Android Question Bosch Distance Laser GLM Serie

Wolli013 · Mar 20, 2024

Does anyone here use the Bosch GLM50C or similar?
I would like to make a small app where only the measurement data is transmitted and displayed via BLE.
Does anyone have something like this running?
I have only found the Python code so far.

BOSCH-GLM-rangefinder/glm100c.py at master · philipptrenz/BOSCH-GLM-rangefinder

Python script to remote control a BOSCH GLM 100C rangefinder via its Bluetooth serial interface - philipptrenz/BOSCH-GLM-rangefinder

github.com

walterf25 · Mar 20, 2024

Wolli013 said:
Does anyone here use the Bosch GLM50C or similar?
I would like to make a small app where only the measurement data is transmitted and displayed via BLE.
Does anyone have something like this running?
I have only found the Python code so far.

BOSCH-GLM-rangefinder/glm100c.py at master · philipptrenz/BOSCH-GLM-rangefinder

Python script to remote control a BOSCH GLM 100C rangefinder via its Bluetooth serial interface - philipptrenz/BOSCH-GLM-rangefinder

github.com

From what I understand this device has bluetooth connection, have you tried connecting to it via BLE, you should be able to implement the same code from the python script in B4A.

Wolli013 · Mar 21, 2024

Yes, I have. I use this example program.
As soon as a connection is established, the connection is terminated.

[B4X] BLE 2 - Bluetooth Low Energy

This library replaces the previous BLE library. It is simpler to use and it is more powerful. Its API is based on B4i iBLE library which makes it easy to reuse B4i code. See the iBLE tutorial: https://www.b4x.com/android/forum/threads/ble-bluetooth-low-energy-library.46099/#content Tips &...

www.b4x.com

walterf25 · Mar 21, 2024

Wolli013 said:
Yes, I have. I use this example program.
As soon as a connection is established, the connection is terminated.

[B4X] BLE 2 - Bluetooth Low Energy

This library replaces the previous BLE library. It is simpler to use and it is more powerful. Its API is based on B4i iBLE library which makes it easy to reuse B4i code. See the iBLE tutorial: https://www.b4x.com/android/forum/threads/ble-bluetooth-low-energy-library.46099/#content Tips &...

www.b4x.com

Try the Bluetooth classic library instead, not the BLE.

Wolli013 · Mar 21, 2024

Do you have a link to it?

emexes · Mar 21, 2024

walterf25 said:
Try the Bluetooth classic library instead, not the BLE.

Or try a serial terminal emulation program, see if you can at least connect to the device without being disconnected.

If that is successful, then use Bluetooth (Classic) rather than Bluetooth (Low Energy) - they are different and not compatible, other than coexisting - and every few seconds alternate beween sending these two four-byte commands:

'backlight_on': b'\xC0\x47\x00\x20',
'backlight_off': b'\xC0\x48\x00\x62'

or in B4Xese:

Dim BacklightOn() As Byte = Array As Byte(0xC0, 0x47, 0x00, 0x20)
Dim BacklightOff() As Byte = Array As Byte(0xC0, 0x48, 0x00, 0x62)

Wolli013 · Mar 21, 2024

Where can I find Bluetooth classic examples?
nrf Connect app works

emexes · Mar 21, 2024

https://www.b4x.com/android/help/serial.html

also search for: obd elm bluetooth = a common use for Bluetooth classic serial

emexes · Mar 21, 2024

The definitive example seems to be this:

Android Bluetooth / BluetoothAdmin Tutorial

Better implementation based on B4XPages: https://www.b4x.com/android/forum/threads/b4xpages-bluetooth-chat-example.119014/#content Tutorial was rewritten in April 2018. We will create a chat example between two Android devices. All the non-UI code is implemented in a class named...

www.b4x.com

but your sending routine would be sending Byte Arrays rather than Strings:

B4X:

'Public Sub SendMessage (msg As String)
'    AStream.Write(msg.GetBytes("utf8"))
'End Sub

Public Sub SendCommand (cmd() As Byte)
    AStream.Write(cmd)
End Sub

Dim BacklightOn()  As Byte = Array As Byte(0xC0, 0x47, 0x00, 0x20)
Dim BacklightOff() As Byte = Array As Byte(0xC0, 0x48, 0x00, 0x62)

Do While True
    SendCommand(BacklightOn)
    Sleep(2000)
    SendCommand(BacklightOff)
    Sleep(2000)
Loop

Wolli013 · Mar 21, 2024

Where is this code supposed to go?
The connection is now maintained.

Dim BacklightOn() As Byte = Array As Byte(0xC0, 0x47, 0x00, 0x20)
Dim BacklightOff() As Byte = Array As Byte(0xC0, 0x48, 0x00, 0x62)

Do While True
SendCommand(BacklightOn)
Sleep(2000)
SendCommand(BacklightOff)
Sleep(2000)
Loop

Wolli013 · Mar 21, 2024

How do you get the measurement data from the distance laser?

DonManfred · Mar 21, 2024

Wolli013 said:
Do you have a link to it?

Maybe this one?

[B4XPages] Bluetooth Chat Example

Updated implementation, based on B4XPages of https://www.b4x.com/android/forum/threads/android-bluetooth-bluetoothadmin-tutorial.14768/#content. The code is much simpler compared to the previous example. Note that you can call Serial.Listen without making the device discoverable. This is useful...

www.b4x.com

Wolli013 · Mar 21, 2024

Thanks DonManfred, the connection is established.
The only question is, how do I get the measurement data?
Bluetooth is not something I have much experience with.

DonManfred · Mar 21, 2024

Wolli013 said:
The only question is, how do I get the measurement data?

Does the Device not come with a manual?
Is there no information about the Bluetooth-Data inside the documentation?

Wolli013 · Mar 21, 2024

Yes, but not how to get the measurement data.
That's why I posted a Github script above on how to do it in Python but not with B4A

DonManfred · Mar 21, 2024

Wolli013 said:
but not how to get the measurement data

have you tried to log what you get in the asyncstream newdata event after you started a Distancecalculation?

B4X:

Private Sub AStream_NewData (Buffer() As Byte)
' LOG the Buffer-Data to get inspired
End Sub

Wolli013 · Mar 21, 2024

Nothing is displayed

B4X:

Private Sub AStream_NewData (Buffer() As Byte)
    ChatPage1.NewMessage(BytesToString(Buffer, 0, Buffer.Length, "UTF8"))
    
    Log("AStream_NewData = "&BytesToString(Buffer, 0, Buffer.Length, "UTF8"))
End Sub

emexes · Mar 21, 2024

Wolli013 said:
how do I get the measurement data?

Walk before run.

Can you turn backlight off and on?

Sample code can go pretty much anywhere that runs after connection is established.

Or add two buttons to turn backlight on and off, and put the relevant code in the button handlers.

emexes · Mar 21, 2024

Wolli013 said:
how do I get the measurement data?

The clues are in:

Python:

'measure':          b'\xC0\x40\x00\xEE',

Python:

def measure(self):
    self.socket.send(self.cmds['measure'])
    data = self.socket.recv(1024)
    #print('received:', data)

    if self.status[data[0]] is 'ok':
        try:
            # distance to object from top of device
            distance = int(struct.unpack("<L", data[2:6])[0])*0.05
            #print(distance, 'mm')

but you'd be logging the data bytes like:

B4X:

Sub AStreams1_NewData(Buffer() As Byte)
    Dim bc As ByteConverter
    Log(bc.HexFromBytes(Buffer))
End Sub

B4A - ByteConverter

emexes · Mar 21, 2024

Wolli013 said:
BytesToString(Buffer, 0, Buffer.Length, "UTF8")

Nice try but no cigar. UTF decoding doesn't like random high-bit bytes.

Use:

B4A - ByteConverter

so that we can see the actual value of the bytes.

Second thing is that the meter probably doesn't send any bytes until you send it the four-byte 'measure' command.

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