How to Download Data from Electricity Meters via ESP32 Bluetooth?

Question

Hi all,
I have two electricity meters with a bluetooth module and would like to download data via ESP32.
I am currently communicating with them using the E-test app on my phone, but there is no way to upload data to the server.
Does anyone know how to download data using the ESP32?
Thank you in advance for your help.

.

khoam · Accepted Answer

The description of the protocol is here: Link . I would also suggest that you ask the moderator to move this thread to the automatics section. The issue is multi-domain.

powerT · Answer

Serial Bluetooth Terminal is a smartphone app, a terminal simply (like Serial USB). Add a parser to the ESP32 so it understands what you are sending to it and what you want it to do. It can also send you messages. Here is a link : Link .

khoam · Answer

There is a BluetoothSerial class available in Arduino Core for ESP32 that you can use for such things. Example: Link .

powerT · Answer

A, this is what CI meant. It's best to send data from the device in what formatted form for you.
Pay attention to the marketplaces, the sending device must retain this syntax:

?Sensor, 1, 100! .

Sensor is a name, stored on receipt is in the variable: char[32] messageFromBT
1 is an integer, it is stored upon receipt in the variable: int int1FromBT
100 is an integer, it is stored upon receipt in the variable: int2FromBT

There is no problem to match, float or double. The parser works on a message with 3 parameters
? and ! you can also change it e.g. to < >
then you send from the transmitter like this:
<Sensor, 3, 23 > .

code (ESP32)


#include "BluetoothSerial.h" 
BluetoothSerial SerialBT;  

const byte numChars = 32;    
char receivedChars[numChars];
char tempChars[numChars];      
char messageFromBT[numChars] = {0};
int int1FromBT = 0;                                 
int int2FromBT = 0;                                 
boolean newData = false;                       

void setup()
{
             SerialBT.begin("BT-TOMEK");   
}

void loop()
{
               BlueToothCheck() ;
}

// -------------------------------------------------------------------------------------------------- //
// --- B L U E   T O O T H   C H E C K   I N C O M I N G   M S G                                  --- //
// -------------------------------------------------------------------------------------------------- //
void BlueToothCheck() 
{                                      
    static boolean recvInProgress = false;
    static byte ndx = 0;                               
    char startMarker = '?';                           
    char endMarker   = '!';                           
    char iChar;                                              
                                                                     
    if (SerialBT.available() > 0 && newData == false)
    {                                                                                
        iChar = SerialBT.read();                                      
                                                                                     
        if (recvInProgress == true)                                 
        {                                                                            
            if (iChar != endMarker)                                   
            {                                                                        
                receivedChars[ndx] = iChar;                      
                ndx++;                                                         
                if (ndx >= numChars) ndx = numChars - 1;
            }                                                                          
            else                                                                     
            {                                                                           
                receivedChars[ndx] = '\0';                             
                recvInProgress = false;                                  
                ndx = 0;                                                           
                newData = true;                                             
            }                                                                            
        }                                                                                
        else                                                                          
        if (iChar == startMarker) recvInProgress = true; 
    }                                                                                   
                                                                                       

    if (newData == true)
    {                                 
        strcpy(tempChars, receivedChars);         

        BlueToothParseData();                 
        BlueToothShowParsedData();     
        // BlueToothParseAction();     jakas twoja funkcja by cos zrobic ze sparsowanymi danymi
        newData = false;                          
    }                                                         
}                                                             
// -------------------------------------------------------------------------------------------------- //
// ---   P A R S E R   D A T A   F R O M   B T
// -------------------------------------------------------------------------------------------------- //
//                                                                      
void BlueToothParseData()                            
{                                                                        
    char * strtokIndx;                                        
                                                                          
    strtokIndx = strtok(tempChars,",");             
    strcpy(messageFromBT, strtokIndx);         
                                                                          
    strtokIndx = strtok(NULL, ",");                    
    int1FromBT = atoi(strtokIndx);                  
                                                                          
    strtokIndx = strtok(NULL, ",");                    
    int2FromBT = atoi(strtokIndx);                  
}                                                                                                                               
// -------------------------------------------------------------------------------------------------- //
// --- S H O W   P A R S E D   D A T A   F R O M   B L U E T O O T H    
// -------------------------------------------------------------------------------------------------- //
void BlueToothShowParsedData()    
{                                                           
            Serial.printf("\nShowBT Parsed Data -> Wiadomość    : %s", messageFromBT );             
            Serial.printf("\nShowBT Parsed Data -> Integer nr.1 : %d", int1FromBT );                 
            Serial.printf("\nShowBT Parsed Data -> Integer nr.2 : %d", int2FromBT );               
}

.

globalinfo · Answer

This terminal I tested, but the counter sends chaff which I cannot process.

.

What I want is for the ESP32 to be able to connect to the counter and process the data received, because I don't need all of it.

khoam · Answer

. Do you know the format of this transmitted data?

globalinfo · Answer

This is where the problem is I don't really know how to recognise it.

globalinfo · Answer

. Just how via ESP32 to establish a connection over bluetooth?

powerT · Answer

. ESP with your smartphone ? or ESP with your device ?

globalinfo · Answer

ESP32 with counter. I have run the scanner on the ESP32 the scan result below: . The first two items are counters.

powerT · Answer

and this is no longer ESP but industrial automation. Reprogram your devices to prepare with ESP, not the other way around. How you do this and whether you can do it is a matter of getting to know the specifics of the readers, not ESP.

globalinfo · Answer

. Are you sure I need to reprogram? I found a tutorial where the ESP connects to the bracelet - Link . Once up and running I was able to connect. . The attached picture shows the active bluetooth symbol. .

khoam · Answer

. So in the next step, using the class BluetoothSerial you need to send a command to the counter, according to the protocol description I posted in the previous post, and after receiving the response, extract the necessary data. The BluetoothSerial class is handled analogously to the Serial class and there are quite a few examples on the web. Link . Link .

globalinfo · Answer

. Somehow it doesn't work for me . Preparing works, but at least the voltage and current would be useful. Code: C / C++Log in, to see the code .

globalinfo · Answer

Well, that's a bit better - I'm getting the data from the meter. . My question is whether it is possible for one ESP32 to connect to two meters - I would like to download data from the meter on electricity consumption and production.

Anonymous · Answer

Are these data instantaneous or averaged values ?

If instantaneous then the accuracy of the measurement of the energy consumed/generated will depend on the sampling rate (on the frequency of the readings).

[edit]
Also, something doesn't add up here:

Quote:
.
Downloaded values:
- Voltage : 237.2
- Current : 0.143
- Power : 13.6 .

.

237.2V * 0.143A = 33.9W and the result shows 13.6 (of what?). Maybe these are Wh (energy) and not W (power)?

[Edit 2]
It would even be logical that this meter gives instantaneous voltage and current and energy and not power.

[edit 3]
It is quite easy to check this. Just unplug the consumers and check the result. if the second value (amperage) is zero and the first and second still show values > 0 it means that the third is the amount of energy (Wh) and not power (W).

khoam · Answer

. Yes, but not at the same time.

globalinfo · Answer

. The above figures were with the power supply load from the laptop. Count the following data for yourself - heater load. .

Anonymous · Answer

. So where did the otherwise sizable difference come from?

globalinfo · Answer

. [Active Power] = [Voltage] * [Current] * [Power Support].

Anonymous · Answer

. Well yes - that explains why with the heater the result was correct.

globalinfo · Answer

Tyko how to select the connection when the devices have the same names. .

globalinfo · Answer

I am connecting to two counters at the same time using the program below. I don't quite know how to display the received data from the counters now. . Code: C / C++Log in, to see the code .

How to Download Data from Electricity Meters via ESP32 Bluetooth?

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