Internet weather station (OLED)
The board is really online — inside the sandbox internet. The ESP32 joins Wi-Fi, resolves api.weather.test with a real DNS lookup, and GETs a weather JSON over a genuine TCP socket, rendering the report and a live UTC clock (from a second REST call) to the OLED. Everything is deterministic and offline — the sandbox mocks the services — and the board’s Wi-Fi inspector can switch a signed-in Pro bench to the real internet. Follow every lookup and HTTP exchange in the 📡 Sniffer.
How it works
The ESP32 joins BreadboardNet and talks to the simulator's sandbox internet: a deterministic, fully offline mock of the real thing built into the emulated network core. The script does a real DNS lookup for api.weather.test (the sandbox resolver answers for any name), opens a genuine TCP socket, and sends a plain HTTP GET; the mock weather service replies with a JSON report, and a second request to /time reads the sandbox's virtual clock. MicroPython parses both with the json module and paints the report — location, temperature, humidity, conditions — plus the live UTC time onto the SSD1306. Because the services are mocked in-core, the demo runs signed-out, offline, and reproducibly; on a signed-in Pro bench, the Wi-Fi inspector's egress toggle points the very same sockets at the real internet through the secure gateway.
What's on the bench
- Battery
- ESP32-C3
- OLED 128×64
How it's wired
- hole a10→hole B-5
- hole a11→hole B+5
- hole a40→hole B-9
- hole a41→hole f10
- hole a42→hole g11
- hole a43→hole b20
The code
This MicroPython script runs on the emulated board every boot; edit it in the Code tab.
from machine import I2C, Pin import framebuf, time i = I2C(0, scl=Pin(9), sda=Pin(8)) buf = bytearray(1024) fb = framebuf.FrameBuffer(buf, 128, 64, framebuf.MONO_VLSB) for c in b'\xae\xd5\x80\xa8\x3f\xd3\x00\x40\x8d\x14\x20\x00\xa1\xc8\xda\x12\x81\xcf\xd9\xf1\xdb\x40\xa4\xa6\xaf': i.writeto(0x3c, bytes([0, c])) def show(): i.writeto(0x3c, b'\x00\x21\x00\x7f\x22\x00\x07') i.writeto(0x3c, b'\x40' + buf) import network, socket, json w = network.WLAN(network.STA_IF) w.active(True) fb.fill(0); fb.text('joining WiFi...', 0, 28); show() w.connect('BreadboardNet') while not w.isconnected(): time.sleep_ms(100) def fetch(host, path): # Real DNS against the sandbox resolver, then a genuine TCP socket. addr = socket.getaddrinfo(host, 80)[0][-1] s = socket.socket() s.connect(addr) s.send(('GET ' + path + ' HTTP/1.0\r\nHost: ' + host + '\r\n\r\n').encode()) r = b'' while True: c = s.recv(256) if not c: break r += c s.close() return json.loads(r.split(b'\r\n\r\n', 1)[1]) n = 0 while True: wx = fetch('api.weather.test', '/weather') t = fetch('worldtimeapi.test', '/time') n += 1 print('wx', n, wx['temperature_c'], 'C,', wx['conditions']) fb.fill(0) fb.text('INTERNET WEATHER', 0, 0) fb.hline(0, 10, 128, 1) fb.text(wx['location'][:16], 0, 14) fb.text('%s C rh %d%%' % (wx['temperature_c'], wx['humidity']), 0, 26) fb.text(wx['conditions'][:16], 0, 38) fb.text(t['utc_datetime'][11:19] + ' UTC #%d' % n, 0, 52) show() time.sleep_ms(2000)
Try this
- Watch the last line of the OLED: the UTC clock and request counter advance on every 2-second refresh.
- Open the 📡 Sniffer and follow a full round trip — DNS query and answer, TCP SYN/ACK, the GET, the JSON reply.
- Edit the script in the Code tab to fetch '/api' (the mock cloud dashboard) or POST to '/echo' instead.
- Click the ESP32 and look at the top of its Wi-Fi inspector: that's where a Pro bench can switch from the sandbox to real internet access.
