Multiple Cell Phones
Multiple Cell Phones
(OP)
Is there a way to have a large constellation of independant cell phones?
Example: You have a hundred sites that you want to gather information at certain times and email it in, but you don't want 100 monthly accounts. They could all have the same phone number. They would only call in.
What happens when someone inevitably, wrong number, dials that phone number?
What would happen if more then one phone emailed(called) in at the same same time.
Example: You have a hundred sites that you want to gather information at certain times and email it in, but you don't want 100 monthly accounts. They could all have the same phone number. They would only call in.
What happens when someone inevitably, wrong number, dials that phone number?
What would happen if more then one phone emailed(called) in at the same same time.





RE: Multiple Cell Phones
The phone company may be able to give you a reduced rate if you're involved in a worthy cause.
I assume you'd send simple text data that doesn't clog the phone system much.
Many cell providers have $10 per extra phone per month feature for up to 4 extra phones, so at a minimum, maybe it ends up being $15 per phone, or $1500 per month cost.
kch
RE: Multiple Cell Phones
rmw
RE: Multiple Cell Phones
A data system like for monitoring sewage levels around a town. You might need 50 or 60 but requiring 50 or 60 cell accounts would be a total show stopper.
rmw the type of info would be minimal in this example; identifier, time, depth. Five to 15 bytes. These would be sent to a standard email account for easy handling.
RE: Multiple Cell Phones
Sounds like something that if available commercially could be around $40 per transmitter and a $1k receiver.
Doesn't sound off the shelf though.
kch
RE: Multiple Cell Phones
Another choice is:
http:/
The blurb refers to "uplink pagers," but I couldn't much detail beyond that.
TTFN
RE: Multiple Cell Phones
http://www
http://www.villagesoft.com/wisk/technology.htm
TTFN
RE: Multiple Cell Phones
I have seen a system using a Tixi modem Link to Tixi, and was told that T-Mobile has an SMS only account program where you can buy small amounts of SMS messaging very cheaply for SCADA systems like this. The Tixi modem can convert inputs to SMS messages. There are undoubtedly other systems like it available, this is just the only one I have seen.
"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more."
Nikola Tesla
RE: Multiple Cell Phones
Further the example I gave while it does, I agree, fit the "relatively close together" discription. It is addressable by lots of off the shelf SCADA systems.
IRstuff; Thanks for the links I'll look into the RIM but I'm afraid that they will want $25/ month for a backwards capable pager.
The Apollo deally is again a local transmitter requiring me to put up and maintain an RF network. gaah!
Wisk is interesting but way too expensive. You can get cell phones at half the price. Then under pricing they say
besides software licensing fees you need wireless service fees. Which I realize must be paid but I'm trying to figure out how to reduce this to something reasonable for the scrawny amount of data I'm looking to pass.
jraef those Tixi are neat! But profoundly expensive.
Here's what I'm talking about.
htt
I want to do this, but add several features making the unit that plugs *into* the cellphone. But if each phone costs $20/month for an account and then $0.10/message a huge number of applications evaporate.
RE: Multiple Cell Phones
jsolar
RE: Multiple Cell Phones
These other systems use a cellular data modem module built by companies such as Advantra, Conxtra, or Skybility, and a service provider such as Aeris. A company builds their product around the cellular modem module and contracts with Aeris, who in term has established contracts with all of the cellular providers for data collection and forwarding.
You don't have to "roll your own" One example of a system made for remote fluid level measurement is as follows:
http://wir
RE: Multiple Cell Phones
RE: Multiple Cell Phones
Is SMS the text messaging protocol? So, if I have a remote system, and use one of these cell modem modules where the interface is simply serial, do the text messages just transfer to and from via using the port? For example (im not all up on texting...my kids use it I dont) if I text a phone number 555-5555 and send the message "OPEN VALVE #3" I assume the network sends the text message to the phone number where the cell modem answers..does it just pass the serial text data to the port where my micro can then read and act...plus ack the message? I guess on the ack....is the phone number that sent the message embedded into the message itself..so that the micro could call it back sending a message as well.
RE: Multiple Cell Phones
I hope this hasn't deviated too much from the original subject
RE: Multiple Cell Phones
hrc did you look at that last link "tinyplanet"? It is sort of a tutorial on the subject.
RE: Multiple Cell Phones
When the power grid was knocked off line for a week or more by Hurricane Juan in 2003, they sent around sludge trucks to pump out the pits before they overflowed onto the street. I assume that the pits 'phoned home' using backup batteries.
It seems to be a low power packet radio network. I'm guessing it is low power due to the very nice high gain antennas. If it was (for example) ten watts, then I assume that they could've just used simple whips.
RE: Multiple Cell Phones
RE: Multiple Cell Phones
RE: Multiple Cell Phones
RE: Multiple Cell Phones
Do you know an Ad Hoc Network?. It's an independent mobile network.
RE: Multiple Cell Phones
RE: Multiple Cell Phones
Not sure of the geography of your application, but we've had good luck with the unlicensed broadband radio systems over fairly long distances and rough terrain. Might check www.elprotech.com. These have worked well for us for water and sewage pump station monitoring.
RE: Multiple Cell Phones