Recent posts

#71

ESP32 / Re: ESPHome issue with UART

Last post by ju - October 09, 2025, 09:55:53 AM

This is the same 1m USB-C (65w rated) cable I use for everything, but I tried with a 30cm USB-A->C with the same result.

I don't do anything, I plug the board and the (continuously repeating) serial output is what I've pasted!

#72

ESP32 / Re: ESPHome issue with UART

Last post by LubOlimex - October 09, 2025, 08:19:53 AM

Until board resets it works fine, but why does it reset? Is it resetting by itself? If so test with another shorter USB cable and port. Maybe this cable is flawed and doesn't make good contact with the board or doesn't provide enough power.

If you didn't reset it, did you open serial terminal on the COM port of board? Connect GPIO11 and GPIO13 together after you open the terminal and type something to see if it will return echo.

#73

ESP32 / Re: ESPHome issue with UART

Last post by ju - October 08, 2025, 09:37:03 PM

Sorry for the delay, I was only able to test now!
Here's the output on the serial monitor:

Code Select Expand

rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46

rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46

rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46

rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46

rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46

So, I don't think it's working as expected, right?

#74

ESP32 / Re: Nominal/max forward curren...

Last post by LubOlimex - October 07, 2025, 10:30:25 AM

As you can see in the pictures it is BRM-LK10DA solid-state relay (SSR), we are just re-seller. The 25A and 40A versions of the relay are named BRM-LK25DA and BRM-LK40DA.

All variants have control terminal voltage in the 3-32VDC range and control current between 5-20mA.

All variants have output terminal voltage in the 24-480VAC range.

The 10A variant has load current of 10A resistive current of 5A and inductive current 1.5A.

The 25A variant has load current of 25A and resistive current of 12A and inductive current 4A.

The 40A variant has load current of 40A and resistive current of 20A and inductive current 6.5A.

The disconnection current of all variants is under 5mA. Insulation resistance for all is 1000MΩ and on-off time is ≤10ms.

#75

ESP32 / Re: ESP3-S3-LiPo battery charg...

Last post by maunope - October 06, 2025, 01:45:03 PM

Hey!
got it, thanks!

Maurizio

#76

ESP32 / Re: ESP3-S3-LiPo battery charg...

Last post by LubOlimex - October 06, 2025, 01:33:14 PM

It was mainly a design change since high current draw could limit down the current output for other peripherals attached to the board.

Another thing is that the battery charger chip might get very hot since 450mA is near the maximum it can provide.

My advice is to keep it as it is. Notice that it is not a problem to use 3000mA 3.7 Li-Po battery without any changes. It will just charge slower if it is severely discharged.

But of course you can also change R4 to smaller resistor in with 0402 size and it will have higher current for charge. My advice is not to go as low as 2.2k, maybe down to 3.3k (which is 300mA of current for charging).

#77

ESP32 / ESP3-S3-LiPo battery charge cu...

Last post by maunope - October 06, 2025, 12:50:38 PM

Hi!
I've noticed the battery charge current of this model is 100mA only, whereas the older ESP32 had a 2.2kohm R4, resulting in 455mA.

I'm using a 3000mA battery, which I understand is larger than the recommended 1400mA one, I was considering paralleling a resistor to R4 to be able to charge it in around 12h insteda of 30.
I understand the risk of messing things up/damaging my devkit, apart form this, is there any specific reason for esp32-s3 running 100mA instead of 455?

thanks in advance!

Maurizio

https://github.com/OLIMEX/ESP32-DevKit-LiPo/tree/master/HARDWARE/ESP32-DevKit-LiPo-Rev.D

https://github.com/OLIMEX/ESP32-S3-DevKit-LiPo/blob/main/HARDWARE/ESP32-S3-DevKit-LiPo_Rev_B/ESP32-S3-DevKit-LiPo_Rev_B.pdf

#78

A20 / Re: A20 can't boot/start anymo...

Last post by LubOlimex - October 06, 2025, 08:56:47 AM

Is PWR_LED "the red light" should not blink, it is power good indicator. When you apply power it should turn on and stay on. If it blinks it is either lose connection, or bad power supply adapter, or there is some hardware damage with the board. Did you provide 5V DC to the power jack? Maybe try with another power adapter to exclude problems with the physical connection or bad power supply.

#79

ESP32 / Re: ESPHome issue with UART

Last post by LubOlimex - October 06, 2025, 08:21:21 AM

Did you try with simplest UART test? Just create the software serial on the chosen pins and then connect them together (e.g. RX to TX) and then open terminal and see if you get echo when you type something. If there is echo the problem is not with the esp32-gateway.

If there is still a problem, maybe test with Arduino IDE instead. I haven't used esphome a lot but in Arduino IDE serial works. Here is some simple test with instructions for Arduino IDE:

Code Select Expand

/*
  ESP32-GATEWAY Serial Demo
  -------------------------
  Demonstrates using a second UART on GPIO11 (TX) and GPIO13 (RX).

  ESP32 Arduino package installation:
  1. Open Arduino IDE → File → Preferences
  2. In "Additional Boards Manager URLs" add:
      https://espressif.github.io/arduino-esp32/package_esp32_index.json
  3. Go to Tools → Board → Boards Manager
  4. Search for "esp32" and install the package by Espressif Systems
  5. Select your board under:
      Tools → Board → ESP32 Arduino → "Olimex ESP32-Gateway"

 
  Hardware connections:
  - GPIO11 → TX2 (connect to RX of other device)
  - GPIO13 → RX2 (connect to TX of other device)
  - USB → for Serial Monitor (primary UART)
*/

#define RX2_PIN 13  // Receive pin for Serial2
#define TX2_PIN 11  // Transmit pin for Serial2

void setup() {
  // Start USB serial monitor at 115200 baud
  Serial.begin(115200);
  while (!Serial) {
    ; // Wait for Serial Monitor to open
  }
  Serial.println("ESP32-Gateway Serial2 demo starting...");

  // Initialize Serial2 on GPIO13 (RX) and GPIO11 (TX) at 9600 baud
  Serial2.begin(9600, SERIAL_8N1, RX2_PIN, TX2_PIN);
  Serial.println("Serial2 initialized on GPIO11 (TX) / GPIO13 (RX)");
}

void loop() {
  // Send test message periodically via Serial2
  Serial2.println("Hello from ESP32-Gateway Serial2!");

  // If data is received on Serial2, display it on the USB serial monitor
  if (Serial2.available()) {
    String incoming = Serial2.readStringUntil('\n');
    Serial.print("Received on Serial2: ");
    Serial.println(incoming);
  }

  // Echo any text entered in the Serial Monitor to Serial2
  if (Serial.available()) {
    String input = Serial.readStringUntil('\n');
    Serial2.print("Echo from USB: ");
    Serial2.println(input);
  }

  delay(2000); // Delay 2 seconds between transmissions
}

Let me know if the problem persists with Arduino IDE.

#80

A20 / A20 can't boot/start anymore

Last post by gporte - October 05, 2025, 03:47:07 PM

Hi,

some weeks ago my A20-OLinuXino-LIME2-s16M crashed with red light on.

I tried to reboot, unplug/replug charger, reinstall image (base, then minimal) but it is still the same : red light is flashing a while, then stay on. Nothing on screen (pluged with HDMI).

SDcard seems to be ok (I can access it on my laptop).

Have you any idea how I could test if the A20 is dead ?

I have saved the logs on the previous installed that crashed but I have no idea where to search

Thanks !

Guillaume