Vext control and Battery level detect

rodri16 · June 10, 2019, 8:55am

Hi I would like to know how to use I2C and Battery level detect with pin 21 as pin 21 is SDA

rodri16 · June 10, 2019, 1:35pm

I cannot use pin 13 ADC2_4 while Wifi is beibg used. I am programming in Arduino IDE

fishlee · June 11, 2019, 4:13am

I2C Example:

HelTecAutomation/Heltec_ESP32/blob/master/examples/ESP32/I2C1_Scanner/I2C1_Scanner.ino

/* Heltec Automation I2C scanner example (also it's a basic example how to use I2C1)
 *
 * ESP32 have two I2C (I2C0 and I2C1) bus
 *
 * OLED is connected to I2C0, so if scan with Wire (I2C0), the return address should be 0x3C.
 *
 * If you need scan other device address in I2C1...
 *		- Comment all Wire.***() codes;
 * 		- Uncomment all Wire1.***() codes;
 *
 * I2C scan example and I2C1
 *
 * HelTec AutoMation, Chengdu, China
 * 成都惠利特自动化科技有限公司
 * www.heltec.org
 *
 * this project also realess in GitHub:
 * https://github.com/HelTecAutomation/Heltec_ESP32
 * */

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Battery detects and measures example:

github.com

HelTecAutomation/Heltec_ESP32/blob/master/examples/ESP32/ADC_Read_Voltage/Battery_power/Battery_power.ino

/*
 * HelTec Automation(TM) Electricity detection example.
 *
 * Function summary:
 *
 * - Vext connected to 3.3V via a MOS-FET, the gate pin connected to GPIO21;
 *
 * - Battery power detection is achieved by detecting the voltage of GPIO13;
 *
 * - OLED display and PE4259(RF switch) use Vext as power supply;
 *
 * - WIFI Kit series V1 don't have Vext control function;
 *
 * HelTec AutoMation, Chengdu, China.
 * �ɶ��������Զ����Ƽ����޹�˾
 * www.heltec.cn
 * support@heltec.cn
 *
 * this project also release in GitHub:
 * https://github.com/Heltec-Aaron-Lee/WiFi_Kit_series

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il_caprone · August 4, 2019, 9:56pm

The reading battery power example don’t work for me.

The battery level is over 100% when only a lipo battery is connected.
I believe the following variable is wrong float XS = 0.00225;
It seems calculated considering that 3.3V is the max value that internal ADC can read.

Reading other posts the max ADC value is 2.5V. Considering that: float XS = 0.001953 make it works. Battery level 100% when the battery is fully charger.

Saber · August 5, 2019, 10:04am

When ESP32 uses WI-FI, the internal ADC2 is occupied. Therefore, the application can only use ADC2 when the Wi-Fi driver is not started.

https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/adc.html