How do I create/where do I buy a gateway that takes data from specific devices?

Question

Welcome

I am looking for a gateway that I can create or buy and eventually program to collect data from specific devices and send to me to the cloud.

The case is that I have devices that send data over Bluetooth every so often and some of them transmit in real time (every few seconds).

Probably the best solution would be Rasberry or Zigbee but maybe there are other solutions?
How many devices can be connected to such a BT module at the same time? All at the same time.

TvWidget · Accepted Answer

As I have already written the notification frame can contain different information. E.g. beacons send a frame containing the UUID There is no obligation to identify devices by MAC address. The application can use the data in any way it wishes.

TvWidget · Answer

Maybe specify what exactly it means that "devices send data over Bluetooth every so often".
If this is happening every few seconds then this could indicate BLE broadcast frames or BLE connection mode.
Perhaps 'iNode LAN', 'iNode MCU LAN' or 'iNode MCU USB' would be suitable.
If you want to make such a gateway in-house then in my opinion a better solution than RPi would be some board with ESP32.

S8ter8 · Answer

Yes they are BLE devices. RPi is probably the best choice.

Some send data after a measurement (well twice a day) and some send data every few seconds. There will be about 30 such devices within range of the receiver alone - is it realistic to connect that many at once? I am mainly asking about those transmitting in real time. Can the module handle this?

In addition, I need to send updates to the device if the list of devices changes.

TvWidget · Answer

Two modes of operation are possible with BLE devices: connected and connectionless. In the former, the master device establishes a physical connection with some sensor and reads data from it. Here, it is necessary to know the MAC address and what to read and how. In the second mode, the sensor periodically sends a so-called broadcast frame, e.g. every 1 second. It contains its MAC address. It can also contain additional information, e.g. measurement data. A smartphone, PC, BT gateway, etc., as a result of the scanning operation (searching for BT devices), receives such frames from all sensors in the vicinity. What further happens with the information contained in the received frames depends on the software.
In BT5.0, the broadcast mode has been expanded. Many new functionalities have been introduced.

S8ter8 · Answer

This is very good news. So when I send a frame, the devices that can start sending data and such a receiver can receive data from several devices at once, yes? Is there any limitation?

I would preferably send out the device names themselves and receive the data along with the MAC.

There will be several receivers and not always this one particular device will be within range of one particular receiver.

Do you think that here on the group it would be possible to have someone write such a receiver? Better an RPi or an android phone?

TvWidget · Answer

Sending basic broadcast frames is a fundamental functionality of the BLE standard. There is no formal limit on the number of frames received. However, bandwidth and device capabilities are always organic. In other words, as the number of senders increases, the probability of receiving a given frame decreases. That is, some of the transmitted frames start to get lost. In most applications, this does not bother you at all.

I used the term "basic frame" above. It contains the most important thing, i.e. the MAC address. There may also be additional frames. Sensors are usually battery-powered. Any radio activity requires energy. It was therefore decided that there is no point in sending unnecessary data all the time if no one is receiving it. E.g. a smartphone activates active scanning. The sensor knows this and can send additional frames in addition to the basic one, e.g. containing the name of the device.

S8ter8 · Answer

what if we do not have the MAC?
Nowadays I search for devices by their ID because I know what they are transmitting. The problem with the MAC address is that a compatible but unknown device may not be in range (because I do not know the MAC). This is not the case when a user buys such a device and I do not know about it. I have to download the data anyway because I know the user but I do not know the MAC.

How do I create/where do I buy a gateway that takes data from specific devices?

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