🔌 Installer Guide

Coin Vendo Wiring & Flashing

The plug-and-play coin board — it does everything the standard board does (a coin credits the customer on the portal) plus prints a WiFi voucher code for walk-ups with no phone. Wire it, flash it, power on — it auto-connects to the BaiFi router.

Connection diagram

Signal wires from the ESP32 to each part. Power & ground detail is in the cards below.

Signal / GPIO I²C (LCD) 5V power 12V power GND (common)

Exact connections

Every wire, part by part. Left = ESP32 pin, right = where it goes.

🪙Coin Acceptor

Universal acceptor, set to 1 pulse = ₱1, NC mode.

GPIO27SIGNAL / COIN
12V +12V supply +
GNDcommon GND

🖳LCD 20×4 (I²C)

I²C backpack, address 0x27.

GPIO21SDA
GPIO22SCL
5VVCC
GNDGND

🧾Thermal Printer

58mm serial (TTL). Own 5V · 2A supply.

GPIO17printer RX
5V · 2Aprinter VH / +
GNDcommon GND

⏺PRINT Button

Momentary push button.

GPIO25button leg 1
GNDbutton leg 2

🔌Power

Tie all grounds together (mandatory).

5VESP32 5V/VIN + LCD
12Vcoin acceptor
5V · 2Aprinter (separate)

Flash the firmware

Use the free NodeMCU PyFlasher app — it works for both boards. Fill it in like this:

1pick the Serial port2Browse to the .bin3Flash mode = DIO4Flash NodeMCU

NodeMCU PyFlasher

Serial portCOM3Reload1

Firmwarecoinslot_esp32_lcd_MERGED.binBrowse2

Offset0x000000

Baud rate115200

Flash modeDual I/O (DIO)3

Erase flashnoyes, wipes all data

Flash NodeMCU4

For the ESP8266 board: same window — just Browse to coinslot_esp8266.bin instead (Offset stays 0x000000).

🧰What you need

• A USB data cable (not a charge-only one)
• USB driver: CH340 or CP2102 (whichever chip your board has)
• NodeMCU PyFlasher — free, works for both boards (Windows / Mac)

🪙ESP32 board (LCD + printer)

Firmware: coinslot_esp32_lcd_MERGED.bin

Open NodeMCU PyFlasher, plug the ESP32 in via USB
Serial port → pick the board's COM (click Reload if empty)
Browse → coinslot_esp32_lcd_MERGED.bin · Offset 0x000000
Baud 115200 · Flash mode DIO · Erase yes (wipes all data) → Flash NodeMCU

🔌ESP8266 board (standard)

Firmware: coinslot_esp8266.bin

Open NodeMCU PyFlasher, plug the ESP8266 in via USB
Serial port → pick the board's COM (click Reload if empty)
Browse → coinslot_esp8266.bin · Offset 0x000000
Baud 115200 · Flash mode DIO · Erase yes (wipes all data) → Flash NodeMCU

When it shows Done, unplug, wire it per the diagram above, and power on — the board auto-connects to the BaiFi WiFi. No settings, no config.

Before you power on

1
Common ground is a must. ESP32, coin acceptor, printer and every supply must share GND, or nothing reads correctly.
2
The coin signal line is 5V — drop it to 3.3V with a divider or level shifter before GPIO27 (GPIO27 is 3.3V only).
3
Give the thermal printer its own 5V · 2A supply — it draws big current spikes that will brown-out the ESP32 if shared.
4
Set the acceptor to 1 pulse per ₱1 (₱5 = 5 pulses, ₱10 = 10 pulses).
5
No config needed: firmware has the BaiFi-IOT WiFi + coin secret baked in — flash, power on, done.

Pinout reference

ESP32 pin	Wire	Goes to
GPIO27	signal	Coin acceptor SIGNAL
GPIO25	signal	PRINT button → GND
GPIO17	TX2	Thermal printer RX
GPIO21	I²C SDA	LCD SDA
GPIO22	I²C SCL	LCD SCL
5V / GND	power	ESP32, LCD, common ground

The board auto-decides per coin: a portal customer on screen → credits their session; otherwise → piles up for the PRINT button.

Standard coin board (ESP8266)

The plain BaiFi coin board (no LCD/printer) uses this fixed pinout.

ESP8266 pin	Goes to
GPIO2 · D4	COINSLOT IN (coin pulse)
GPIO4 · D2	RELAY → acceptor 12V
GPIO15 · D8	INSERT LED