Connecting multiple Bluetooth devices for scouting
 

We hope to use six 2013 Nexus 7 Android tablets for scouting this year. Is there a way to get them all to connect via Bluetooth to a single computer (which would be the server?) Ideally we hope to use a Raspberry Pi as a server but if we needed something else we could do so.

Our fallback is to use hardwired ethernet to each tablet but that's more clunky logistically. There's also a problem with Android 4.3 on these tablets not having the right drivers for USB ethernet so some hacking will be involved.

Re: Connecting multiple Bluetooth devices for scouting
 

Team 701 is making the transition to Android Tablets (off of Nintendo DS Systems, ask me about that if you are interested) this year for scouting as well. As head Scout Programmer, I've found the easiest way to connect 6 tablets to a computer wirelessly is to initiate an Ad Hoc server from the computer, or use Google's Chromecast to create a local device to device connection. Then, connect each device to the network, the computer to the network, and run your server. It worked for us using Nintendo DS's and a small wireless router (no actual internet connection involved), and were were able to send data from the Nintendo DS straight to the computer at the end of each match.

If you are interested in learning more about our electronic scouting system, just e-mail me at biosonic42@gmail.com and I can try to help you as best I can. Team 701 is necessarily known outside of the local teams for our database, but we spend a lot of time developing it, and use it to compile performance data for every team at our competitions. The data we use is all recorded by scouters, and none of it has to do with OPR or alliance seeding. It is all about how the individual robot performed on the field, and it helps us tremendously with Alliance Selection and Elim strategies.

Thanks, and I hope I answered your question,

Joseph Lewis

Team 1678 is trying something similar with Bluetooth this year.

Last year, we used two methods of communication. The first was Ethernet (via USB adapters) to a switch and cellular modem. We also implemented charging so there were two cables attaching to each tablet. That system was very clunky, unreliable and just generally awful. Next, we switched to a Raspberry Pi hub (connected to cellular modem) with communication to tablets via the Android Accessory Protocol. Charging and data used one cable and the system was more robust. It was still more complicated to program than we'd like and had some reliability issues at World Championships.

Now, we've updated our tablets to newer models with Bluetooth and aim to go all wireless. Two tablets (out of 8 total) are cellular models so they will function as hub devices for the others to connect to. Our server is actually a PHP application on our team's VPS (virtual private server). That allows our drive team and coaches to have access to the latest scouting data at all times, something we've very useful during competition.

We are just beginning work on Bluetooth development so we haven't yet discovered all the ins and outs but let me know if you have any questions about our system.

Also, one thing to watch out for with Bluetooth is the connected device limit. From what I've read, connecting 6 devices to one device may not function reliably.

Re: Connecting multiple Bluetooth devices for scouting
 

T4:
Not sure how this works with all of the previously mentioned threads on stuff like this.
I should probably ask the question, but does Bluetooth use these, and thereby, is Bluetooth illegal?

Re: Connecting multiple Bluetooth devices for scouting
 

This has been discussed in other threads. A quick summery:
Bluetooth follows the 802.15.1 protocol, so would be legal under the rule you quoted. However, some people have said that they were forced to turn their Bluetooth off anyway.

Re: Connecting multiple Bluetooth devices for scouting
 

Just bring ye ol' trusty notepad in case of an emergency!

Re: Connecting multiple Bluetooth devices for scouting
 

What we do is use a local database and then sync them up later. We can usually get the data pretty quickly, to get around the network rule we will sometimes have someone run out into the parking lot with a hotspot and the tablets and sync it up outside of the no wifi area.

On another note, why 6 tablets this year? We used 6 last year, but this year we are pretty sure we can do it with 2. Except for the autonomous it should be pretty straight forward shouldn't it? (I want to make sure I am not missing something, our first data collection meeting is probably Saturday).

Re: Connecting multiple Bluetooth devices for scouting
 

For the past few years we've used a collector program that we wrote running on a laptop that searches drives for a specific file, then we plug each of the devices in through USB and the program automatically collects the data for us.

Re: Connecting multiple Bluetooth devices for scouting
 

Thanks for everyone's responses. In previous years we've used 3G connected iPad 1s but those connections have severe problems at some venues and especially and Championships where AT&T 3G was completely saturated. Typically we write these programs as web applications so Javascript and Node.

Our software team working on this doesn't have experience writing native Android applications. It's likely too late to learn this cycle. This year we'd like to continue running our competitive analysis system in a browser being served up by a web server, a local one this year.

notmattlythgoe makes an interesting point about using USB and polling for special files on each tablet from a "server". If we can't come up with a cleaner solution that would be a good fallback. Hopefully we can get our Ethernet adapters to work on 4.3.

I was hoping there was some Bluetooth magic that would allow these tablets to connect to a local network over that pipe. If anyone knows of such a thing, let us know!

Re: Connecting multiple Bluetooth devices for scouting
 

Oh, and to answer hardcopi (why not just use two tablets), we're looking for the best data we can get on each robot. We'll be tracking things like the number of attempted passes, number of completed passes, number of shots attempted and number successful, subjective data, etc. You might get away with it with two scouts but those would be busy scouts!

Re: Connecting multiple Bluetooth devices for scouting
 

Hello fellow scouters,

FIRST Team 1073 made the switch to a tablet system in 2012, using up to six Andrdoid tablets to capture the scouting data for pit and match scouting. We have had the tablets sync to a central laptop over bluetooth, where the scouting data is processed and stored in a database. From there, all sorts of reports can be retrieved, including a weighted scoring list of teams that represent our "pick-list". The central laptop provides a web server to serve the reports over HTTP.

The bluetooth sync works great. We generally sync each tablet one at a time to avoid any contention, and have experienced no issues to date with that method. We also use a 3G tablet to upload the collected data to another copy of the central application that is running up in the Amazon Web Services cloud. We did this so that any team member with a smartphone or internet access can view the scouting data in real time from anywhere.

If anyone wants some additional information on how our system works, send me a private message and I'll be happy to provide as much detail as you need. All of our code is available from GitHub, and that may save you some time should you want to get a head start. In fact, our Android tablet application itself is generated from a spreadsheet that defines the attributes that a team wants to collect/measure. We can easily generate a custom application for you with your scouting "sheet" to give you a taste of what the system can do.

KenSt (aka RoboScout)
Mentor - FIRST Team 1073

Re: Connecting multiple Bluetooth devices for scouting
 

RoboScout,
Interesting that you connect one tablet at a time. Is that an automated process back on the laptop or is that manual?

It sounds like your front-end is a spreadsheet that your save periodically and retrieve to the central laptop. Do I have that right?

Re: Connecting multiple Bluetooth devices for scouting
 

If you'd like I can post our compilation software for your use. It's not the greatest out there and could definitely use some work but it does what it needs to.

Re: Connecting multiple Bluetooth devices for scouting
 

No, sorry to confuse you, the front end is an Android application.

In order to minimize the new development year over year, and to allow the students without a software background to build the application, we wrote a code generator to build the Android application. The code generator takes a spreadsheet file as input, and generates the Java application source files from which the application is built. The code generator supports radio buttons, checkboxes, text fields, a custom scoring matrix for the UI.

Why I mentioned the spreadsheet in my post was that you indicated that your team doesn't have much experience with Android development. Perhaps, we could spin a version of the app for you.

And, yes, there is a 'sync' button on the UI that allows a scouter to sync the collected files on demand. We chose that model early on so that we could make sure that each transfer completed successfully. Now, that we have two seasons under our belt with the application, we may shift over to an auto-sync, but simple and reliable is good, too.

Re: Connecting multiple Bluetooth devices for scouting
 

I had this same idea for generating the Android UI but we have not had a chance to implement it yet. Now with Tableau as a data analysis source the android app is the only part of our software chain that needs rewritten each year. I'd love to get it to the point that the most we'd have to do is add an implementation for a new type of UI widget if the needs arises.

Re: Connecting multiple Bluetooth devices for scouting
 

RoboScout,
Pretty fancy stuff!

I see the development of the scouting application as another important project for the the team to develop, just like building the robot. It's a project full of constraints, pitfalls and opportunities. If we get in a bind, though, we might take you up on your generous offer.

notmattlythgoe,
Thanks for your offer as well. We'll see how far we get on the Ethernet and Bluetooth. If neither pan out, given our skill set, your software might be very handy.

Re: Connecting multiple Bluetooth devices for scouting
 

Acutally I guess we are using 4 scouts. Just two tablets though. Two data collectors and two spotters who will be an extra set of eyes.

I agree though to our team data is every bit of important (well almost) as the robot itself. A great robot can have a few bad match ups depending on your partners. The data can be used to help show what your bot can really do.

I am thinking right now of doing it almost like we did last year just for simplicity sake.

I am curious though what stats everyone is taking. That is kinda the basics of our meeting on Saturday. Getting the data is pretty straight forward, but getting the right data isn't so easy.

I know our data last year by St. Louis was good enough to be able to predict the last day of Archimedes within 2-5 points for each bot. The only ones we missed were due to mechanical malfunctions.

Re: Connecting multiple Bluetooth devices for scouting
 

Absolutely agree with your approach. BTW, we're novices with the Android SDK, too. We used several of the example apps from the SDK as a basis for our implementations. And, this guy's site is always helpful: http://www.vogella.com/tutorials/

Good luck and feel free to check out our GitHub repo for a reference. Send along any questions.

Re: Connecting multiple Bluetooth devices for scouting
 

Our latest path to explore is using PhoneGap to make a Javascript application into a native Android application. There are APIs that allow PhoneGap applications to create and manipulate files on the Android device. We'd then use USB (or maybe Bluetooth) to get those files onto a central computer (probably a Raspberry Pi) similar to what notmattlythgoe is doing. Any advice on pitfalls to this approach would be appreciated.