Loss of USB connection Autosteer Module

Good morning all,

I come to you today because I very often lose the usb connection. I installed a small relay on PWM2 in order to cut the voltage in the Phidgets when the guidance is disabled. I noticed that the loss of USB connection happens when I deactivate the guidance.

Here is my current montage:
-BNO055 installed
-RTK on
-AOG v4.1.12
-I cut the red wire of my USB cable to avoid double powering of the Arduino

Thanks in advance for your feedback

Have a good day,

Was it a new problem after adding the relay?

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Hi Brian,
Before installing the relay I had 1 or 2 connection losses during the day but since I installed it is rather every 10 minutes. But I absolutely need this relay because it allows me to cut the voltage in the Phidgets so that I can turn around.
I specify that I have the Cytron md13s powered by 12V

When a relay is turned off, it creates a fly back voltage. This causes electrical disturbances in your electrical system. The easiest way to get rid of this is to hook up a diode backwards on the relay coil as close to the relay coil as possible. Here is a good illustration of why it happens and why the relay fixes it (TLDR):

Are you using good single point grounding technique? All ground coming to the same place and then a heavy wire to the battery. Also a heavy wire wire from the positive to a single point that then stars out to all the connections. Make sure no other grounds like GPS, or the antenna touch the chassis, but all those ground come back to a single point.

Noise induced in the power supply lines will cause usb to lock up


What area of wire is recommanded ? 1.5mm² (AWG15) ? Or 1.31mm² (AWG16) or 1mm² (AWG17) is enough ?



The size wire is based on the load (amp draw) and length of wire. I would use one of these charts to get started:

I typically go with one size heavier than calculated, for peace of mind.

I’ve used 1,5mm2 or 2,5mm2.

I use 2.5mm2 from the battery to the AutoSteer box, and all other power lines use 1.5mm2.

I power the laptop from the AutoSteer box as well.

Yes at least 2mm.

2.5mm2… Not easy to root inside the box throught the screw terminal bloc. I use 1.5mm2 wire for all power line and 1,5mm2 is already not very flexible and not easy to insert in the terminal du to the space between the terminals (Battery in and the 2 ground terminals).
For the Cytron terminals, 1.5mm2 is already a little to big of it.

Ok I will try 2.5mm2 from battery to PCB Batterie in.


you can terminate the heavy wire in a convenient spot, and then run thinner wires to your parts. Be sure to fuse the positive right at the battery post

Hi @ThomasM
May I ask how you connected that relay, cause I would like to make the same setup so it would be easier to turn the steering wheel when not engaged. Can you describe the pin out for a newbie like me?

Make sure your tablet or pc USB port device manager setting is set so it does not allow powering off the device.

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Hi @MortenP
My relay is connected to PWM2-5v-GND on the coil side. Then on the engine output of the cytron

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Hello @bduncan
Can you explain to me how to make this setting on Windows 10? Sorry for the late reply i have a lot of work right now

Start the Windows Device manager, click the arrow next to universal serial port controllers, find the hub and serial device that is used to connect to your arduino, and then right click, properties, click the power management tab, and then remove the check to allow the computer to power the device down.
My computer would shut off the hub, and the usb-serial adapter that receives the NMEA signals.

Hi again @ThomasM
What kind of relay are you using? I’m not sure I understand you correctly, what do you mean by PWM2-5v-GND?

Hello! Please help! In the video I will show you the problem! If the mot goes and I charge the tablet the usb ports disappear, why is that?

It looks like you have everything powered from one place.
And maybe power is off from that output, in the moment where you start engine.
So arduino is shortly off, and does not reconnect correctly.
I suggest power directly from battery (with fuse off course)