I have the TTGO LoRa OLED V1.
The example creates SDA_OLED and SCL_OLED at 4 and 15, and the OLED works.

But the Uv sensor is giving 65535, the error code for I2C. I get it when only the SDA wire is plugged in to 21. The pinout says 21 is SDA and 22 is SCL.

Same with 21 and 22, the I2C default.
And I read somewhere that an LED on pin 22 made them move SCL to 23, but that doesn’t work either.

And I can’t upload when I have 3V connected to the VEML6070 Uv chip.

The chip is removed, and I’m still getting 65535.

Just added a moisture sensor at pin 36, and it doesn’t work.
Anybody got any ideas?

Assuming you use board = ttgo-lora32-v1 in the platformio.ini,then the variant pins

will be chosen, so that should be right

What does the Arduino Playground - I2cScanner say what devices are found on the default I²C bus when that UV sensor is connected?

Wow, that’s an interesting document.

I haven’t tried the I2C scanner, because I haven’t found a working pair of pins.
I have experience with this chip. I’m confident in the addresses and all that. Getting the address and getting data are about the same.

But I’m battening down ahead of Hurricane Ian. It’s coming up overland, so I don’t expect it to hit the mid-Atlantic with huge force, but it will be windy and rainy for a few days. So it’ll be a few days before I get back to this.

I really want this to work. I’ve seen projects online, but they may be the TFT version. Can’t imagine the pins don’t work. I should have seen signal from the moisture sensor at GPIO36. And that’s the right pin:
static const uint8_t A0 = 36;

This is going to replace ESP-Now Pod1, with a moisture sensor that displays on the OLED. I’m going to put it in a pot plant. And I just got a lightning sensor.