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Blink an LED

Your first flow: make an LED blink once a second. It takes three nodes.

Before you start, connect a board that has the Thingstudio runtime installed.

Find your LED's pin

Many boards have an LED you can drive from a GPIO pin. Check your board's documentation for its number. Two common ones:

Board LED pin
LOLIN S2 Mini 15
Raspberry Pi Pico (RP2040) 25

The Pico W and Pico 2 W LEDs are wired through the WiFi chip, not a GPIO pin, so gpio out can't reach them. On those boards, or any board without an LED, wire an LED and a 330 Ω resistor from a free GPIO pin to GND.

Build the flow

  1. Drag a timer onto the canvas. Set interval (ms) to 500.

  2. Drag a function onto the canvas. Replace its code with:

    msg['payload'] = msg['payload'] % 2
return msg

  3. Drag a gpio out onto the canvas. Set pin to your LED's pin.

  4. Wire timer → function → gpio out.

Deploy

Click Compile → Deploy. The LED blinks: on for half a second, off for half a second.

The flow keeps running on the board after you unplug it from your computer and power it another way.

How it works

The timer sends a message every 500 ms. Its payload is a count: 1, 2, 3, and so on.

gpio out turns the pin on for any payload that isn't zero. Wired straight to the timer, the LED would switch on and stay on.

The function node turns the count into 1, 0, 1, 0 — the remainder after dividing by 2. That gives on, off, on, off.

  • Deploy is greyed out: you aren't connected. Click Connect.
  • Deploy fails: the console says why. See Board won't connect.
  • Deploy works but the LED stays dark: check the pin number. Some boards' LEDs light when the pin is off; the LED still blinks, just the other way round.