New answers tagged

1

The esp8266 boot configuration pins 0, 2, 15 require a pull-up/pull-down to ensure the required state at boot. The board (NodeMCU in this case) has pull-up resistor on io0 and io2 and a pull-down resistor on pin 15. The MCU pins io0, io2 and io16 are the NodeMCU pin D3, D4 and D8. You can use this pins in the sketch, but only to attach devices which are not ...


1

standard current you can draw from a usb port is 500 mili ampere with 5 volt(you may get even more but it is not recommended) . so if you want to calculate sensors are very low current about 1~2 mA(but you must check out datasheet) turbidity for example draws 30 mA temperature ds1820 is 1 mA flow is up 2 mA the LEDs based on resistors series with them ...


0

Sensors don't usually require that much current and a usb port should be able to handle 4 leds and the MCU without a problem. If you are using an Apple laptop it will disable the usb port temporarily if you draw too much current from it. Some PC laptops probably do the same.


0

Not sure if it possible in your case, but you might send and ID with it which you increase every time the button has been (really) clicked (thus not refreshed). On the receiver side, check if the ID is already received, if yes, do not execute it.


0

in your nodemcu use void loop() { if(s.readBytesUntil('\n',data ,2)>0) Serial.println(data); delay(1000); } Serial.readBytesUntil(character, buffer, length) Serial.readBytesUntil() reads characters from the serial buffer into an array. The function terminates (checks being done in this order) if the determined length has been read, if ...


1

If you send "12" you send 4 characters/bytes: '1', '2' and a new line which is two characters: ('\r', '\n'). On the receiver side you check for two characters (not the new line), so you should take it into account. Actually, since you will eventually reach "100" you will receive 5 characters ('1', '0', '0', '\r', \'n'). So it is better to change the ...


0

Have you checked the device's Scratchpad CRC Idk how to. How is your device hooked up (diagram) Device is hooked up in normal mode, right like in this pic DS18b20 (waterproof) is located on top of the boiler in a special pit for measuring temperatures, there are definitely no any sort of microwaves here, and the temp is not higher than 80C. I'll try ...


0

Discarding (potentially) bogus readings could help as a last resort, but something's going on to cause those bogus readings. You'd be better off finding and fixing that than finding a work-around. These are pretty stable devices and you shouldn't see more than a couple of LSB (a few 1/4 degC). I'm inclined to suggest noise pickup on the one-wire bus but the ...


0

To make that work you'd need to connect the HV connection to the Vin of the NodeMCU (as well as to the relay board) which should be the 5 V coming form the USB port. You'd also need to connect the GND on the HV side to the GND of the NodeMCU.


0

you can try something like this int first_space = request.indexOf(' '); // location of the first space int second_space = request.indexOf(' ', first_space); // the next space after first String query_arg = request.substring(first_space,second_space);


0

I had the same problem, when i tried to connect to my home wifi i got stuck with just printing dots and never could connected. First of all i though that my ssid or password had a typo, but it hadn't. Then i changed the nodemcu and the problem persisted. But when i tried to connect to other wifi it worked. So the problem was in my modem/router.So i changed ...


0

I am new to nodemcu. When I was using ESP8266WiFi.h, I got the error "Error compiling for board NodeMCU 1.0 (ESP-12E Module)" which said that Multiple libraries were found for ESP8266WiFi.h. I solved by simply put the void loop(){} empty function at the end of my code. Now It's working...


0

This answer is the summary of the comments of the question. The idea of the solution was originally mentioned by @Majenko. You powered the shield with about 6 Volts. The statement analogWrite(PWMA, 5); gives you (5/1024) ~ 0.5% of this 6 Volts at the output pin PWMA. This 0.03V are not enough to drive the motor. You should use at least 3 Volts to drive ...


0

void wifi_connect(){ WiFi.mode(WIFI_OFF); //Prevents reconnection issue (taking too long to connect) delay(1000); WiFi.mode(WIFI_STA); //This line hides the viewing of ESP as wifi hotspot //WIFI_STA It's very important !!!! WiFi.begin(ssid, password); //Connect to your WiFi router while(WiFi.status() != WL_CONNECTED){ delay(...


Top 50 recent answers are included