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Gustavo Murta
Gustavo Murta vor 10 Stunden
Picture of circuit ( ESP32 DEVKIT) : I did my first test with I2C Interface using Arduino IDE. And it works !  I2C scanner based on code of Nick Gammon Very simple ! The I2C clock frequency is almost 100 KHz (97.96 KHz). I can't change this.  NOTE > PCF8574 - max frequency = 100 KHz (does not work with 400 KHz).  PCF8574 Datasheet = Diagram - SDA = GPIO_21 and SCL = GPIO_22 .  Very Important = You MUST use Pullup Resistors of 3K3 ohms. Without then it does not work ! I still do not know, how to configure (Arduino IDE) pullup internal resistors. Change jumpers A0,A1 and A2 to modify address. Default PCF8574 address is 0x20 ( Decimal 32). Picture of circuit diagram: Decoding I2C Pulses with Logic Analyzer : I2C Scanner (Arduino IDE 1.8.5) : [code] // ESP32 I2C Scanner // Based on code of Nick Gammon // ESP32 DevKit - Arduino IDE 1.8.5 // Device tested PCF8574 - Use pullup resistors 3K3 ohms ! // PCF8574 Default Freq 100 KHz #include <Wire.h> void setup() { Serial.begin (115200); Wire.begin (21, 22); // sda= GPIO_21 /scl= GPIO_22 } void Scanner () { Serial.println (); Serial.println ("I2C scanner. Scanning ..."); byte count = 0; Wire.begin(); for (byte i = 8; i < 120; i++) { Wire.beginTransmission (i); // Begin I2C transmission Address (i) if (Wire.endTransmission () == 0) // Receive 0 = success (ACK response) { Serial.print ("Found address: "); Serial.print (i, DEC); Serial.print (" (0x"); Serial.print (i, HEX); // PCF8574 7 bit address Serial.println (")"); count++; } } Serial.print ("Found "); Serial.print (count, DEC); // numbers of devices Serial.println (" device(s)."); } void loop() { Scanner (); delay (100); } [/code] Console IDE (115200 Bps)  rst:0x1 (POWERON_RESET),boot:0x13 (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:2 load:0x3fff0018,len:4 load:0x3fff001c,len:812 load:0x40078000,len:0 load:0x40078000,len:11404 entry 0x40078a28 I2C scanner. Scanning ... Found address: 32 (0x20) Found 1 device(s). I2C scanner. Scanning ... Found address: 32 (0x20) Found 1 device(s).  
ESP32 Digital Voltmeter
andruszd vor 12 Stunden
Water Sensors update Have desidedwhat the float sensor looks like and from the images you can sse how i constructed them + how i have water proffred them (i hope it works ) Have desiced on how the are going to be moiunted and have started mounting the ultrasound sensor. 
Water tank auto level system with fail safe
swisssamuelb vor 13 Stunden
With a lot of material a great solution for three phases. Pimp my band saw.!!! Attention, works only at star connection !!!
Mains Power Driver by MCU DC or PWM
John Cronin
John Cronin vor 1 Tag
Agreed.  They make modularized opto coupled solid state switches that are sealed in UL rated enclosures.   Using them allows you to physically isolate the line power and improve the safety of your project.  Done correctly using a good certified solid state switch "could" meet electrical codes.  Putting a triac on a home made printed circuit will not meet electrical codes.  
Mains Power Driver by MCU DC or PWM
Aggiejeff vor 1 Tag
Ron, Afraid I haven’t received the ESP32 dev sample yet, so I regret that I haven’t gotten very far to date. Thanks for your interest, though! —Jeff
Wireless interface for troubleshooting BACnet MS/TP