NodeMCU fade
An LED breathing on an ESP8266, which has no PWM hardware at all: the core moves the pin itself, and the range is 0 to 1023. The whole build, a NodeMCU ESP8266 and 2 more parts, runs here in your browser on the firmware below; open it in the editor to change the wiring or the code and run it again.
Runs in your browser. Free, and no account needed.
The code
The firmware exactly as the editor opens it. Change a line there and press Run: it compiles in the browser.
// Fade: an LED on D1 breathing, on the software PWM.
//
// There is no PWM hardware on an ESP8266: analogWrite moves the pin from a
// timer handler. Two things follow. The range is 0 to 1023, not 0 to 255, and
// the core wakes twice a period to do the work, so a fading LED costs
// something here where on an ESP32 it costs nothing.
const int kLed = D1;
void setup()
{
pinMode(kLed, OUTPUT);
analogWriteFreq(1000);
}
void loop()
{
for (int duty = 0; duty <= 1023; duty += 8) {
analogWrite(kLed, duty);
delay(4);
}
for (int duty = 1023; duty >= 0; duty -= 8) {
analogWrite(kLed, duty);
delay(4);
}
}
Parts list
4 parts, plus the jumper wires. Every one is in the editor's parts bin.
How it is wired
3 connections, pin by pin, read from the circuit itself. Each line is one set of pins joined together, by a jumper wire or a breadboard strip.
- ESP8266 NodeMCU V1.0 pin D1; Resistor, 220 Ω pin 1
- Ground: ESP8266 NodeMCU V1.0 pin GND; LED, yellow pin C
- Resistor, 220 Ω pin 2; LED, yellow pin A
Change it and keep it
Open it in the editor, change the circuit or the code, and keep your version in a free account.