Laptop Freezes/Lags when powering BTS7960 (DIY FFB Steering Wheel Project)

[alanmjdd]

Hi everyone,

I am currently building a DIY Force Feedback Steering Wheel and I’ve run into a major issue where my laptop starts lagging and stuttering heavily as soon as I turn on the power supply for the motor.

Here is my hardware setup:

• Microcontroller: Arduino Leonardo

• Motor Driver: BTS7960

• Motor: RS 550 DC Motor

• Encoder: 600 PPR Rotary Encoder

• Power Supply: 12V 20A

• Software: EMC Lite

The Problem:

When I connect the Arduino via USB (without the external 12V PSU turned on), everything works fine. The software detects the board and the encoder reads correctly.

However, the moment I switch on the 12V 20A PSU to power the BTS7960 driver, my laptop immediately becomes unstable. The mouse cursor freezes/stutters, and the operating system becomes very laggy. If I turn off the PSU, the laptop returns to normal instantly.

What I suspect:

I suspect this is a Ground Loop or heavy EMI (Electromagnetic Interference) noise feeding back into the laptop through the USB cable.

Questions:

1. Has anyone experienced this specific lag with the BTS7960 and Arduino Leonardo?

2. What is the best way to isolate the noise? Would adding ferrite beads or capacitors to the motor terminals help?

3. Is a USB Isolator necessary in this case?

Any advice or wiring tips would be greatly appreciated.

Thanks!

[xfpd]

Show your wiring diagram.

[alanmjdd]

[xfpd]

Put the Leonardo on its own power supply, and ensure the ground is shared with the other power supply.

[TomGeorge]

Hi, @alanmjdd
Welcome to the forum.

Can you post some images of your project?
So we can see your component layout.

Can you please post your code, using code tags?

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[jremington]

@alanmjdd

Any advice or wiring tips would be greatly appreciated.

Avoid ground level problems and ground loops by making sure that the laptop and the PSU are powered from the same branch of the household AC circuit, or better, run the laptop and/or the motor from batteries.

[gilshultz]

An annotated schematic would be a big help. It may be a wiring fault based on the fact when the 12V power is turned on you have problems. I have assumed the motor was not on at that point. Also a clear picture would be a big help. The BTS7960 has an internal connection to the from the motor power - to the logic -. I cannot follow your wiring diagram as some of the lines disappear. I have used many of these modules with great success. Note the wire gauge you are using for the motor and motor.