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Spining BLDC(Gimbal) motors at super slooooooow speeds with Arduino and L6234

First of all You won’t find here any information on high speed BLDC motor driving. For that purpose You need to know rotor’s position, so You have to measure back-EMF or use Hall sensors (not needed here).

Spining BLDC(Gimbal) motors at super slooooooow speeds with Arduino and L6234

For basic info about driving BLDC motors here is best “classic” articles on internets:
Driving a three-phase brushless DC motor with Arduino – Part 1. Theory

Driving a three-phase brushless DC motor with Arduino – Part 2. Circuit and Software

http://www.instructables.com/id/BLDC-Motor-Control-with-Arduino-salvaged-HD-motor/

I used specialized triple half bridge IC L6234 (~ 8$). You can make the same spending less money (but more time) with MOSFET transistors or other IC.

But be careful, I found a lot of cases in various forums, where people burned their Arduinos or L6234 chips.

I also very recommend to study (or/and purchase) this open hardware driver board based on L6234 BLDC Motor Driver by Michael Anton. It has input protecting resistors, zeners, power supply/filtering components and even back-EMF sensing circuit with amplifier (not used here).


L6234 datasheet is surprisingly useless. Go straight to Application Note AN1088 instead.

My setup of Arduino and DIY driver-board

I added current limiting resistors (1kΩ) to all INputs and ENable pins, a bunch of capacitors recommended in application note and current sensing shunt resistor 0.6Ω (big blue one).

There is main illustration, for basic BLDC driving using 6 step sequence(rectangular current):

Schematic Spining BLDC(Gimbal) motors at super slooooooow speeds with Arduino and L6234

It works very well on high speeds. But on slow RPM’s You will have choppy steps. So we need to smooth out driving current to sine waves:

For More Details: Spining BLDC(Gimbal) motors at super slooooooow speeds with Arduino and L6234

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