after doing a few small and easy projects with Arduino I now want to take on a new challenge. I need to build an electronic judging system for a race game. I need to collect 8 timings on 2 lanes and distribute them to multiple HID's. I want to use at least 2 tablets with Android as HID's. This is mainly to read the data but it should also be possible to stop and start the timing system. It should also be possible to collect and store the data on a kind of server to acces is later with a computer program for further analysis.
I currently have a WiFly module and an Arduino Uno board, but I'm not sure if this can do the job. What protocol do you guys recommend? The challenge is that multiple (at least 2) tablets should collect data with an update rate of around 500ms. And the data need to be stored in a data base. Do I need a PcDuino or Raspberry to handle the distribution of the data?
What hardware and protocols (TCP, UDP, WebServer, ...) do you think I should use?
This is mainly to read the data but it should also be possible to stop and start the timing system.
In your context, "mainly" is an extraneous word - you have full duplex requirements... That is, downstream to the tablet and upstream to Arduino.
t should also be possible to collect and store the data on a kind of server to acces is later with a computer program for further analysis.
So, are you specifying "server" because you want one, because you think one will be required for web services, or because there is an inconvenience in using SD? Logically, you should be able to just log the HTTP traffic, I would think.
multiple (at least 2) tablets should collect data with an update rate of around 500ms. And the data need to be stored in a data base.
Projects should be based on known requirements, architecture should deal with infrastructure sizing over time. What is really needed? Is this a one-off or commercial (realized or potential) venture? It does make a difference.
When you say "database" is the need real-time query or post-processing statistics?
Initial take: updating 2 or more tablets at 500mS for multiple dataset(s) can be done with web services, but adding in a realtime SQL component on the save server will impact latency on a whimpy machine. If however, a log stream if activity were appended post game, then database activity is separate from the tablet display (in a temporal sense.). And we have not even considered network (local subnet) latency.
My recommendation is IF this is any kind of a commercial product, get a network engineer and a webmaster on your team immediately. There are too many gaps in your want list to make recommendations comfortably. IF this is a hobby system, I am guessing that with careful choice of network hardware and some tight coding on the webserver and the Ardroid tablets that you could meet your goal.