Quick Start: Browser Playground

The CONDUYT Playground lets you flash firmware, write code, and control hardware entirely from your browser. No IDE, no CLI, no drivers.

Prerequisites

  • A supported board: ESP32, Arduino Uno R4, or Raspberry Pi Pico
  • A USB data cable (not a charge-only cable - if your board doesn't show up, try a different cable)
  • Chrome or Edge desktop browser (WebSerial and WebUSB require a Chromium-based browser - Firefox and Safari will not work)

1. Open the Playground

Navigate to /playground. You'll see three panels:

  • Code Editor (left) - Monaco editor with autocomplete for the CONDUYT API
  • Console (top right) - output from log() calls in your code
  • Device (bottom right) - connection status, firmware name, and pin count

2. Flash firmware onto your board

Click Flash in the toolbar. Pick your board below and follow the steps.

ESP32

  1. Click Install CONDUYT Firmware
  2. Chrome will open a serial port picker - select your ESP32
  3. Wait for the installer to finish (it handles bootloader, partitions, and firmware automatically)

If the port picker is empty, try a different USB cable or port. Some ESP32 boards need you to hold the BOOT button during the first few seconds.

Arduino Uno R4

  1. Double-tap the RESET button on the board quickly (two taps within ~500ms) - the "L" LED should start pulsing slowly, which means DFU mode is active
  2. Click Flash Arduino Uno R4
  3. Chrome will prompt for a USB device - select the Arduino DFU device (not a serial port)
  4. Wait for the progress bar to complete

If the "L" LED doesn't pulse, you tapped too slowly. Try again - two quick taps.

On Windows, you may need to install WinUSB drivers via Zadig if no DFU device appears. On macOS and Linux it works without drivers.

Raspberry Pi Pico

  1. Unplug the Pico from USB
  2. Hold the BOOTSEL button (the small white button on the board)
  3. While holding BOOTSEL, plug the USB cable in
  4. Release BOOTSEL - the Pico appears as a USB drive (like a flash drive)
  5. Click Flash Raspberry Pi Pico in the Playground

3. Connect to the board

Close the flash panel. Click Connect in the toolbar. Chrome opens a serial port picker - select your board's port.

The Device panel should update to show:

Connected
Firmware: BasicBlink
Pins: 20

If the connection times out: press the physical RESET button on your board (single tap), wait a second, then click Connect again. If the serial port doesn't appear at all, try unplugging and replugging the USB cable.

4. Run the blink example

The editor comes pre-loaded with a Blink example. Click Run (the play button). You should see output in the Console panel:

[runner] Connected: BasicBlink
LED ON
LED OFF
LED ON
LED OFF
...
[runner] Finished

And the LED on your board should blink. The default LED pin is 13 (Uno R4), 2 (ESP32), or 25 (Pico).

If nothing happens: make sure the Device panel says "Connected" before clicking Run. Check the Console for error messages like "Not connected" or "Timeout".

5. Try other examples

Use the Examples dropdown in the toolbar:

ExampleWhat it doesBoard needed?
BlinkToggle LED on/offYes
Read SensorRead analog pin valuesYes
PingTest the connection round-tripYes
PWM FadeSmooth LED brightness sweepYes (PWM-capable pin)
Raw PacketsLow-level protocol demoNo (runs in-browser only)

6. Write your own code

Clear the editor and try this:

// Set pin 13 as output and blink 5 times
await device.pin(13).mode('output')

for (let i = 0; i < 5; i++) {
  await device.pin(13).write(1)
  log('ON')
  await sleep(300)

  await device.pin(13).write(0)
  log('OFF')
  await sleep(300)
}

log('Done!')

Available APIs

The Playground gives you four globals:

device - board control

await device.connect()                    // open connection (done automatically by Run)
await device.pin(13).mode('output')       // set pin mode: 'input', 'output', 'analog', 'pwm'
await device.pin(13).write(1)             // digital write: 0 or 1
const val = await device.pin(0).read()    // read pin value (analog if mode is 'analog')
await device.ping()                       // round-trip connectivity test
await device.reset()                      // soft-reset the device

conduyt - low-level WASM protocol

const CMD = conduyt.getCMD()                    // command type constants
const pkt = conduyt.makePacket(CMD.PING, 0)     // build a raw packet
const wire = conduyt.wireEncode(pkt)            // encode to wire format
const cobs = conduyt.cobsEncode(wire)           // apply COBS framing

log(...) - print to the Console panel

log('sensor value:', val)
log({ temperature: 23.5, humidity: 51 })

sleep(ms) - async delay

await sleep(1000)  // wait 1 second

Type device. or conduyt. in the editor to see full autocomplete suggestions.

Limitations

  • Browser support: Chrome or Edge only (no Firefox, no Safari, no mobile browsers)
  • USB only: The Playground connects via USB serial. For wireless (BLE, MQTT), use the native SDKs
  • Use await sleep(): Code runs in the main browser thread. Long-running loops without await sleep() will freeze the page
  • Stop running code: Click the Stop button (square icon) in the toolbar

Next steps