My ground is burning the arduino out!

Hello,

When i connect my arduino and teensy together with the rx and tx everything goes fine but when i connect my ground from the teensy to the arduino my regulator burns out… If tried it twice and same result.

My setup is as following:

Arduino on the VIN and GND 12v and 0v
Teensy on the VIN and GND 5v and 0v

The power supplies i use are from Mean Well. 5v 7A and 12v 10A.

Im realy stuck with my project right now and im out of options. Or should i tie both grounds directly together?!

Thanks,

Nena

Here’s the OP’s attachment (so I don’t have to download it):

ce0b76ffbd65fba663c49566a5df4c44956860f7.jpg
Note to OP: If you want to know how to embed an image, check this out: How To Embed An Image

And, check this out, too: http://forum.arduino.cc/index.php?topic=149015.0

So you know why I don’t have nearly enough information to even begin to help you.

For instance…when you say “my regulator”…what regulator? The regulator on the Arduino? The regulator on the Teensy? The regulator on your Iron Man suit?!? I suppose the photo implies it’s the Arduino regulator – on third look, I noticed the little dark spec on the regulator chip – but that could be a number of things.

Also, Rx Tx between the Arduino and the Teensy? If so, then how was that working without the grounds connected together?

And, a schematic of your setup would help immeasurably!

Much mystery in your post! ;D

Please post a complete, hand drawn wiring diagram showing ALL the connections, including all those that might be to the household AC wiring.

I hope this will do.


Nena

Need to know the connections to the AC lines as well.

Ground/Neutral/Earth potentials can vary between different branches of the AC line (called "ground loops") and can be large enough to destroy equipment.

The ac lines are going to a central point, also the Earths of the ac.

Thanks,

Nena

Time to get out your multimeter and figure out what is burning up Arduinos!

ReverseEMF:
For instance...when you say "my regulator"...what regulator? The regulator on the Arduino? The regulator on the Teensy? The regulator on your Iron Man suit?!? I suppose the photo implies it's the Arduino regulator -- on third look, I noticed the little dark spec on the regulator chip -- but that could be a number of things.

Also, Rx Tx between the Arduino and the Teensy? If so, then how was that working without the grounds connected together?

And, a schematic of your setup would help immeasurably!

Much mystery in your post! ;D

Hahaha :slight_smile:

Sorry, its about the arduino. If i connect the rx and the tx from the Teensy to the rx and tx from the arduino there's not a problem. But when i connect the ground from the teensy to the arduino, the arduino's regulator (5v) burns out. The arduino runs on a 12v power supply and the teensy on a 5 volt power supply.

Yes the dark spot is the burnout of the arduino's regulator :slight_smile: When i only connect the rx and tx nothing burns :stuck_out_tongue:

Thanks,

Nena

Sorry, its about the arduino.

No, it is about the "ground connections".

Arduinos do not burn up when properly connected.

jremington:
No, it is about the "ground connections".

Arduinos do not burn up when properly connected.

She means: her statement regarding the "regulator, that burns out", is all about the Arduino [not the Teensy, or her Iron Woman suit :wink:

Suggestion: Connect both power supply grounds together, then from that connection point, feed all the other grounds. In other words. 5V supply ground connects to 12V supply ground. And, at the point where those two are connected, run a line to the Teensy ground, and another line to the Arduino ground, and do this for any other ground. Essentially, a star pattern.

This may not solve your grounding problem, but you're less likely to destroy your Arduino, or your Teensy. This is the way all power connections should be done. You need to think in terms of "wires as resistors". Everything has resistance. And at the kinds of currents present in power connections, even wires can behave like resistors -- i.e. develop voltages across them. And where you have voltages, you have the potential for current flow--currents that might flow where you don't want them to flow, like the wrong way through regulators, and stuff.

Now, regarding the underlying problem: as jremington pointed out, there's likely some sort of ground loop involved. And, if so, there will, probably, be some sort of odd current running through those power supply ground connections. The star pattern will merely prevent this current from flowing into and through your devices, but the source of the current probably needs to be addressed. I'll defer to someone else for that diagnosis, as that's not my strong point!

Hello,

I tried to disconnect all other grounds at the arduino even all other items that where running at the 12v so only the arduino was connected. But i blowed out a third arduino... one left :slight_smile: mmmzz...

Cant i use the 5 volt from the teensy to power the arduino?!

Im realy out of options. If it was a ground loop it should be stopped by disconnecting all the grounds?!

3 arduino's dead in a few hours :slight_smile: not that fun... i need to order new ones...

Thanks,

Nena

What dosn't add up to me is all that very neat wiring and kit but it goes with so little understanding of the basics of electricity.

What I would do is to disconnect everything from the power supplies and start with a clean slate. Then wire just the two V- outputs of the two power supplies, call this the ground. Then take a meter and measure the voltage from this ground to the V+ of each supply. It should measure only 5V and 12V.

Next measure from this ground point to the ground points in your circuit, do not connect the circuits up just where the ground points should be. Include the earth in that. You should not see any large voltages. Put the meter on AC and measure again. If you do see any large voltages then I would suspect earth leakage problems in your power supplies. We have had several people here that have had trouble with Mean Well power supplies. Almost as if the name tells it all, they Mean Well but fail to produce a decent supply.

Remember never connect things up with the power on, that is a sure way to burn things out.

Are you sure 'ground' is the problem.

Isn't a Teensy 3.3volt logic.
Connecting 5volt TX/RX/GND from the Uno means that the Uno is phantom-powering the Teensy through it's protection diodes. And an Uno can't supply more than 100mA if you power it with 12volt. It will overheat.

Maybe you should drop the idea of using the TX/RX pins, and use I2C to communicate between them.
Leo..

Edit: the Uno will be much happier if you power it with 5volt on the 5volt pin or, better, on the USB socket. That also bypasses the 5volt regulator, so you can use your burned Arduinos.

Hi Wawa,

Ya, ill try that, using the 5v where also the teensy is hanging on. Tested my 5v and it is 5.02v so should work.

Greets,

Nena

Still have the problem that there is that 5volt on the TX/RX lines of an Uno all the time.
Connecting 5volt to the TX/RX pins of a Teensy might fry the Teensy.
No experience in Teensies though.

I2C is an open collector bus, and much more suited to join devices with different logic voltages.
Leo…

I think i found the arduino killer :slight_smile: when measuring i found out that the 2 buttons IN where measuring -3 volts. Without connecting the teensy or something else. Probably a ground loop as mentioned by you guys!

Im going to look at it further...

Ill try to use the INPUT_PULLUP of the uno to connect it otherwise mayby this will solve my problem.

Nena

Edit:

Can it be that the cabel is making too much resistance that the pullup resister is not seen anymore as a damping but as a divider resistor, the cables are atleast 2 meters long so the travel distance is 4 meters. Just a thougth.

Ill try to use the INPUT_PULLUP of the uno to connect it otherwise mayby this will solve my problem.

Sorry no it won’t. It is nothing to do with pull up resistors, solve it at source. What are these buttons connected to?

Can it be that the cabel is making too much resistance that the pullup resister is not seen anymore as a damping but as a divider resistor, the cables are atleast 2 meters long so the travel distance is 4 meters

No, the resistance of two meters of wire is negligible compared to a pull up resistor.

If that voltage on the buttons is AC pick up then use a 1K pull up resistor and a 0.1uFceramic capacitor to ground. Also put a diode cathode to input anode to ground to chop off any negitave voltages.

However all that would not point to blowing a hole in a regulator.

After you find out what’s blowing up the Unos, you still have the issue that the Teensy 3.6 I/O is not 5V tolerant. A TXB0104 might be simple solution although I really want ask... what is the Teensy doing? I don’t see any I/O connected. That’s a lot of computing power for a serial connection.

Hi Guys,

Found the arduino killer! The +5v was probably shorten by the earth connection... I took a photo from the connections and made a new connection and sealed the earth. (is not needed there) (as you can see at the background!)

Thanks a lot!

WattsThat:
After you find out what’s blowing up the Unos, you still have the issue that the Teensy 3.6 I/O is not 5V tolerant. A TXB0104 might be simple solution although I really want ask... what is the Teensy doing? I don’t see any I/O connected. That’s a lot of computing power for a serial connection.

It worked fine with testing and let it run for seven days without problems, ill keep in mind that TXB brakeout! Thanks!

Uhm, there are only two rx/tx used now but there are 20 switches that need to be connected and 2 audio sensors and all the communications from the network are going to the teensy and from the teensy to the arduino.

EDIT:

It did the trick! IT WORKS :slight_smile: