Topic Type
Idea

If a Farmer needs to monitor multiple locations, there are a couple of different ways we could tackle this.

  1. Use more than one Fido With more than one Fido, multiple cellphones will be involved and the cellphone numbers could be considered the unique identifiers for the Fidos on the farmer's end.
  2. Multiple sensors on one Fido If the Farmer needs alerts on multiple locations but each of those locations is in close proximity then adding multiple sensors wired to Fido could be possible. With multiple sensors wired to one Fido we may want to include a unique ID for each sensor to distinguish between the sensors. Something like, "txt from 802-555-5555: Sensor 2 detected temperatures above 100".
  3. One Fido connected to multiple wireless sensors If the farmer needs more than one Fido on their property then we can cut their cost down by having them use one Fido that communicates with multiple wireless sensors. This is a big enough change in the hardware/code that we may have to consider it to be a whole other tool.
Forums
Greenhouse Monitoring with Text Message Alerts
Forum comment

Thanks for the summary RJ - this is all right on! 1 is pretty straightforward and requires no more development based on our current objectives. 2 is definitely an option, would require very little extra development but requires a lot of wire even if you want to hook up two neigboring greenhouses to one Fido since you basically have to find a relatively central location and then run three wires to each sensor - luckily these are digital sensors so the resistance in the wire isn't an issue as long the signal still makes it through. 3 is also technically viable but as you pointed out, is quite a big change on the development side. How do we tackle the "wireless" part of the sensors? Xbees? WiFi? something else? The money spent making these things wireless would probably be at least as much as simply building seperate Fidos. This is a type of architecture I am foreseeing for the wireless node system that relays data via internet, however!
Forum comment

Just a concept at this point, but I'd like to try out something like this as an RF transmitter / receiver: http://www.sparkfun.com/products/10535 http://www.sparkfun.com/products/10533 Perhaps be able to make sub $20 sensor / transmitters that would send temperature information back to a base unit with the cell phone connection. I am setting up a new farming area where I would have 8 to 10 mini tunnels. Some might be covered in plastic, some might not. It would be critical in the spring to know how hot it is in each of them.
Forum comment

Would you pair each one of these with an Arduino? If so, that seems like a hassle and you might be better off using [Xbee chips](http://www.sparkfun.com/products/10414) since they would be able to take your readings and send them without an Arduino and you would be saving some money and development time. It might be a fun project to buy the RF transmitter/receive modules and pair them with AVR chips yourself (ie: buying the chip and not the Arduino) and you might finagle something cheaper than an Xbee chip but otherwise I'd recommend Xbee with an analog sensor.
Forum comment

You'll need something to convert the sensor signal to serial data so it could be sent over the XBee's modem. Unless you're just sending 1 bit of info, in which case you can use the DTR pin on the XBee. This would probably work for preset alarm info.