Help with mini CNC Plotter using old DVD Drives

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1

Hi;

For my after school robotics / electronics club we have decided to have a go at making some CNC plotters using a whole load of old DVD drives that we salvaged from the PC being removed from our school.

The project is based on this Youtube video sadly the follow video has not been made / uploaded so we are a little stuck.

Here is the schematic:

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I am not 100% sure how the whole thing operates (to draw a pic) but looking at the schematic there is no voltage being supplied to the Nano and the only power for the whole circuit seems to come from the USB which will be connected to a PC which I assume will be sending the data for pic.

Does this circuit need an additional power supply?

The circuit only seems to use L293D ICs as the motor drivers, most others I have seen use a motor driver board?

I just want some clarification on what is missing before I plug it into my Macbook and toast £1300 of PC!!

Here is a link to the code files etc:

Thanks in advance for any help

2

Well, since there is no power to the Arduino Nano, I guess it needs an additional power supply. Or connect it to the USB along with the two other chips.

Your PC USB will shut down if too much current is drawn from it. You will have to turn the PC off/on to recover.

Paul

3

Paul_KD7HB:
Well, since there is no power to the Arduino Nano, I guess it needs an additional power supply. Or connect it to the USB along with the two other chips.

Your PC USB will shut down if too much current is drawn from it. You will have to turn the PC off/on to recover.

Paul

Looking at the schematic it looks like the USB port is just there to supply power not a signal. The PC will be connected to the Micro USB on the Arduino and used to send the data for the image that is being drawn? So maybe could I ommit the USB and supply the L293Ds with a power from a battery pack or regulated 5v?

The Nano will be powered by the PC via the Micro USB Port? Or should I tap of 5v regulated for the Nano also?

4

JonnyAlpha:
Looking at the schematic it looks like the USB port is just there to supply power not a signal. The PC will be connected to the Micro USB on the Arduino and used to send the data for the image that is being drawn? So maybe could I ommit the USB and supply the L293Ds with a power from a battery pack or regulated 5v?

The Nano will be powered by the PC via the Micro USB Port? Or should I tap of 5v regulated for the Nano also?

If you are going to use the USB serial connection to the Arduino, just let it power the Arduino and use a separate supply for the stepper motor control. Be sure to connect all grounds together.

Paul

5

Hi JonnyAlpha,
The follow up video for this cnc plotter is available at the following link.

I have built the same machine and it works well for me.

6

Paul_KD7HB:
If you are going to use the USB serial connection to the Arduino, just let it power the Arduino and use a separate supply for the stepper motor control. Be sure to connect all grounds together.

Paul

unless you go about it the super precautious way and have optoisolators on the high side drive, then do not connect all the grounds together. :slight_smile: