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# nRF51822_SimpleChat Extended With Data Measurements & Logger for Power Consumption Monitoring
This repo is derived from the initial SimpleChat Application and it is build for BLE Nano Device, used in peripheral mode.
The aim of this app is to count the flashing red LED of a power consumption meter. 
This Application scan every 10 msec and measures AI port A5 to which a photoresistor is connected. Each 1 second the system save the collected data 
(if there is something to save) into flash with timestamp added. A RTC has been implemented.
Using chat application (available for smart phones) some commands can be send to BLE Nano in order to perform some tasks. Also some real time measurement
are displayed on the phone app.
Other types of commands can be send via serial interface from a PC, especially data extraction from flash.

#Usage/Description:
After flashing or power on, the ble device will start to advertise and also its local time counter starts. While initializing, application 
will search through all flash pages, last data previosly written. From this pages will retrieve the last data and time available. 
A Timer Tick (period set to 1 second) is used for updating RTC and for data measurements. When the application starts the data will not be saved
in flash until a command is given to start (xf2 + enter). When started, it is recommended after connecting to ble device to set the time and date;
After the date and time updated, activate measurement logging (command: xf2 +enter).

Please be aware that from time to time the connection is stopped by the application in order to perform a flash writing procedure. 
This is due to fact that  writing to flash is safe when radio connection is off. When g_MyDataIdx is between 248..251, connection should remain closed.

The Application can use somewhere around 100 flash pages (100K). This means, if data is sampled each second, the pages will start
to overwrite after 251*104 seconds = 7.25 hours. Anyway the data is inserted into logger if there is a measurement different than 0. 
Therefore the time the flash memory can log is bigger than 7.25 hours.

When retrieving the data log via serial, the format is as follows:
-> page starts with: 
2016_ 4_22 H: 7   => year, month, day, and hour
26:51;10;=> minutes: seconds; A5  (no info about digital inputs)
-> following rows up to the next page:
0: 5;12;  => minutes: seconds - time delta (time elapsed since last measurement); A5;

#Hardware Connections
The BLE Nano Device is connected to some peripheral components as follows:
* Light Photo Sensor ( A5 input). This sensor must be placed on the top of the LED that it monitors, and must be completely covered 
    (to avoid other light source disturbances)
[*] Optional: MKUSB 20 Board (for Voltage Supply and for Serial Communication with a PC)

# Supported Commands
From RedBear Chat Application following messages are valid:
* Any message that not start with 'x' is echoed with 'R:' as prefix, and also is send via Serial Interface to PC
* Any message that start with 'x' is interpreted as command:
    * xr*  * = {0-7} => prints some data parameters or data measurements as follows:
        * xr0 ->NH (last number of hits per second) and TNH (total number of hits, from the moment of Power On)
        * xr1 ->maxV,photoVoltage.read(),minV : Highest Voltage measured on AI5, Current Measurement of AI5 and the lowest reading.
                (maximum and minimum are computed at the start of BLE, until the xf2 command is given (start of collecting data).
                These values are used to set the median Voltage used to identify a transition from low to high and vice-versa.                
        * xr2 -> prints the value of g_MyDataIdx (a value now between 0..251) representing the steps until a new page will be written
            in flash with new data; It also print the current flash page that will be written (between 151 and 255)
        * xr3 -> prints the voltage of the RedBear power supply (if it is on battery it will be a lower value than 3.3V). USefull to see how
                discharged the battery is;
        * xr4 -> prints the voltage of the AI5 (current photoresistor drop voltage) and the median voltage used to counter the transition from
                low to high and vice-versa;        
    * xl => toggle led status (LED1, on the bottom side of the BLE Nano)    
    * xtg => returns the current time
    * xti[0-9]{6} => insert time - exp: xti181004 means: 18H10M and 4 seconds
    * xdg => returns the current date
    * xdi[0-9]{6} => insert date - exp: xti160424 means: 2016 Y, 04 Month, 24 Day
    * xf1 => prints the value of g_MyDataIdx (a value now between 0..251) representing the steps until a new page will be written
            in flash with new data; It also print the current flash page that will be written (between 151 and 255)
    * xf2 => activate measurements logging;
    * xf3 => deactivate measurements logging and save the last data in the flash region;       
    
    * xim => eg ximXY =>introduce a value for median Voltage. This value will be computed as median = XY/10; 
    
From PC serial interface (with MKUSB 20 Board), following commands apply:
    * xf[0-9] => request printing on serial of a specific flash page ( 0 - current page; 1 - previous page, etc)
    * xd => request dump of all recorded logs (starting with current page)
    * xg => prints the value of g_MyDataIdx (a value now between 0..251) representing the steps until a new page will be written
            in flash with new data;       
    * xca => open Radio Advertising  (should be used when the Advertising is Off)
    * xcc => Close Radio connection (should be used when Connection is in Connected state)
    * xcs => Stop Radio Advertising (should be used when Advertising is active)

Other Commands:
    -

# References
The mbed BLE API is meant to be used in projects on developer.mbed.org. Please see examples and sample project files there. 
A good starting point are these pages:
* [mbed BLE Homepage](http://developer.mbed.org/teams/Bluetooth-Low-Energy/) for all things BLE
* [mbed BLE Getting Started Guide](http://developer.mbed.org/forum/team-63-Bluetooth-Low-Energy-community/topic/5262/) a wonderful primer on using BLE with mbed
* [mbed BLE API page](http://developer.mbed.org/teams/Bluetooth-Low-Energy/code/BLE_API/docs/tip/) for the API in generated by doxygen

For this Application:
* [redBEar Ble Nano] (http://redbearlab.com/blenano/)
* [Project Blog - to be updated](http://tanasaro10.blogspot.ro/)