Reverse polarity applied to Vin

Using Arduino General Electronics
1

Hello

I made mistake with cable polarity while connecting 10,4V battery to Vin of my UNO :frowning:
The boards' 5V regulator fired up...
I had an LCD Keypad shield and a Big Easy Driver connected to the board. Could they also be damaged, or the UNO's board is somehow protecting them?

Kindly,
Artur

2

You tell us. I wouldn't count on anything being OK, but it is possible.

Don't worry, we've all done that, several times each! Chalk it up to experience.

3

I will :slight_smile:
I'm placing an order now, just not sure whether I should buy only board, or the whole setup :confused:

4

You can always test the components individually, but even if they seem to work, the test is not conclusive. They may eventually fail spectacularly.

5

Ok. Thanks for reply

I've just order the UNO and will test this out ::slight_smile:

Anyway... If I burned up everything, then I'll give up with my project for some time (it's my first time with arduino and electronics) :confused:
I spent HOURS prototyping, testing and troubleshooting. Another hours packing, wiring and soldering everything in a tiny box :roll_eyes: Everything was ready and working flawlessly 8) Then the final part - a cable with DC jack which I thought I knew polarity - boom $#@&! :sob:

6

I have done this enough times that I ALWAYS keep a multimeter handy, just to be absolutely sure that both the voltage and the voltage polarity are what they should be, before plugging in the power connector.

Down the road you will also forget that 3.3V modules usually fry when plugged into 5V power supplies or connected to 5V output pins.

7

Sh*t happens. :frowning:

.

8

The DC socket is polarity protected with a 1Amp diode between DC socket and V-in.
10.4volt on V-in is borderline for the onboard 5volt regulator when it has to power an LCD shield and other things (getting too hot). The DC socket drops 0.7volt, so is a better choice.
Leo..

9

Thanks for reply.

@Wawa, good information, thanks :slight_smile:
I don't have enough space in my enclosure to keep the DC socket, I have to unsolder it. But I think I can solder wires/pins in place of DC socket instead of using Vin/GND pins

Kindly,
Artur.

10

philip100:
Thanks for reply.

@Wawa, good information, thanks :slight_smile:
I don't have enough space in my enclosure to keep the DC socket, I have to unsolder it. But I think I can solder wires/pins in place of DC socket instead of using Vin/GND pins

Kindly,
Artur.

Why are you using an Uno instead of a Nano or Pro Mini if you're short on space?

11

Well... You just nailed me :frowning: I don't know, perhaps lack of knowledge in electronics :confused:
My project is based on an OpenBuilds tutorial. I replicated each step blindly focusing on portability.

I managed to fit this in a 90x65x32mm enclosure

2372×869 128 KB

You got me thinking of new design :slight_smile:

Kindly,
Artur.

12

Nano is, for most purposes, a direct replacement for the Uno - same pin numbering, etc, just on a smaller PCB. It uses a purpose-built USB-serial interface chip, instead of the 16u2, but hardly anyone reprograms the 16u2, so this isn't usually an issue.

13

I already ordered a new UNO, so I'll test out what I have.
But anyway, you got me thinking of even getting rid of the display and use bluetooth module and control it with a phone. All the electronics would fit next to the stepper motor and I could use smaller ganrty plate 8)

Thanks,
Artur.

14

Here is my opinion.. you may not like it.

If you don't have enough space to "do it right", you have already done it wrong. So start over.