ESP32 Forum

Posted: **Sun Sep 26, 2021 5:22 pm**

Hi,
I have successfully tested a DS18B20 (Digital Temperature Sensor) with various ESP32 development boards.

I have always used an external pullup resistor of 4.7 kOhm. I have tried to replace it with the internal pullup resistor of the ESP32 without success.

I have used the instruction:

Code: Select all

pinMode(13, INPUT_PULLUP)

or instead

Code: Select all

#include "driver/rtc_io.h"
...
rtc_gpio_pullup_en(GPIO_NUM_13);
rtc_gpio_pulldown_dis(GPIO_NUM_13);

Am I doing something wrong or just the resistor value is not the right one?

Thanks for your attention,

Rafael

Posted: **Mon Sep 27, 2021 1:31 am**

The internal pullup is something like 50K, which is likely too high for the DS18B20.

Posted: **Mon Oct 18, 2021 8:53 pm**

Thanks for your answer, @ESP_Sprite.
Best regards,
Rafael

ESP32 Forum

Internal pullup resistor and DS18B20 (Digital Temperature Sensor): is it possible?

Internal pullup resistor and DS18B20 (Digital Temperature Sensor): is it possible?

Re: Internal pullup resistor and DS18B20 (Digital Temperature Sensor): is it possible?

Re: Internal pullup resistor and DS18B20 (Digital Temperature Sensor): is it possible?