Here I am is a simple beacon app using Bluetooth communication.
https://www.yamareco.com/modules/yamanote/detail.php?nid=3217
https://www.yamareco.com/modules/yamanote/detail.php?nid=3209

1. Main features
・Here I am Sends the user's ID (identification name) via Bluetooth communication.
・By simply displaying the signal strength of nearby users, you can roughly grasp the distance to other users from the strength of the received signal.

2. Settings
・Bluetooth: ON
・Location information: ON
・Airplane mode: OFF
・App permissions
Permission settings for [location information] and [Bluetooth communication] are required.
"Here I am" does not acquire or use location information, but it is necessary for using Bluetooth communication.

3. App description
1) Start the application ⇒ Enter the user ID (identification name)
"Here I am" prompts for the user's ID (distinguished name) on the startup screen. Up to 13 single-byte alphanumeric characters (4 characters for Japanese input) are valid. The entered ID (identification name) will be sent to and displayed on the smartphones of nearby users of "Here I am", so consideration must be given to the entered ID (identification name).

2) Confirmation of ID (identification name) input
When the ID (identification name) input is confirmed, the ID is displayed in the center, and the system status display is
[OFF].

3) Transmission of beacon signals
When the [BEACON] button is touched in the [OFF] state, the user's ID (identification name) is transmitted by a beacon signal. Touch the [ STOP ] button to stop transmission and return to the [ OFF ] state.

4) Receiving beacon signals
When the SEARCH button is touched in the [OFF] state, the beacon signal levels of nearby "Here I am" users are displayed. The longer the bar on the display, the higher the reception level and the closer the originating location. If you lose sight of the signal for 10 seconds, it will be displayed as Lost. It does not display Bluetooth signals other than "Here I am".

5) Exit the app
In order to properly stop Bluetooth communication when exiting the app, please touch the [Exit] button that is displayed in the startup state and the STOP state to end the application.

4. Target system
"Here I am" targets systems that have an OS version of Android 5.0 or later and that support Bluetooth Low Energy as a terminal specification.

5. Collection and sharing of data
"Here I am" deals with user identity and received signal strength.
Those data are only kept in memory while the app is running, but they are not stored in the smartphone's internal storage, transferred to a server, another app, or a third party, and are not shared, and are used for other purposes. I have not.

6. Other　
- No in-app ads or internet connection.
・Beacon signals are continuously transmitted even when other apps are running, but if other apps use Bluetooth, they may not work properly.
・Please use "Here I am" at your own discretion and responsibility.

7. Release history
・Rel 1.10 March 20, 2023
　　Expanded lower target OS to Android 5.0.
・Rel 1.01 March 19, 2023
・Rel 1.00 March 18, 2023
　　Add permission confirmation and authority acquisition process.
　　Added Bluetooth enable confirmation and enable processing when disabled.
　　Added processing to confirm the validity of location information.
・Rel 0.90 March 4, 2023
　Added filter specifications as a countermeasure against variations in received power display.
A filter ON/OFF switch has also been added so that users can choose to use it.
・Rel 0.84 February 22, 2023
　Added maximum value memory display and reset function for beacon signals.
・Rel 0.83 February 12, 2023
　Speed up Bluetooth SCAN mode.
　　Changed the filter specifications for the received power display.
Fixed a bug that caused the app to stop during Beacon Signal Search.
・Rel 0.80 February 11, 2023
　　Changed the specification to display the amount of change in the received power of the device in color.
　　The display update cycle has been changed from 1 second to 500 ms.
・Rel 0.71 February 4, 2023
　　Bug fix for ID duplication display when restarting
・Rel 0.70 February 3, 2023
　　Add foreground processing (notification) to support interruptions in the background
　　Addition of Notification Icon for foreground processing notifications
　　Limited to Android 8.0 (API level 26) or higher
　　Added an end button for proper control of Bluetooth communication
・Rel 0.63 2022/4/29 icon update
・Rel 0.62 2022/4/3 Google Play release