Materials Required

• DC - Geared Motor^[1]
• Neodymium magnets^[2]
• Transistor IRLIZ44N^[3]
• custom made 3D Structure
• Diode

Geared DC Motor

DC - Geared Motor

The DC Geared Motor we use is a combination of 4:4:1 gears and a brushed DC motor. The motor is cylindrical, with a diameter just under 25 mm, D shaped output shaft which is 4 mm in diameter and extends 12.5 mm from the face plate of the gear box. This motor unit weighing 95 g, has a speed of 1400 RPM and 150 mA Current rating at 6V.

3D Structure with magnets

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Magnets and 3D structure

Neodymium cubic supermagnets of size 5 mm are fitted into a 3D structure on the motor, to create a magnetic field for the fish inside the bioreactor. The 3D structure is a platform to be fitted on the DC motor, having cubical holes to fit the magnets in.

Geared DC Motor

Transistor IRLIZ44N

It is a single pulse avalanche rated MOSFET in an isolated package. It has a continuous Drain current of maximum 30 A and Drain to Source maximum withstandable voltage of 16V.

Circuit

The circuit uses a Transistor and a Diode to control the RPM value using a PWM pin from Arduino.

Circuit Diagram for Stirrer Control

Assembly Video

Files

The files for the 3D structure can be found here : Aachen_Stirrer.zip

The files for the Debug program can eb found here : Aachen_StirrerDebug.zip

References

1. ↑ https://www.pololu.com/product/1570/specs
2. ↑ http://supermagnete.de/eng/supermagnete-strong-neodymium-magnets
3. ↑ http://www.irf.com/product-info/datasheets/data/irfz44n.pdf