Pro mini getting very hot / flashing power light

Hi everyone,

I have a board that integrates an arduino pro mini and four LED strips with an ultrasonic range finder. I just made four copies of a board I’ve used for a couple of years now with no problems. I traveled with them (I’m in Brazil where voltage is the same) and am now having issues with 3 of 5 boards. I’ve checked and rechecked the connections but am stumped.

The four LED strips connect to power on the bottom of the board in the images attached and are using MOSFET Transistors. The green wires connect them to the Arduino pins. The other visible wires connect the ultrasonic sensor.

It’s a very simple setup - I removed the power as I thought maybe it needed to be cleaned or something was touching. But I’ve replaced it on all boards and all three are getting extremely hot and the sensor is not working. In one case, one LED strip lit but when I added a second they all went off and the board got hot.

Any suggestions as to possible causes or trouble-shooting steps would be amazing as I’m stumped and am supposed to have four of these working by Friday.

Thank you!
Claudia

Hi,

Can you give us: a) a circuit diagram b) what MOSFETs are you using c) what's your power supply d) what LED's are you using

Yours, TonyWilk

cbernett: Hi everyone,

I have a board that integrates an arduino pro mini and four LED strips with an ultrasonic range finder. I just made four copies of a board I've used for a couple of years now with no problems. I traveled with them (I'm in Brazil where voltage is the same) and am now having issues with 3 of 5 boards. I've checked and rechecked the connections but am stumped.

The four LED strips connect to power on the bottom of the board in the images attached and are using MOSFET Transistors. The green wires connect them to the Arduino pins. The other visible wires connect the ultrasonic sensor.

It's a very simple setup - I removed the power as I thought maybe it needed to be cleaned or something was touching. But I've replaced it on all boards and all three are getting extremely hot and the sensor is not working. In one case, one LED strip lit but when I added a second they all went off and the board got hot.

Any suggestions as to possible causes or trouble-shooting steps would be amazing as I'm stumped and am supposed to have four of these working by Friday.

Thank you! Claudia

Generally when an electronic device is getting HOT is a sign of either drawing to much current for the rated device; or a short.

I would go with the drawing too much current.

How many LED are in the LED strips? What are you using to power these boards?

A wiring diagram would be helpful.

My suggestions are: breadboard the circuit in an actual breadboard to see if the circuit does work. Once you have the circuit working on the breadboard you can then replicate it on the proto perf boards.

If you have new proto perf board build new boards. Go easy on the heat from the soldering iron and the amount of solder.

Which version of the Arduino Pro mini are you using? The 5v version or the 3.3v version?

Thanks for the replies everyone! I made a diagram which I hope will help and is attached but wanted to point out a few things:

– these are replicas of boards I made a few years ago that have been in use with no problems during that time
– I made three copies in New York and then brought them down to Brazil to show the project here
– Upon arrival, I had issues with a couple of the power connectors (thin stranded wire breaking easily) and had to resolder a couple but I believe that even before that a couple of the boards were behaving strangely
– The power voltage standard is typically the same as the US in Rio where I am
– Two of the boards appear to be fine and 3 are not functioning - with the same setup
– A list of all the components are below with links

I continue to be super mystified - I appreciate all your help!

| Breadboard
Adafruit Perma-Proto Half-sized Breadboard PCB -

| Arduino Mini
Arduino Pro Mini 328 - 5V/16MHz

| Ultrasonic Range Finder
Ultrasonic Range Finder - XL-MaxSonar-EZ4

| FTDI Breakout*
for connecting to arduino with USB
SparkFun FTDI Basic Breakout - 5V

|MOSFET Transistors (4)
for regulating the power flow to the LEDs
N-Channel MOSFET 60V 30A

| Female Headers for LED input (8)
Break Away Female Headers - Swiss Machine Pin

| Headers (~30)
Break Away Headers - Straight

| DC Power Jack
– the original I used, using in one board now
DC Barrel Jack Plug - Female

– new one
SIM&NAT DC Female 5.5mmx2.1mm Power Jack Adapter Plug Pigtail Cable, 20inch DC Power Pigtail Female Jack Wire for CCTV Security Camera, DVR, HDVD, LED Strip Light, Low Voltage Application

| Current power adapter
BV-Tech DC12V 1A UL-Listed Switching Power Supply Adapter for CCTV

| LED Strips
Varying - one example:

That is not a diagram, it's a horrid mess.

"in use with no problems" - did you ever put your finger on the voltage regulator?

Just to be clear... what [u]exactly[/u] got hot?

a) In your earlier pictures, it's a bit difficult to see but: Underneath, main power rails, where the power comes in... looks like a short ?

b) You have a 12v supply into the RAW pin of the Pro Mini and you are driving all those LEDs from the +5v output from the Pro Mini ?

If so, it's no wonder: you are frying the tiny regulator on the Arduino board !

Get a 5v power supply.

Yours, TonyWilk

Looks like some solder bridges on the back side power bus, what do you solder with, a red hot horseshoe? :) :) OOPS! I see now, you're using both red & blue lines for - (GND).

Hi, How long are each of the strips? How much current do they draw?

PLEASE draw a circuit diagram ,not a fritzy picture, copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png? Include all your power supplies and all your LED strip connections.

How does your mini pro get power? What do you connect to the DC socket?

Thanks.. Tom... :)

Wow - none of this was helpful. I don't draw circuit diagrams so someone put this together for me. But the intense attitude in the responses is really kind of incredible - never had this kind of response to questions I've posted and I've been doing this a very long time. I'm not a pro in the electronics world but I am a pro in the design and technology world and would have appreciated a bit more respect.

The board you're seeing is a bi of a mess because I am hectically trying to fix it - so I've desoldered a lot. I have looked very closely as all the elements and cannot find a short - though there is a chance I'm missing something. I'm also saying the same things over and over and you're asking questions I've answered, but I'll repeat in case anyone can nicely give me some help at this stage - I do not have time to do a drawing:

-- the power is going into the RAW pin on the Arduino yes. again, it's been that way on other boards for years, zero heat, zero problems. -- my understanding is that 5v is not enough to power LED strips -- the LED strips are about 10" long each

I really believe that this is wired correctly - however, something is causing the ARDUINO to get very hot. Other weird behavior has been:

-- the arduino power light blinks faintly rather than staying on solidly / brightly -- one LED strip going on but is not responding to the sensor, adding a second one turns all of them off

Again - these boards were working find before I traveled. The new type of connector I'm using breaks off easily so I had to resolder the power (hence the mess).

I ask you respectfully to refrain from responding if you're going to be hostile or disrespectful. If anyone else has any other troubleshooting tips for me - thanks in advance.

I would not expect to be able to draw more than 50--100mA from the Vcc pin like this, so when you use LED strips with large current requirements the tiny regulator on the Mini board just gets ultra hot and shuts itself off.

The dissipation in the on-board regulator is (12 - 5) * I, so for even 100mA thats 0.7W, too much for a small SMT regulator.

A separate 5V supply for the LEDs is how to do this, or use a DC-DC converter from your 12V to derive high-current 5V for the LEDs. Perhaps a cheap LM2596 eBay one? They are capable of 2A or so with output voltage selectable by on-board trimmer pot.

cbernett:
It’s a very simple setup - I removed the power as I thought maybe it needed to be cleaned or something was touching. But I’ve replaced it on all boards and all three are getting extremely hot and the sensor is not working. In one case, one LED strip lit but when I added a second they all went off and the board got hot.

Any suggestions as to possible causes or trouble-shooting steps would be amazing as I’m stumped and am supposed to have four of these working by Friday.

Thank you!
Claudia

  • Have you got a DMM, Digital Multi-Meter?
  • Can you put a good board and a bad board side by side and compare pin voltages?
  • If you power up the boards without the LED strips, or the ultra-sonic unit connected, what gets hot?
  • Are you sure your batch of LED strips is 12V?

cbernett:
I don’t draw circuit diagrams so someone put this together for me.

Have you asked the designer, builder to have a look for you?
Why didn’t the designer/builder provide you with a circuit diagram?
You need to have a schematic… Just for this sort of situation.
Thanks… Tom… :slight_smile:

An observation: Your Ultrasonic range finder has a peak current draw of 100mA (during pulse transmit) and this is pushing the limits of the arduino's maximum capability of 150mA (according to sparkfuns website). You should probably feed the sensor directly from the power supply instead :)

https://www.maxbotix.com/documents/XL-MaxSonar-EZ_Datasheet.pdf

MarkT: I would not expect to be able to draw more than 50--100mA from the Vcc pin like this, so when you use LED strips with large current requirements the tiny regulator on the Mini board just gets ultra hot and shuts itself off.

The dissipation in the on-board regulator is (12 - 5) * I, so for even 100mA thats 0.7W, too much for a small SMT regulator.

A separate 5V supply for the LEDs is how to do this, or use a DC-DC converter from your 12V to derive high-current 5V for the LEDs. Perhaps a cheap LM2596 eBay one? They are capable of 2A or so with output voltage selectable by on-board trimmer pot.

In the picture the OP has removed the 12V supply wires that connect to the lower + and - bus along the bottom of the board. The 12V LEDs connect + to the 4 header pins on the 12V bus. The red and black wires are supply for the sonic unit. The green is from the sonic unit. Tom.... :)

cbernett: Wow - none of this was helpful. I don't draw circuit diagrams so someone put this together for me. But the intense attitude in the responses is really kind of incredible - never had this kind of response to questions I've posted and I've been doing this a very long time. I'm not a pro in the electronics world but I am a pro in the design and technology world and would have appreciated a bit more respect.

The board you're seeing is a bi of a mess because I am hectically trying to fix it - so I've desoldered a lot. I have looked very closely as all the elements and cannot find a short - though there is a chance I'm missing something. I'm also saying the same things over and over and you're asking questions I've answered, but I'll repeat in case anyone can nicely give me some help at this stage - I do not have time to do a drawing:

-- the power is going into the RAW pin on the Arduino yes. again, it's been that way on other boards for years, zero heat, zero problems. -- my understanding is that 5v is not enough to power LED strips -- the LED strips are about 10" long each

I really believe that this is wired correctly - however, something is causing the ARDUINO to get very hot. Other weird behavior has been:

-- the arduino power light blinks faintly rather than staying on solidly / brightly -- one LED strip going on but is not responding to the sensor, adding a second one turns all of them off

Again - these boards were working find before I traveled. The new type of connector I'm using breaks off easily so I had to resolder the power (hence the mess).

I ask you respectfully to refrain from responding if you're going to be hostile or disrespectful. If anyone else has any other troubleshooting tips for me - thanks in advance.

Concerning doing this a long time. On the Arduino forum you have posted 3 times using the current login. If this forum is not meeting your requirements and/or needs, why not post to the previous forums where you sought help?

Okay, The drawing is showing RGB LED strips and the amazon.com link to LED strips is to a 12V white LED with Power 12V and Ground. Which one is correct. 10 inches of LED strip is how many LED? Need to know how many LED to know how many amps are required.

A scan of a pencil drawing on paper would have been better than the fritz diagram. a photograph of a pencil drawing on paper would have been better than the fritz diagram.

When you post further links please use the url tags.

Just because something has worked for years does not mean that it will continue to work for years. stuff wears out. The fact it worked on other boards before does not imply that it will work on these boards.

Concerning the diagram. The MOSFETs and LED Strips should have their own power supply separate from the Arduino Power Supply. The only connection between the MOSFETs and the Arduino should be the PWM pin to the MOSFET.This will keep the current going through the Arduino to a minimum. Tie the grounds together.

Do you have a way to test the LED strips without the Arduino or MOSFETS? This does depend on what type the LED strips are, RGB or White Only.

Do you have a way to test the UltraSonic Sensor?

When you say that the Arduino is hot, can you tell which part on the Arduino Board is hot? Have you access to the cans of spray for cooling electrical parts? Normally, I used these to find the discrete transistor which had gone into thermal runaway.

Knowing which part is becoming hot would provide information that would help solve the mystery.

These Arduino Boards that you are using, are these clones or are they original Arduino Pro mini boards?

I do have to ask. Why all the de-soldering and re-soldering when you did not know that was the issue?

Have you replicated the circuit on a breadboard and not the proto perf board?

a suggestion, get a pack of the multi-color breadboard wires. it makes troubleshooting much easier. I like the silicon insulated wires. The silicon wires are nice to work with.

cbernett: Hi everyone,

I have a board that integrates an arduino pro mini and four LED strips with an ultrasonic range finder. I just made four copies of a board I've used for a couple of years now with no problems. I traveled with them (I'm in Brazil where voltage is the same) and am now having issues with 3 of 5 boards. I've checked and rechecked the connections but am stumped.

It's a very simple setup - I removed the power as I thought maybe it needed to be cleaned or something was touching. But I've replaced it on all boards and all three are getting extremely hot and the sensor is not working. In one case, one LED strip lit but when I added a second they all went off and the board got hot.

Thank you! Claudia

I need to ask for a clarification. Which board is getting hot? I have been reading your posts that the Arduino board has been getting hot, but you could also mean that the proto perf board is getting hot.

Thanks everyone - these are helpful tips. Given the timeframe, I'm going to have to circle back to all of this when I'm back in the country where I can buy parts and have time. It's hard to describe the context I'm in but I'm both without resources and time.

I remain surprised that people think the basics are incorrect - but I will definitely read through the suggestions and take a look. As I said, 2 of the exact same setup are working fine, don't get hot, do the right thing. I've left them plugged in for a day or two without problems. This suggests to me that something is out of wack or got dislodged in travel on the broken boards but I will do a thorough review.

Also good to know about the diagram - with more time I am able to do it. A few responses to comments:

-- had to desolder because the power connector broke off. then it wasn't working so I was trying to clean it up and nove it to a different spot - but I've said this. -- I don't post often on this forum but have many times in the past under an old login - again, why the challenge to my status? This is now how this kind of community once behaved when I was more active in it. -- The Arduino ITSELF is getting hot -- I am the designer and builder but have a colleague helping me to make the boards - again, we had 4 new boards working perfectly before I traveled -- These are not old boards, they re brand new based on the old model so nothing has worn out

cbernett: Thanks everyone - these are helpful tips. Given the timeframe, I'm going to have to circle back to all of this when I'm back in the country where I can buy parts and have time. It's hard to describe the context I'm in but I'm both without resources and time.

I remain surprised that people think the basics are incorrect - but I will definitely read through the suggestions and take a look. As I said, 2 of the exact same setup are working fine, don't get hot, do the right thing. I've left them plugged in for a day or two without problems. This suggests to me that something is out of wack or got dislodged in travel on the broken boards but I will do a thorough review.

Also good to know about the diagram - with more time I am able to do it. A few responses to comments:

-- had to desolder because the power connector broke off. then it wasn't working so I was trying to clean it up and nove it to a different spot - but I've said this. -- I don't post often on this forum but have many times in the past under an old login - again, why the challenge to my status? This is now how this kind of community once behaved when I was more active in it. -- The Arduino ITSELF is getting hot -- I am the designer and builder but have a colleague helping me to make the boards - again, we had 4 new boards working perfectly before I traveled -- These are not old boards, they re brand new based on the old model so nothing has worn out

Okay, How were the boards packed for travel? Assuming you traveled by commercial airplane where were the boards located during the flight? How long was the flight?

good before travel and bad after travel points to the travel being the culprit.

That would imply that either solder joint have broken or the proto perf board has micro cracks or the Arduino boards have micro cracks or broken solder joints.

depending on where the boards were in the airplane they may have been subjected to temperature extremes.

were the boards subject to x-ray during the travel?

were the boards subjected to any static electricity? Static Electricity can blow chips in a blink of an eye.

Ahhh - this was by far the most helpful tip, this must be it! Like I said, I have 2 perfectly working boards. They produce no heat and function properly. Lesson learned for future to pack them better as it must be it!

Hi, Do you have a DMM to cross check a good and faulty board?

Can I suggest any future boards, you put a row of headers where the controller fits into the board, that way you can unplug and interchange controllers, and pre-test your boards before fitting the controller.

Tom.. :)

cbernett: Ahhh - this was by far the most helpful tip, this must be it! Like I said, I have 2 perfectly working boards. They produce no heat and function properly. Lesson learned for future to pack them better as it must be it!

You failed to answer my questions.

Why do you ignore questions?