When it does not buzz
The LED is the first clue. It lights whenever the MOSFET conducts, from the same 3.3 V as the motor, but its current does not pass through the motor. So a dark LED with SIGNAL HIGH is power or wiring, and a lit LED with a still motor is the motor or its leads. Six symptoms cover nearly everything.
Six symptoms
Pick what the block is doing. The ringed part of the board is where to look, and the sentence under it is the check to make.
Still, and the LED dark
Nothing on the block is happening. The LED needs the 3.3 V rail, which needs
VCC, and it needs the MOSFET closed, which needs SIGNAL HIGH and a shared
GND. So it is one of three wires. Count from the square pad: GND, VCC, NC,
SIGNAL. Then check that MOTOR_PIN names the pin SIGNAL is really on.
The LED lights, the motor does not
Everything up to the motor worked: the rail is there and the switch closed. The LED's current goes around the motor, not through it, so the motor or its two thin leads are the fault. Look at the pads on the right where the red and blue leads are soldered.
Weak, or low levels do nothing
A weak buzz is usually a board lying loose, so most of the shake goes into
lifting it off the desk: fix the board to what it should shake. VCC on 3V3
is not the cause. The motor gets about 3.3 V from 3V3 as from 5V, measured
on a board. A low analogWrite level that does nothing from rest is the
motor's starting voltage, 2.3 V, about 178 of 255: a kick to
start is the fix.
It runs when it should not, or the board resets
The 10 kΩ keeps the motor off whenever nothing drives SIGNAL, so a motor that runs by itself is being told to: the pin is HIGH at boot on that board, or the sketch writes HIGH early. Use the pins this book uses.
A board that resets as the motor starts is short of current. The motor asks for up to 120 mA as it starts, and from a 3V3 pin that comes out of your board's own regulator. Move VCC to 5V, or VBUS on a Pico, where the block's regulator takes it.
When it does not work
Wire GND and VCC only, then touch a jumper from SIGNAL to your board's 3V3 or 5V. The LED should light and the motor buzz; take the jumper away and both stop. If they do, the block works and the problem is the pin or the sketch.
The strapping pins read at reset (0, 2, 5, 12 and 15) and the flash pins (6 to 11). A strapping pin can sit HIGH while the board boots and buzz the motor before your sketch runs. GPIO 4 avoids both.
Check the supply first: a battery that is running down, or VCC on 3V3 from a board that is doing a lot else. The motor's datasheet puts it through 86,400 on and off cycles in its life test, so a new one wearing out in an afternoon is unlikely.
The likely ways are mechanical: a lead pulled off its pad, or the motor peeled off its tape and hanging by its leads. Electrically the block is hard to hurt from SIGNAL, which only reaches a gate rated for 12 V. VCC beyond the regulator's 8 V would be the other way.
The pins, the supply and the wiring on one page, for when you only need to look something up.
The Vibration Motor reference page →Edit this page — content/books/vibration-motor/when-it-does-not-buzz.mdx
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