ESP-WROOM32 Bluetooth Signal Strength

Posts: 2
Joined: Fri Nov 15, 2019 10:54 pm

ESP-WROOM32 Bluetooth Signal Strength

Postby metricToby » Fri Nov 15, 2019 11:09 pm


i have been working on a project where i use a ESP-WROOM32 in combination with a GPS, Accelerometer and a CAN Bus transceiver.

All is working well, except transferring the collected data to my phone using classic Bluetooth. If i move my phone more than a foot (30cm) away from the board i get congestion events. If i put my body between phone and board then the transmission stops all together.
Measurements with an app on my phone revealed that the Bluetooth signal is very weak and not even detectable for my phone from 5 feet (1.5 meter) away.

i tried the following with no luck:
- replace the board
- change power with: "esp_bredr_tx_power_set(ESP_PWR_LVL_P9, ESP_PWR_LVL_P9)"
- ran BLE example and used "BLEDevice::setPower(ESP_PWR_LVL_P9);" to change power
- powered the board from a more powerful source than USB

Does anybody have any suggestions to make this work over longer distances? Nothing crazy but 30 feet (10 meters) would be nice.

Board: ... 163&sr=8-1
IDE: Arduino
App to measure RSSI: ... h&hl=en_US

Thank you

Posts: 2
Joined: Fri Nov 15, 2019 10:54 pm

Re: ESP-WROOM32 Bluetooth Signal Strength

Postby metricToby » Mon Dec 02, 2019 2:18 am

I ordered 4 more boards from different manufacturers, but unfortunately all of them have the same weak Bluetooth Signal Strength.

Can it be that all of them are counterfeits or is the ESP32's Bluetooth really so weak?
If no one can help me with this then i will have to move away from this platform, but i don't really want to. This chip has so many great features all in one package.


Posts: 23
Joined: Mon Jul 29, 2019 3:31 pm

Re: ESP-WROOM32 Bluetooth Signal Strength

Postby bonadio » Sat Dec 07, 2019 12:46 am

Hello Toby

In my current project I had some problems with BT and I found that the way you put the wroom module on your board or what else is close to it has a really big impact on BT performance. Check the esp32_hardware_design_guidelines_en.pdf it has some tips on how to place your board, In my case moving all components away from the antena and placing the module on the right side of my board made a big difference.


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