Hi all, this is my first post here, and my second day with Arduino and with electronics, so I’m really a beginner, also not a native english speaker (let me know if something doesn’t make any sense).
I tried to do my best to share my thoughts and ask the correct questions, but I’m sure I made some huge mistakes, please excuse me.
This is my “Hello World” project, I have:
- An Arduino Due
- A biploar stepper motor from a DVD driver
- An Easy Driver stepper motor driver (v4.2)
- A TowerPro 9g micro servo (SG90)
- An old ATX PSU (Enermax Liberty ELT500AWT 500W)
- A chunk of jumper cable, a breadboard, lots of free time and big plans
I’d like to control the stepper motor and the servo via USB. The program is working (basic SerialPort buffer writing with C#), everything looks good, but I’m afraid I’ll fry something because of the different voltages.
I read that I should not use the 5V pin on Arduino because the Due based on 3.3V. Since I didn’t want to use batteries or multiple DC adapters for different voltages, I transformed my old ATX PSU to a DIY lab power supply unit. It has all the required voltages (3.3V, 5V, 12V). With this solution I don’t need to use any power pin or VIN on Arduino, only the digital ports and the GND (magic smoke stays inside the chip hopefully).
The micro servo uses 5V, and the EasyDriver uses 12V. I simply wired all the different voltages and the ground to a breadboard and I try to use the optimal one for each component. This is how it looks like currently:
As you can see the Arduino, the Easy Driver and the micro servo all wired to this breadboard, one-by-one. It is working, however for some reason if i don’t plug in the 12V power input into the breadboard (so the only available voltage is the 5V for the servo) the power LEDs are still turned-on on the Arduino and on the Easy Driver. It looks like the Arduino tries to do it’s job with the only 5V which comes from the servo (this is just an uneducated guess). The stepper motor is struggling to rotate, the power LEDs are very pale, so it doesn’t look good. Also if I plug-in the 12V and 5V together (as you can see on the image), the Easy Driver’s chip getting hotter with time (I can touch it for about 20 sec but I can’t measure it). Is it somehow adds together, and makes 5V+12V?!
I’m not sure what’s the problem here. Can I use different voltages with common ground like I do it on that image? is there a chance that my solution fries something? Am I using the common ground correctly? I’m lost here.
Also, I’m not even sure which GND (on the Arduino) should/must be plugged in to the common ground. All of them? Some of them? Is it depending on the power load?
One last thing, I’m not sure if my approach with the ATX PSU is a good idea. What do you think?