Send data from one ESP32 to another

Edgars Sturms
Posts: 3
Joined: Sun May 05, 2019 11:41 pm

Send data from one ESP32 to another

Postby Edgars Sturms » Sat May 18, 2019 6:59 pm

Hi,

I'm currently trying to implement indoor positioning system using 4 ESP32 microcontrollers where one board is a 'master' and other three are 'slaves'. The slaves are configured as AP, so I can use 'HTTP_GET' request from 'master' to get the needed data from 'slave' nodes. So far so good.. But the problem rises when I try to get the position of a BLE beacons. Because I need to scan beacons to get their RSSI values to each ESP32 and also transfer this data then to 'master', I need to use both WiFi and Bluetooth libraries. The main problem WHY I cannot use this approach/architecture is that my ESP32's has not enough flash memory. :( The specification told that it'll have 4x more memory..

The following error is shown:
"Sketch uses 1661386 bytes (126%) of program storage space. Maximum is 1310720 bytes."

I also tried to include only needed header files, but it also didn't do much..

The question:
How can I transfer small data like 10bytes or so from each 'slave' to 'master' without adding HUGE libraries ?
I know that it can be done using bluetooth signals but I couldn't find understandable samples. I'm beginner at this.. :'(
This is for my bachelor theses, not much time left.. please help!

BR,
Ed

rodmcm
Posts: 38
Joined: Sat Sep 02, 2017 3:31 am

Re: Send data from one ESP32 to another

Postby rodmcm » Mon May 20, 2019 8:51 am

If you search this site you will find that using WIFI with Bluetooth is almost impossible due to the large compiled size of the two together.
I have overcome this only by using two ESp32'a one for the WIFI connection and one for the bluetooth with a standard hardwired serial in-between
There seems to be a lot of issues with ESP32 in combined usage WIFI and I2C is another one..

dsyleixa
Posts: 7
Joined: Mon May 20, 2019 8:33 pm

Re: Send data from one ESP32 to another

Postby dsyleixa » Tue May 21, 2019 10:21 am

you may also use UART RX/TX between both ESPs, but not wired by cables but with 2 paired HC05 modules in between for WL transmission, using just the standard Serial communication though.

flywire
Posts: 2
Joined: Fri Jun 28, 2019 4:27 am

Re: Send data from one ESP32 to another

Postby flywire » Fri Jun 28, 2019 4:30 am

Hmm, connect external bluetooth modules to bypass integrated bluetooth modules. Sucks

ESP_Sprite
Posts: 2916
Joined: Thu Nov 26, 2015 4:08 am

Re: Send data from one ESP32 to another

Postby ESP_Sprite » Fri Jun 28, 2019 4:53 am

The maximum size is limited by the partition layout of your flash. You can change that; some quick Googling turns up e.g. this.

plajjd
Posts: 38
Joined: Thu Jul 05, 2018 11:47 pm

Re: Send data from one ESP32 to another

Postby plajjd » Tue Jul 02, 2019 10:45 pm

We are successfully using WiFi and BLE on the same ESP32 device. But we did have to increase the flash partition size to 1.3 Meg.

Phil.

flywire
Posts: 2
Joined: Fri Jun 28, 2019 4:27 am

Re: Send data from one ESP32 to another

Postby flywire » Mon Jul 08, 2019 1:15 pm

An example would be nice.

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