CoilCell - Turning it into an Electromagnet

CoilCell can be used as a weak electromagnet, instead of interacting with magnets. By upgrading to the Iron Back-Plate option, you can enhance the 2.5W CoilCell's peak strength to 17 mT, turning it into a weak electromagnet suitable for attracting small metallic objects like paper clips.

⚠ Caution: When using the 2.5W 200-Turns CoilCell, it may heat up to 110°C (especially the iron back-plate). Keep hands away from hot areas to prevent injury and always turn off the coil when not in use.

How It Works

CoilCell operates by passing current through its coil, generating a magnetic field. Instead of controlling polarity to interact with magnets, we can maximize field strength to attract small metallic objects.

Since CoilCell has an integrated H-bridge, it can directly control the coil’s magnetic strength without requiring an external driver. By pulling one of the input pins HIGH, CoilCell will operate at maximum magnetic power. If magnetic field adjustments are needed, the CoilCell library can be used to adjust the power using Pulse Width Modulation (PWM) to finely tune the intensity.

Varying the Magnetic Field Strength

The following example demonstrates how to adjust the strength of the electromagnet:

#include <coilcell.h>

#define COIL_PIN1 2
#define COIL_PIN2 3
CoilCell myCoilCell(COIL_PIN1, COIL_PIN2);

void setup() {
  myCoilCell.Init();
}

void loop() {
  myCoilCell.Drive(true, 100); // Maximum power
  delay(3000);
  
  myCoilCell.Drive(true, 75); // 75% power
  delay(3000);
  
  myCoilCell.Drive(true, 50); // 50% power
  delay(3000);
  
  myCoilCell.Drive(true, 25); // 25% power
  delay(3000);
}

⚠ Note: The Drive() function uses a high-speed PWM timer, making it compatible only with CodeCell and ESP32-based devices.

Understanding the Functions:

Init() → Initializes CoilCell and sets up the control pins.
Drive(bool direction, uint8_t power_percent)
- direction: true (activates electromagnet) / false (not used in this case)
- power_percent: Magnetic force strength (0 to 100%)

Conclusion

This showed us how to power and control a CoilCell and use it as a weak electromagnet, capable of attracting paper clips and other lightweight metal objects. Check out the CoilCell GitHub Repository for more code examples and technical documentation!