First of all, I am definitely a beginner here. I have minimal hardware and software knowledge and trying to build something with a developer friend. I bought my first Arduino a year ago and since then I am trying to build the same thing from time to time..
My goal here is to confirm my workflow, parts I use and get advice.
My project goal is to reproduce the well-known Facebook RFID Like Thingy. We have developed the software, built up the hardware and everything is working almost fine. I like to be sure if this is the best way in my situation or if this workflow is stable enough.
to sum it up
We have Arduino Uno + WiFly Shield from Sparkfun + Innovations ID-20 RFID Reader + a Led running. Then written two softwares named as Terminal and Nodes. Terminal software runs on a pc with a rfid reader and a Processing application which reads the tag then pushes it to a browser to load Facebook login to pair a users account with that specific rfid tag. The other software compiled into Arduino Uno, which connects to wifi and the reader stays ready to read a tag. When a tag gets in to the range of reader, Arduino reads the tag and pushes it to server to handle the server-side processes.
So we like this protoype to be wireless and mobile as possible. And we need it to run as perfect as possible in a 1.000 square meter hall room with enough strength/signal. (I say wireless because we really don't want to lay out cables allover 1.000 sq/mt)
There is this fact of battery which is drained by WiFly, what is the best way to let Arduino stay alive long enough like 20 hours a day? Datasheet says WiFly features "Ultra-low power - 4uA sleep, 40mA Rx, 210mA Tx (max)" (I will leave it on whole day tomorrow with a 9V battery and see how long it will stay alive. While developing it drained some batteries but I didn't pay attention to power, it wasn't our priority at that time..)
I have concerns about the range of the WiFly Shield because of the area factor. I am thinking of creating a laptop / hotspot in the field then connect all the Nodes to this hot spot. Then expand the router range with a couple of access points. There is also "2.4GHz Antenna" for WiFly which I received couple of days ago, I will try to test this on the field too (tomorrow probably.)
I guess this would be all, my biggest question is if this WiFly will have issues to connect to WiFi in the field in strength and signal wise - Of course it depends on the field but there won't be any concrete walls or something instead a lot of cell phones. / or even may be external antenna will be unnecessary?
And battery issue.. I don't know how to calculate how much energy it needs to run 20 hours a days for 10 days or what kind of battery and connection I need. If this gets too expensive and complicated I always have the option use a wall adapter.
Also I was thinking of having a 1" oled screen to each node so we can use it as a serial monitor? is it feasible?
Thank you very much for spending your time and getting interested with me.