Firmware v1.0.0 · ESP32

FamApp Soundbox

Speaks every FamApp payment out loud and shows the amount on an OLED. Flash it to your ESP32 straight from the browser, with no software to install.

Your browser can't flash devices. Open this page in Chrome or Edge on a computer. Flashing needs a secure page. Open it from the https:// GitHub Pages address.

Connect the ESP32 with a USB data cable first. Works in Chrome and Edge on Windows, macOS, Linux and ChromeOS.

Read the full guide

Supported board

Board	ESP32 Dev Module (classic ESP32, 4 MB flash)
Chip	ESP32 (ESP32-D0WD / WROOM-32)
Display	SSD1306 128×32 OLED, I2C
Audio	MAX98357A I2S amp + speaker

Not for ESP32-S3, C3 or C6 boards.

Wiring

OLED SDA / SCL	GPIO 21 / 22
Amp DIN	GPIO 27
Amp BCLK / LRC	GPIO 26 / 25
Button	GPIO 32 → GND
Amp VIN	5V (louder than 3V3)

How to flash

Plug the ESP32 into your computer with a data USB cable.
Click Flash Firmware and pick the board's port (e.g. COM5, CP210x or CH340).
Click Install. For a first install, keep Erase device ticked.
Wait for Installation complete (about 1–2 minutes), then unplug and replug.

After flashing: setup

On your phone, join Wi-Fi FamApp-Soundbox, password soundbox.
The setup page opens (or go to 192.168.4.1).
Enter your 2.4 GHz Wi-Fi, the Gmail linked to FamApp, and a Gmail app password.
Save. It restarts and beeps when it's ready.

Before you flash

Erase device wipes the saved Wi-Fi and Gmail settings. You'll need to run the setup again.
Use the Gmail app password from myaccount.google.com/apppasswords, never your normal password.
Close the Arduino IDE Serial Monitor and any other program using the port.
For big amounts, always confirm the payment in the FamApp app too.

Using the soundbox

New payment: beep, then "6 rupees received" and the amount on screen.
Press the button: beep, then it repeats the last payment.
Hold BOOT for 10 s while running: erases all settings and opens setup again.

Troubleshooting

No port appears in the list

Try another USB cable. Many cables are charge-only.
Install the USB driver for your board's chip: CP210x or CH340.
Try a different USB port, directly on the computer (no hub).

"Failed to connect" or it gets stuck connecting

Hold the BOOT button, press and release EN/RST, then release BOOT. Click Flash Firmware again.
Close the Arduino IDE, Serial Monitor or any app using the port.
Unplug the amplifier's VIN while flashing if the board keeps resetting.

"Failed to download manifest"

The page couldn't load manifest.json. Make sure you opened the GitHub Pages address (not the file on your computer), then hard-refresh with Ctrl + F5.

Flashed fine, but it doesn't start

Press EN/RST once, or unplug and replug.
If the screen shows SETUP MODE, the settings were erased: run the setup steps above.
Use a strong 5V supply. A weak USB port can make it reset when the speaker plays.

Button says the browser isn't supported

Web flashing uses Web Serial, which only Chrome and Edge (version 89+) support on a computer. Firefox, Safari and phone browsers can't flash.