Coin vibration motor module
Coin vibration motor module pinout (IN, VCC, GND), why a bare motor needs a transistor and diode, PWM for strength, and wiring it to ESP32, Pico and Uno.
Community draft — report a mistake
3.3 V or 5 V? On the module, IN only drives a transistor, so a 3.3 V GPIO switches it even with VCC at 5 V. A bare coin motor must never hang straight off a GPIO — it needs more current than a pin can give.
A coin vibration motor is a tiny DC motor with an off-centre weight, sealed in a 10 mm disc — the same part that buzzes in phones. The module adds a transistor, flyback diode and resistor, so your GPIO only supplies a few mA while the motor draws 60–90 mA from VCC.
Use it for silent alerts: wearables, a “your parcel/phone is ready” buzzer, haptic feedback on a button, or a reminder band for someone who can’t hear a beeper. digitalWrite() turns it on and off; analogWrite() (PWM) makes it gentler.
The motor is glued with a sticky pad — stick it firmly to the enclosure wall so the vibration carries. The fine leads break easily; secure them with a dab of hot glue near the motor.
Prices are indicative (Nov 2026) and vary by seller.
Pinout
| Pin | What it does |
|---|---|
IN | Control — HIGH runs the motor; PWM (analogWrite) sets the strength |
VCC | 3.3–5 V supply for the motor |
GND | Ground |
Common errors
Board resets when the motor starts
Start-up current is about twice the running current. Add a 100 µF capacitor across VCC and GND near the motor, or power it from a separate supply with a shared GND.
Weak buzz at low PWM, nothing below a certain value
A small motor needs a minimum voltage to start. Kick it at full power for 50 ms, then drop to the PWM level you want, and keep PWM above about 40 %.
Bare motor wired to a GPIO stopped working
The pin was overloaded or killed by the motor’s voltage spike. Drive bare motors through an NPN transistor (2N2222 / BC547 with 1 kΩ base resistor) with a 1N4148 diode across the motor.