Smoke from the motor shield

as TomGeorge says

Everything runs on smoke, let the smoke out, it stops running....

One of the (very knowledgeable) contributors on this site has a signature that states that everything runs on smoke - let the smoke out and it all stops working. Was he right?

That tongue in cheek comment aside, you need to post (a hand-drawn) circuit diagram of your setup - now what it should be, but what it really is.

If your PC no longer recognises the Arduino Mega (when powered via the USB) you may have a terminal condition with that device. Measure the voltage when connected to the USB at the 5.5V and 3.3 V pins - are they what you expect?

EDIT - Gawdang beaten to the punchline by TomGeorge!

The motor shield has two power inputs. The first is for the logic circuits and must be 5V. The second is the power for the motor and can be higher. But if you connect both to 12V you will put 12V on the logic pins of both the shield and the Arduino pin and yes this will destroy both.

Here is the schematic diagram

Initially, the circuit looks like this:

I connect both SCL and SDA to the Arduino. But the motor driver didn't work until I connected 5V and GND of the Arduino to the motor driver(even tho the motor driver was powered by 12V plug and I dont know why I must connect 5V and Gnd between the driver and the arduino). At this time, I powered up my mega using PC and my motor driver using plug

Then, I dont want my mega to be connected to the PC and want test my power supply to supply both of the Arduino and the shield. Because I am doing a project where both of the motor driver and my Arduino mega will be powered up by a better, so this is just for testing purposes. Here is the schemetic diagram after I connected the power supply to both of the motor driver and the arduino.

I connect the 12V plug cable to the screw terminal connector of the motor driver. Then I connect a jumper from that same screw terminal to the Vin and GND for Arduino Mega.

No diagrams! Read the how to use this forum sticky post for how to post pictures.

You need to connect the power and ground to the motor shield so you can send control signals to it. You need also to supply power at a higher voltage to the motor.

Really sorry..there was something wrong with the link that I copied..now I have edited the post :smiley:

Thank you so much

You show a 5v connection between the motor shield and the board.

Post the details of your motor shield (link).

That 5v i suspect is an output from the motor board, have you measured the voltage on it.

In your second diagram the + supply is connected to ground on the mega and the - supply is connected to another ground on the mega.

You have probably blown a ground track off the mega.

HellenT:
I connect the 12V plug cable to the screw terminal connector of the motor driver. Then I connect a jumper from that same screw terminal to the Vin and GND for Arduino Mega.

That is not what your diagram shows.

If by Vin of the Mega you mean the barrel connector then you have the jack supplying 5 v to the mega and also the motor board supplying 5v to the mega also, bad idea.

Sorry

There was an error with the 2nd diagram. Here is the updated one

And here is my motor driver.

I haven't measure the voltage yet from the 5V output of the motor board. But when I connect 5V of mega and 5V of shiled together according to the first diagram, the board will not power on if i didn't connect the shield to the PC

HellenT:
I haven't measure the voltage yet from the 5V output of the motor board. But when I connect 5V of mega and 5V of shiled together according to the first diagram, the board will not power on if i didn't connect the shield to the PC

The adafruit stack shield FAQ says that only the motor board OR the arduino should be powered.

Documentation is poor.

You need to check if there is 5 V output by the motor board when it is powered up.

I have had problems with clone motor boards before with specifically this problem.

I read about that but i thought that is only applicable if the board is attached to the Arduino. But i didn't attached the Arduino and the board together

But you did connect the 5 v lines

So how should I connect the shield and the Arduino?

and how do I supply current to both of them?

I think we need to know something about the motor. Motors and shields are not "one size fits all". How about linking the motor vendor so we can look up the specs ?

Hey guys I think I've done the same thing my Adifruit motor shield was stacked on the v3 Uno
I by mistake put 12vlts on the wrong terminal block thought because the driver had two motors it used two separate power connections so just connected to anyone lol. After the smoke the Arduino would not communicate correctly and time out uploading library's. So then I thought will that Uno is dead so I grabbed by other one lol put motor Shield on uploaded my library connected my motor put my 12vlts on correct terminal block this time all was good until putting power jumper on more smoke and another dead uno this time Unknown USB device error . I'm guessing my motor shield that seems to be OK is actually not and now frying everything it connects too. Now all my boards are dead is there any way to fix the Uno by replacing the big chip or is she toasted for good

Everythingistoastsorry

Mydakota:
Now all my boards are dead is there any way to fix the Uno by replacing the big chip or is she toasted for good

What is damaged right now is definitely uncertain. Impossible to tell what's busted right now. If there's a lot of time on our hands.... then could start with replacing regulators.... or try to remember what was smoking, and replace that. Otherwise, to save time - just buy a heap more uno's - and next time just make sure everything is compatible (in advance). It's always tempting to just plug something in ..... and hope for the best. But certainly there can be the consequences to deal with later on if we didn't check on compatibility.

One problem I see is that there should be no 5V connection between the Mega and shield because both have their own regulators.

Ralph_S_Bacon:
One of the (very knowledgeable) contributors on this site has a signature that states that everything runs on smoke - let the smoke out and it all stops working. Was he right?

You forgot the occasional shrapnel let loose in all directions from abused electrolytic caps.

The circuit may have released all of it's magic smoke and stopped working, but the caps are still out for revenge.

:slight_smile:

Mydakota:
Hey guys I think I've done the same thing my Adifruit motor shield was stacked on the v3 Uno
I by mistake put 12vlts on the wrong terminal block thought because the driver had two motors it used two separate power connections so just connected to anyone lol. After the smoke the Arduino would not communicate correctly

I once plugged a USB cable inside my computer into the IEEE 1394 header by accident. The magic smoke escaped from my "multi-card reader" and I had to buy a new one. ** :(**

(I also made a red colored dummy for the 1394 header and made a small sticker with an arrow that says "<--- NOT USB")

all was good until putting power jumper on more smoke

Never ever alter the wiring when a circuit is powered up. This is a universal rule in electronics.