MotorCell is an ultra-compact, shaftless PCB motor designed for high-speed, low-torque applications. With its innovative pancake design and planar PCB windings, MotorCell is perfect for robotics, art installations, and DIY projects. This motor simplifies integration by using sensorless control with PWM speed adjustments.
In this tutorial, we’ll cover:
What is MotorCell?
The MotorCell reimagines motor design by integrating the rotor, stator and driver, into a single, flat PCB. This unique structure:
MotorCell is ideal for applications that require small, lightweight, compact motors, such as small robotics, kinetic art, or even portable gadgets.
Setting Up Your MotorCell
To get started, follow these steps:
Pins:
Open the Arduino IDE, go to Sketch > Include Library > Manage Libraries, search for "MotorCell," and install it. Then include it in your code and setup your pins:
#include "MotorCell.h"
#define IN_PIN 2
#define OUT_PIN 3
#define FR_PIN 1
MotorCell myMotorCell(IN_PIN, OUT_PIN, FR_PIN);
void setup() {
myMotorCell.Init(); // Initialize the MotorCell
}MotorCell Library Functions
Here are the core functions of the MotorCell library:
myMotorCell.Init();uint16_t rpm = myMotorCell.Spin(50); // Spin at 50% speeduint16_t rpm = myMotorCell.SpinPID(12000); // Maintain 12,000 RPMmyMotorCell.ReverseSpin();Pulse(uint8_t p_pin, uint8_t ms_duration): Sends a short pulse to the specified pin for a given duration (in milliseconds). Useful for quick bursts of motion or momentary signals.
myMotorCell.Pulse(FR_PIN, 50); // Sends a 50ms pulse to the FR_PIN
uint16_t currentRPM = myMotorCell.RPMRead();myMotorCell.MaxSpin();Example Project: RPM Monitoring
Here’s a simple project to get you started:
#include "MotorCell.h"
#define IN_PIN 2
#define OUT_PIN 3
#define FR_PIN 4
MotorCell myMotorCell(IN_PIN, OUT_PIN, FR_PIN);
void setup() {
Serial.begin(115200);
myMotorCell.Init();
}
void loop() {
uint16_t rpm = myMotorCell.Spin(50); // Spin at 50% speed
}More examples available on github, but if you have any questions about MotorCell, feel free to contact us!
A PCB motor is an innovative solution that integrates the motor's mechanics into the electronic components, using the PCB itself as the structure of the motor.
What is a PCB Motor?
A PCB motor is a unique type of motor that uses the copper traces on a printed circuit board (PCB) to create a magnetic field that drives the motor. This concept is inspired by how radio systems use PCB traces as antennas. The same principle is applied to generate a magnetic field strong enough to turn a rotor. This type of motor is known as an axial flux brushless motor, where the PCB stator and the rotor are aligned in parallel.
The Design and Construction of a PCB Motor
The first step in creating a PCB motor is designing the PCB stator coils. In traditional motors, these coils are often made from wire wound into dense, three-dimensional shapes. In a PCB motor, the coils are instead manufactured as flat spiral traces printed onto the layers of a PCB.
One of the challenging aspects of these planar motors is fitting enough turns in the small space available to generate sufficient magnetic flux. These coils have to be connected in a star or delta configuration to create a 3-phase system. In our 6-slotted star-configured MotorCell design, we were able to stack the coils on four layers, utilizing two additional layers for the controller, to produce the required magnetic field to spin the rotor.
Over the years, we have also learned that the design of the rotor is crucial for improving the motor's efficiency. It is important to use high-quality ceramic ball bearings and to align the bearings precisely to achieve the optimal mechanical solution. This typically requires specialized tools, so we also offer the MotorCell 's rotor individually, allowing you to easily integrate it with your custom PCB.
Achieving Synchronization in the PCB Motor
One of the most critical aspects of driving a brushless motor is ensuring that the rotor stays in sync with the stator's electromagnetic field. In traditional motors with brushes, synchronization is mechanically managed by the brushes themselves. However, in a three-phase brushless motor like a PCB motor, sensory feedback is necessary to keep the motor running smoothly.
Back EMF is typically used as feedback to control the motor's speed. Back EMF is the voltage generated by the spinning motor itself, which can be measured to determine the rotor’s speed. This information is then fed into the motor’s control electronics, ensuring that the stator coils are driven in sync with the rotor's motion. For the MotorCell, all of this is handled directly by the onboard chip, simplifying the process.
