Using a USB->TTL (USB to Serial) Device, without exploding my PC

Hi Everyone,

Hope this is the right board for this.

I’ve just acquired a USB 2.0 to TTL UART 6PIN CP2102 Module Serial Converter and wanted to check if there’s anything I need to do to ensure I don’t damage my PC.

I intend to use the power output from the converter to power my device.

Which is basically an Atmega chip, a couple of shift registers, an LED 7 Segment display, a few LEDs and a Micro Servo. Is that a Good Idea?

Could I damage something if I try and draw too much current? How do I check?

Can link to the specific device if it helps… don’t want my first post to be a product link!

Thanks in Advance.

Jeff.

Usually USB-ports are protected against over-current draw, but don’t count on it.

The only thing i think could be a problem is the servo - in practice i have run small servos from USB-supply with no problems.

I am using Apple-computers and on those i get a dialog up on the screen when i draw too much current or directly short the supply - nothing breaks. I’ve only seen permanently broken USB-ports on early computers with USB-ports - modern computers employ polyfuses on the ports. In some cases re-plugging the device enables the port again, and in some rare cases you need to restart the computer.

// Per.

JeffSergeant: Which is basically an Atmega chip, a couple of shift registers, an LED 7 Segment display, a few LEDs and a Micro Servo. Is that a Good Idea?

All sounds fine except the servo. A servo can draw a lot of current in bursts.

JeffSergeant: Could I damage something if I try and draw too much current?

Most PC's have decent protection but some don't. Most desktops let you pull more current then laptops. So a desktop will probably drive one servo just fine but there is no guarantee.

JeffSergeant: How do I check?

Measure the current. And to get closer to the peak current of the servo, measure it will stalling the servo (or at least give it a decent load).

But for the servo it's probably better to get an external supply. Simplest supply for that, a USB charger.

JeffSergeant: Can link to the specific device if it helps..

Of course it helps!

JeffSergeant: don't want my first post to be a product link!

Why not?

Thanks, I'll try a separate power supply for the servo, and once I've built the thing I'll check the current under load.

septillion: Why not?

If I was writing an automated spam filter, it's the sort of thing that would get people blacklisted!

It's one of these: https://www.amazon.co.uk/gp/product/B00AFRXKFU/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

JeffSergeant: If I was writing an automated spam filter, it's the sort of thing that would get people blacklisted!

Then write a better spam filter :p Most spam posts are not long. Or implement captcha, email validation etc.

JeffSergeant: It's one of these: https://www.amazon.co.uk/gp/product/B00AFRXKFU/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

That's one of the devices you use, what about the rest? ;) That's just a usb-serial interface. The 5V on that comes just straight from the USB port. The chip does absolutely nothing with it. It's a different story for the 3,3V thou.

The rest doesn't exist outside my head yet!