Transmission and Reception time of two ESP32

[manuellacoliveira]

Hi,

I need to know the transmission and reception time between two ESP32 by bluetooth. Can someone help me with this subject ?

[kolban]

I doubt there is going to be a published figure. My best recommendation would be to measure it. If we assume App A which is a BLE server that has a characteristic and App B which is a BLE client that wishes to change the value of the characteristic then the answer will be something along the lines of:

path length of B + transmission time + path length of A.

This liable to be a gross over simplification as we don't know if transmissions from B happen immediately nor do we know if there are pollings going on in A. There are also re-transmission possibilities and network radio latencies based on congestion.

Maybe turn the question around. Do you have an absolute minimum duration from your sending app ending its transmission to when your receiving app must have received the same data?

[GDX1024]

Hi, manuella and I are working together.

We're working with some robots for a Very Small Size Soccer (VSSS) team, and we're trying to use the ESP32 to do the communication between the computer and the robots. We will be sending only PWM comands to the motors, two int16 numbers. There are three robots and I was thinking about using one esp32 as a server and send the data to the other three esp32. We must do this about every 10ms, sending two int16 numbers (4 bytes) to three clients every 10ms.

But apparently we can just reach 30ms between the packages to just one client. We are using the Arduino IDE and your (Kolban) library. I don't know if there is some limit we can change, or some hardware limit that turns this task impracticable. Any information will be a great help.

[mickeypop]

Google Search..
Only those devices with the “+HS” suffix are capable of routing data through WiFi and achieving that 24 Mbps speed. “Bluetooth v3.0” devices are still limited to a maximum of 3 Mbps, but they do support other features introduced by the 3.0....

That said; I'm pretty sure ESP32 is BT Version 3 .

A natural question; Can you switch to WiFi? It's generally much faster.

[GDX1024]

Even with 3Mb we should be able to do that. That's 4(bytes)*3(esp)*8(bit)/0.01(second)= 9.6Kb/s + the protocols, but it should not be much bigger.

We are were told that the teams have been having problems with interference using the wifi, and also speed problems, but we are testing that too.

[chegewara]

Hi,
i did some very simple test in arduino. Ive been sending 1 byte every 1 ms, but it caused error, so i decided to add 5ms delay. In my test i used 2 esp32 and logic analyzer. In esp32 ble server in loop when im sending notification im also switching pin value, in esp32 ble client im doing the same (switching pin value) each time when im receiving notification. Result you can see on picture, pin value has been switched every 15 ms:

[awaisahmed]

Re: Transmission and Reception time of two ESP32
Postby chegewara » Fri Mar 09, 2018 11:43 pm

how did you switch the pins ? can i get your tutorial ?