Determine what bluetooth signals vehicles give off and how they can be read while in the foreground and background

[shankari]

• Find a sample bluetooth app that displays readings on the screen and also logs them
• Install it on the test phones (compiling if necessary) and walk around and see which signals are present while running in both in the foreground and the background
  • I expect that iOS will show bluetooth signatures in the foreground but not in the background
  • I also expect that if we can put in the bluetooth signal that we find in the foreground into the scan message, it will work in the background as well (this we may have to write/modify code for)
• Once we have preliminary results, we should write up a test plan and collect rigorous data for a paper later
• Then we should decide how to proceed

[the-bay-kay]

Initial Findings

I've been diving head first into Bluetooth research; here's some notes and thoughts on what I've found so far!

A Note on Key Fobs

• Smart key fobs (the kind you can leave in your pocket) seem to operate at around 300Mhz - 8000 Mhz, towards the lower end of the Industrial, Scientific, & Medical (ISM) radio band (visualization here!), which is a significantly lower than Bluetooth's operating frequency of around 2.4 Ghz (link), so I don't think we could use them as a beacon.
  • Once we get access to the GACA, I'll do a deep dive into what types of Bluetooth we'll have access to; my guess is, the on-board stereo will be the most readily available.

Bluetooth v.s. Bluetooth Low-Energy (BLE)

• If anyone else is interested, I found this article to be really helpful when it comes to understanding the broad-stroke differences between Bluetooth and BLE.
• In my research, I stumbled across this Cordova BLE plugin that seems like exactly what we'd need! If standard Bluetooth doesn't pan out, this seems like a great plug-and-play backup. Honestly, pretty excited to find a well-maintained plugin that would handle this for us.
• I do worry somewhat about the reliability of standard Bluetooth. Since it exists in a binary state (whereas BLE can "hibernate"), I think there's a non-zero chance that a "stereo beacon" may not be transmitting for the entire duration of a trip; since we couldn't "wake" the stereo from the phone, we'd need the user to constantly have Bluetooth enabled.
  • Why I'm concerned: some stereos, like the ones I've worked with, have different media modes -- in order to access Bluetooth, you have to manually change the stereo to that setting. My hypothesis is, the stereo is not broadcasting unless it's set to Bluetooth. A consequence of this would be that, if I wanted to listen to the radio for my commute, my trip wouldn't register. Once I've got a Bluetooth meter app installed (see below!), I'll go out to my car and do some tests.
  • There's also a conversation to be had about battery consumption, but we'd have to test the difference in battery drain between Bluetooth receiver protocols -- there's for sure a difference when transmitting, but I can't find any conclusive evidence on the receiver behavior.

Sample Bluetooth Meter Apps

• From what I can tell, there's pretty slim pickings for apps that are: (a) Open Source, (b) Cross-Platform, and (c) Actively maintained.
  • I personally thing (a) and (c) are the highest priority -- It'd be nice to see a Cordova-esq (Flutter, React-Native, etc.) implementation of standard Bluetooth, but I think having up-to-date code examples is more important.
  • There seem to be a ton of desktop Bluetooth scanners, if we just want to see protocols and device availability. I won't include them here, but there are plenty of options I've jotted down! Some of these software suites are used for pen testing, so we'd want to tread carefully...
• Below is a quick table containing the Mobile App options I've found so far!

App Name	Link	Last Updated	iOS	Android	Bluetooth	BLE	Open Source
OpenBLE	link	11 Years Ago	✓			✓	✓
Bluetooth Scanner	link	7 Years Ago		✓	✓	✓	✓
BleCORE†	link	Today!		✓	✓	✓	✓
BlueSniff	link	2 Years Ago	✓		?	✓
Bluetooth Finder, Scanner Pair	link	This Year!		✓	✓	?
Simple Bluetooth Scanner	link	Two Years Ago	✓		✓	?	✓

†The docs for BleCORE are in Mandarin -- from what I can gather, their demo app does what we want to test (just in Kotlin). If we want to look into this further, I've got a friend that could help me read through the docs!

Final Notes

I'll keep adding to the table above as I find more example apps -- if anyone's familiar with some, please let me know! As the table shows, there doesn't seem to be a "one-size fits all" example project that we could use as a code reference. I may start with a desktop BLE scanner on my personal computer, just to test my stereo-broadcast hypothesis -- once I've got more data, I'll make another post on this thread!

[shankari]

Couple of high-level thoughts:

In my research, I stumbled across this Cordova BLE plugin that seems like exactly what we'd need! If standard Bluetooth doesn't pan out, this seems like a great plug-and-play backup. Honestly, pretty excited to find a well-maintained plugin that would handle this for us.

Yes, cordova has plugins for lots of things - some cordova app developers have never written native code - only javascript, and will not implement functionality if they have to drop down to native. We can definitely reuse code from it, but I don't think we will want to use it as a plugin directly because plugins are intended to be called from javascript, and we want to call the bluetooth from the FSM that is implemented in native code

[the-bay-kay]

Making a Bluetooth Test Scanner

Just putting some initial thoughts on the project here!

The goal is to make a very simiple app that allows us to see a list of all currently broadcasting Bluetooth devices within capture distance. Since our research revealed that there isn't a "one-size fits all" app, the plan is to make a simple one ourselves. Admittedly, we could use a selection of the apps detailed above, but I think this will be a helpful learning exercise!

I'm thinking we make this app in React + Cordova, since it's what we're already using.

Task Brainstorm

• Set up repository for the project, link here / elsewhere
• Figure out how to prompt the user for Bluetooth Permissions (I believe this is a req)
• I believe we can use this plugin for our Bluetooth API. We'll obviously need to write our own native code later, but this will suffice for the test app
• For the code, some requirements may be:
  • A react component to store device data (e.g., OID, signal strength, type (BLE / Classic) ).
    • Each component could render as "Device Name + Type", and use OID if no name is available
  • A JS method that performs a scan, and returns a list of objects with the device data listed above
  • Find a method to "refresh" the list; either via a manual refresh,
  • A page that contains a scrolling list of the Device Components (propagated via the "scan()" method)
• Write up / finish documentation on building to hardware
• Write a brief tutorial on how to use the app and record results
• Send off to the team for testing!

What's Next

Louis and I are meeting tomorrow to discuss these rough plans -- we'll find a way to divvy up the task, and update this thread with our progress!

[shankari]

@the-bay-kay @louisg1337 I wanted to suggest that instead of building a new app and setting up the toolchain all over again, you can just change the existing app. My suggestion would be:

• add the bluetooth plugin to e-mission-phone by simply changing the package.json
• create a new screen to display bluetooth values and log them to the database
• make the screen conditional on a config flag
• set the config flag to true on the GSA config and only the GSA config

That way, when people install the "GSA configured" app on their test phones, they can also test out the bluetooth without having to recompile.

Thoughts?

[the-bay-kay]

@the-bay-kay @louisg1337 I wanted to suggest that instead of building a new app and setting up the toolchain all over again, you can just change the existing app...

I think this is a great idea!! I spent some time chatting with Louis yesterday about designing an app from the ground up, but having the scanner hidden under the dev options would be far easier to implement. Plus, it'd make the distribution of the scanner way easier -- we'll pivot to making it an addition!

[the-bay-kay]

Update on Plugin Search

When working on PR 1128, we've looked into a few other Bluetooth plugins and resources. Below is an updated table, along with some additional notes / resources.

Most notably, Louis found a fork of the Bluetooth Serial Plugin that theoretically supports iOS Bluetooth scanning. There are, however, a few caveats:

iOS applications need additional configuration to allow Bluetooth to run in the background.

According to these docs, it appears that iOS devices cannot scan for unrecognized Bluetooth devices in the background. I believe this means that we will be able to scan in the foreground, but I need to do further reading on the iOS Bluetooth docs (link) to determine how viable this approach is.

As of writing, we are using the original plugin (link) in PR 1128 . I'll update this thread further when we test the fork that enables iOS bluetooth classic scanning!

Bluetooth Scanning Plugins

App Name	Link	Last Updated	iOS	Android	Bluetooth	BLE	Open Source
OpenBLE	link	11 Years Ago	✓			✓	✓
Bluetooth Scanner	link	7 Years Ago		✓	✓	✓	✓
BleCORE	link	Today!		✓	✓	✓	✓
BlueSniff	link	2 Years Ago	✓		?	✓
Bluetooth Finder, Scanner Pair	link	This Year!		✓	✓	?
Simple Bluetooth Scanner	link	2 Years Ago	✓		✓	?	✓
Bluetooth Serial	link	6 Years Ago	✓*	✓	✓	✓*	✓
Bluetooth Serial Fork	link	3 Months Ago	✓*	✓	✓	✓	✓

[louisg1337]

BLE Beacon Candidates

Below is a list of different BLE beacons that we can use for this project.

• Accent Systems iBKS 105
  These beacons are @the-bay-kay certified as she saw these beacons being used in a project by the DOT in Buffalo. They check all the regulatory boxes we must meet for BLE beacons, and are relatively cheap <$20 per unit. We have ordered 5 already and this so far is our best choice.

• Zebra Technology MB1000 Beacon
  This company was recommended by a colleague in NREL as they are based and manufacture in the U.S. They have unfortunately not gotten back to me after ~2 weeks, so although promising, may not be a viable choice.

• Estimote Beacons
  The intended use case for these beacons is for spatial awareness, so they may be a bit too overkill for our application. They are advertised as UWB beacons, but have BLE compatibility as well. The beacons come with a custom SDK that seems like it makes the usage of the beacons super easy (its behind a paywall though so can't confirm). They also have these cool BLE stickers, but they only have a battery life of 6-12 months and the batteries are not replaceable (super sad). I am currently in contact with them though to see if their former product is viable for our needs.

  • UPDATE: I spoke with the CEO of Estimote and got some more information. They have a beacon designed specifically for cars that 1) look cool and 2) are more sleek than other beacons. The beacons themselves are both BLE and UWB enabled, and even though we only need BLE, having that UWB capability is pretty cool. It's important to note though that UWB is only available on Android 14+ devices and iPhone 11+. They also have their own SDK that we can use to potentially make the development process easier. In terms of logistics, the beacons are manufactured in NATO countries in Europe and are around $20-$30 depending on the quantity we are buying.

• Willot IoT Pixels
  These BLE beacons are super cool, but also seem a bit overkill. They are sticker sized beacons that harvest nearby RF waves for energy, so they don't need batteries. There are a bunch of integrated sensors within these beacons that can detect location, humidity, and temperature. The only issue with these is that they also sell their own cloud management system for these beacons, which may be the only way to communicate with them. Since we only need to sense the BLE signal, this may not be an issue for us. I am also in contact with them right now to discuss if their product can work for us.

  • UPDATE: These beacons look like they are not going to work out unfortunately. The RF harvesting technology isn't as magical as we thought, as you need a bridge that emits RF waves to power the pixel. Needing a big energizer defeats the purpose of why we liked the pixel in the first place, being that it was a small sticker. Willot also said they were looking to roll out their product to customers with a 1M+ unit case, which isn't feasible for our project.

I'll add more to the list once I get more information from each company, and if I find any other good candidates.

[shankari]

Current decision:

1. we will check in the changes so far and merge them since they are isolated to the dev zone
2. we will pivot to BLE and write a very similar scanner
3. we will work on the FSM
4. return to Bluetooth classic if we have time

[shankari]

For the FSM changes, I think we can handle it in two approaches, and we may even need both to be safe.

1. Keep the existing geofence exit but when we get the EXITED_GEOFENCE event, check fleet deployment or not. If fleet, scan to see if a known bluetooth is nearby and only start tracking in that case. TBD: record the bluetooth scan that we saw so we can map the trip to the vehicle during post-processing
2. Register for iBeacon enter/exit and if we get an enter with a known bluetooth, then:
   a. start tracking location
   b. check to see that there has been sufficient duration or distance or something from previous trip end and then start tracking location

Implement (2a), check power and accuracy, decide whether we need the complexity of (2b)

Both of the above are for trip start which is the crucial part because we should not be tracking non-fleet trips, that is our promise. But we should document how to handle trip end for the record.

1. Keep the existing dwell time trip end algorithm
2. When we exit the iBeacon range, end the trip

[the-bay-kay]

Plugin updates!

@louisg1337 did some digging on our preexisting list of plugins, and found that the cordova-plugin-ble-central seems to be (i) the most popular BLE plugin, and (ii) the most frequently forked plugin. Within this plugin, however, they have a note:

This plugin isn't intended for scanning beacons. Try cordova-plugin-ibeacon for iBeacons.

Following their suggestions, we're looking to add this plugin in our second iteration of the developer Bluetooth scanner!