rest of the electronics to drive it will suck power. > What about a cheap laser diode pumping high density packets into a > receiver. The rail has a hollow docking port to simply place the > receiver's probe into it for a few seconds, so no shake problem. A > beep will tell the user that data is transferred. This will make it > cheap and will also function as the user position aligner. Forget about finding a hole in a high footfall area. The laser diode will cost more than the entire fm and bluetooth setup put together. even if u used el cheapo infrared u are still mandating an esoteric device for the end user. -- Rgds JTD -- http://mm.glug-bom.org/mailman/listinfo/linuxers
