Send only data through USB-TTL Converter no power

Projects General Guidance
1

HI,

I'm new to using Arduino and I need help with my project, I am using an Arduino Nano to control an electric wheelchair (it mimics the function of the joystick controller) but I need to send the commands through cabled serial communication. My Arduino is powered using the motors present in the wheelchair but it also needs to be connected to a PC. When I introduce any extra voltage to the Arduino, the signals that are used to control the wheelchair are not the correct ones. And when I use the Mini USB port present in the Arduino Nano, the PC adds extra voltage.

At first I was working with a bluetooth HC-06 module with my Arduino Nano (the module was paired to the PC). I was using Bluetooth because it doesnt sent extra voltage to the Arduino. The schematic I used is number 1 in the image I uploaded.

But I have issues with Bluetooth, so I want to have a wired connection to my PC, but I also dont want to introduce extra voltage. So I was thinking of using a 2102 USB-TTL converter to connect it directly to my PC using the serial pins and I was thinking of using the schematic that is in Number 2 of the image I uploaded.

201074659_988134885296338_7332713136997030665_n
201074659_988134885296338_7332713136997030665_n2048×1536 240 KB

My question is: Can I use the second schematic or will connecting it that way introduce more voltage to my Arduino.

Thanks for any help, and sorry if this is in the wrong category, first time user forum user here.

2

Please read the first topic telling how to get the best from this forum.
Your post lacks almost everything needed to help You.

3

Thanks ill add the right information.

4

just don't connect the USB-TTL Vcc line.

5

This worked for me, thanks.

6

That sounds very strange!

Exactly what do you mean?