16 votes

Is MQTT protocol appropriate for transmitting sensor readings over BLE?

MQTT has to run over TCP/IP (I can't remember if it's actually in the spec or if just enough assumptions are made to make it so) but its sister protocol MQTT-SN can be run over nearly any protocol ...
hardillb's user avatar
  • 12.6k
13 votes

Are there any Bluetooth LE light dimmers with open APIs?

In general Bluetooth equipment always comes with a proprietary app for your phone... I think that if you want to have the control over your Bluetooth switches, you might want to take a look at ...
Goufalite's user avatar
  • 3,756
11 votes

Is MQTT protocol appropriate for transmitting sensor readings over BLE?

Arguably, you'd be better off doing a simple mapping of the data from BLE paradigms to MQTT, rather than trying to literally send MQTT over BLE. BLE generally exchanges data in the form of ...
Chris Stratton's user avatar
10 votes

Speed limitations on moving sensors

Reliable communications between digital devices requires some degree of signal processing to synchronize the data and the timing (clock). Adding relative motion between the transmitter and receiver ...
Jim's user avatar
  • 201
8 votes
Accepted

Is Bluetooth a good enough protocol for "lost my keys" beacons?

The problem is essentially one of receivers and of power. A "find my keys" type of beacon needs to be small enough to attach to your keychain and you probably don't want to have to regularly ...
HBruijn's user avatar
  • 396
8 votes

Suitable wireless technologies for high density industrial IoT

Your challenge is handling the throughput demands with channel contention. Your devices are all close enough that you need to assume they are all potential interferers to each other so you will need ...
Sean Houlihane's user avatar
7 votes

Optimal Wireless Technology for High Data Rate & Low Latency IoT Application

Latency vs Rate a low-latency (10 Hz) type of IoT application This is a conceptual error. Latency and Rate are largely independent. You could have a system which recorded thousands of readings ...
Chris Stratton's user avatar
7 votes

Is Bluetooth a good enough protocol for "lost my keys" beacons?

This is an unusual use-case where the data throughput which you require is really low - range and low power are the driving factors. This points in the direction of a low data-rate, narrow band ...
Sean Houlihane's user avatar
7 votes

Are there any Bluetooth LE light dimmers with open APIs?

The closest to an answer that I can come to is this list of products supported by openhab. It doesn't identify which products use Bluetooth LE, but does identify products (indirectly) where the ...
Sean Houlihane's user avatar
7 votes

Speed limitations on moving sensors

This is a question on basic physics. Provided all parts of your network are moving at the same speed (give or take) then there is no impact of being in a moving reference frame (as we all are on Earth)...
Sean Houlihane's user avatar
6 votes

Is Bluetooth a good enough protocol for "lost my keys" beacons?

I would like to say that Yes, Bluetooth is a good candidate for indoor positioning. Depending on how good positioning you want, of course. If you have Bluetooth beacons scattered over your house it ...
Bex's user avatar
  • 673
6 votes
Accepted

How do the AirPods communicate with the phone?

Apple is keeping the technology it uses for AirPods under wraps, hence my answer is best attempt based on the information in public domain. Do both Airpods use Bluetooth technology? Yes, because ...
sob's user avatar
  • 2,610
6 votes

Setting a device clock with BLE

Have you looked at Web Bluetooth? This can be used to write to the the device without needing a native client app just to set the time. There is support in Chrome on most platforms and other browsers ...
hardillb's user avatar
  • 12.6k
6 votes

Setting a device clock with BLE

Since you don't intend to further communicate with the partner device I guess the precision of the set time is okay for you in a precision range of a few seconds. If you want to get more precise you'...
Helmar's user avatar
  • 8,430
6 votes

Protocol for over 300 metres and minimum of 20 kbytes datarate?

I would recommend some sort of mesh network, as obviously plain old WiFi or BT won't cover those distances. Zigbee is as good a candidate as any. For hardware, AdaFruit does some good wearables, ...
Mawg's user avatar
  • 3,110
5 votes

List of BLE hardware devices & what BLE services that they support

I think the only place that may have such a list would be the Bluetooth SIG as they will know what products are certified. Otherwise each profile might list a few examples of devices that implement ...
hardillb's user avatar
  • 12.6k
5 votes
Accepted

Rapid pairing of Bluetooth low energy interface

If two devices are already bonded and one of them is mains powered, you should be able to establish the connection in way less than 1 sec given that the mains powered device is constantly scanning or ...
MaliceInWonderland's user avatar
5 votes

Is there an IoT device which has Bluetooth, GPS, a USB port and which can support a module for an alarm?

SIMCOM SIM808 module seems to meet the requirements for your device. Bluetooth: compliant with 3.0+EDR Specification for GPS Receiver type 22 tracking /66 acquisition -channel ...
sob's user avatar
  • 2,610
5 votes

Looking for direction to find a specific hardware

The flic button from shortcut labs meets most (but not all) of your requirements. (not cheap and the light only comes on when the button is pushed iirc, but might be hackable/fixable at the firmware ...
hardillb's user avatar
  • 12.6k
5 votes
Accepted

How does transmit power influence the accuracy of beacon sensor readings?

Bluetooth (and pretty much every other transmission protocol in contrast to sensors like radar) are based on digital protocols. This means that the signals are both binary, and protected by error ...
Sean Houlihane's user avatar
5 votes
Accepted

Bluetooth Direction Finding - do I understand it correctly?

The way Bluetooth direction finding works is described in this document. There are two scenarios: AoD (Angle of Departure): Sending device sends a "direction finding signal" Sending device is ...
jcaron's user avatar
  • 2,283
4 votes

Speed limitations on moving sensors

For a stationary spinning wheel: when the antenna is mounted co-axially onto the hub of the wheel (assuming that the internal, typically folded BT antenna has been replaced with a straight wire ...
Klaws's user avatar
  • 149
4 votes

What would be the best way of authenticating users without password or username?

If you are planning to use cheap android tablets, you should do some survey to understand what technologies are possible options for authentication. Besides wifi and bluetooth connectivity, most of ...
gabonator's user avatar
  • 226
4 votes

Distance calculation based on RSSI value

First you have to know that only one RSSI gives you nothing about distance. Because it may vary from device to device. To calculate distance you must know "calibrated" value. For example, RSSI value ...
Mike Petrichenko's user avatar
4 votes

Suitable wireless technologies for high density industrial IoT

Your best bet is DASH7. It's pretty unknown even among nerds, but if you want a solid industrial stack, DASH7 it is. In case you haven't heard of DASH7 before, it's the official IoT standard of all ...
typo's user avatar
  • 249
3 votes

What would be the best way of authenticating users without password or username?

You can consider attaching pcProx® Plus RFID readers with the machines, 1 per machine. You can use RDR-80581AK8 SKU. It is powered by 5V external power supply and supports RS232 for sending data in ...
sob's user avatar
  • 2,610
3 votes

What would be the best way of authenticating users without password or username?

Possibly cheaper than a tablet would be a Raspberry Pi and a USB NFC reader or a NFC Hat. It's not clear what you mean by machine, but if you mean just another computer then both Linux and Windows ...
hardillb's user avatar
  • 12.6k
3 votes
Accepted

Unable to receive response to AT commands after switching from data mode to command mode

After a while of repetitively going through the code and my logic with no luck, I finally decided to probe the signals and check the timing of the 1-second silence preceding and succeeding the escape ...
Vinay Divakar's user avatar
3 votes

Is there an IoT device which has Bluetooth, GPS, a USB port and which can support a module for an alarm?

Shameless plug In about a years time you can get an nRF91 + nRF52840 combo. LTE(CATM1 and NbIoT), GPS, BLE, USB, 802.15.4, etc, that uses a fraction of the power of current devices, and got plenty of ...
MaliceInWonderland's user avatar
3 votes

Maximum Bluetooth LE devices near each other without interference

If you add som randomness to the transmissions you'll be fine. Like 2min +/- random number between 1-10 seconds. You might not even need to do that. As some else have already mentioned the low ...
MaliceInWonderland's user avatar

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