Recent posts

#21

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

#22

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.

#23

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.

#24

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

#25

ESP32 / Re: ESPHome issue with UART

Last post by ju - October 03, 2025, 05:52:17 PM

Thanks for the suggestion!
Yes, I've used esp32-gateway as a board config, with esp-idf as a framework.

For a moment there, I thought you had saved me! On my first attempt I could see *something* on the UART RX, garbled noise, but something!
But upon further inspection, it was just a bad solder joint causing intermittent connection.
Reseating a resoldering them got me back to my initial issue: I can TX, I have no idea if the other end receives anything, and I do not RX anything... :-/

#26

ESP32 / Re: ESPHome issue with UART

Last post by LubOlimex - October 03, 2025, 04:48:30 PM

Try with GPIO16 and GPIO32, pins #11 and #13 from CON1. Make sure to define them in the code for UART operation.

Did you use the esp32-gateway for board config?

#27

ESP32 / Nominal/max forward current of...

Last post by 981380 - October 03, 2025, 11:32:15 AM

Is there a datasheet for the SSR-DIN-10A-480VAC or at least what is the nominal and max forward current for the trigger?

Sorry, couldn't find a more suitable forum topic area.

#28

ESP32 / ESPHome issue with UART

Last post by ju - October 03, 2025, 11:26:32 AM

Hi folks!

So I've been scratching my head a lot the past day or so, maybe someone here can help me out!

I have a working ESPHome project running on an Olimex ESP32-POE-16MB Rev. L1, I don't need POE for this, nor do I need the Ext connector, so I decided to try to move the project to an Olimex ESP32-Gateway-EA Rev. I
I don't use Ethernet on either board.

Since I changed boards, I cannot get UART to work at all.

I used GPIO13 for TX and GPIO5 for RX on the ESP32-POE without issues.
On the ESP32-Gateway, I've so far tried GPIO16&17, GPIO12&13, GPIO4&13: I don't get any response from UART anywhere.
I've used the same cable for both boards, and now switched back to the ESP32-POE, still the same cable, and everything still works on that board.

Is there something I need to do to make UART work on the ESP32-Gateway?

Thanks a lot!

#29

New Products release / Join our Special Creative Even...

Last post by olimex - October 02, 2025, 11:36:40 AM

Join our Special Creative Event This Saturday from 14.00-16.00! We will have Soldering party and make art with scrapped electronic components.  https://olimex.wordpress.com/2025/10/02/join-our-special-creative-event-this-saturday-we-will-have-soldering-party-and-make-art-with-scrapped-electronic-components/ #soldering #art #plovdiv #olimex

#30

ESP32 / Re: ESP32-PoE-ISO how to set m...

Last post by chrismacp - September 28, 2025, 09:49:24 PM

I'd really like to change the mac address on the ethernet interface as well. Looks like it's not possible unless you follow your burn in instructions above. I was hoping it didn't come to that.

Looks like support for changing the mac through software is only supported for the WIFI interfaces now