Why do I keep blowing my Arduino?

tunacheese · August 18, 2018, 5:37pm

I'm using a BTS7960B with an Arduino. The Arduino is powered using a PP3. The BTS7960B has it's 5v input from the Arduino's 5v supply, and then I have a 12v SLA battery connected to the power input of the BTS7960B to power a motor.

I've blown 3 Arduinos now so I am clearly doing something wrong. The first one didn't blow for a few minutes and I was able to use the motor as expected, and then it blew. The second two blew as soon as I started connecting the SLA to the B-/+ of the BTS7960B.

What am I doing wrong?

LarryD · August 18, 2018, 5:48pm

Show us a good schematic of your circuit.
Show us a good image of your wiring.
Give links to components.

Posting images:

tunacheese · August 18, 2018, 6:14pm

sorry - here is how its hooked up

DrDiettrich · August 18, 2018, 6:29pm

A circuit diagram is something different. Where's the data sheet of the board?

I cannot see a PP3 (what's that?) and no voltage regulator on the board, so I only can assume that you fry the Arduino from the 12V battery input.

el_supremo · August 18, 2018, 7:05pm

The PP3 is a 9V battery.
That is not going to last long when powering an Arduino UNO. You need a proper DC supply.

Pete

Robin2 · August 18, 2018, 7:13pm

We need to see the datasheet for the motor driver board.

A PP3 battery won't last long but it should not be the cause of damage to the Arduino.

What exactly happened to the Arduino board when it "blew"?

I wonder if the wires to the Arduino GND and 5v pin are incorrect?

...R

tunacheese · August 18, 2018, 8:08pm

The PP3 (9v battery) is only being used temporally. I do plan on having the 12v SLA battery supply power to the Arduino and also the motor.

Robin2:
What exactly happened to the Arduino board when it "blew"?

I wonder if the wires to the Arduino GND and 5v pin are incorrect?

...R

The first time, it all ran for a few minutes, and I was able to use the motor. The 2nd and third time, as soon as I connected the SLA battery to the motor, there was a spark on the battery terminals, and the Arduino gave out a puff of smoke.

Not sure what to do now, as it's wired the same as the examples I have found online.

el_supremo · August 18, 2018, 8:35pm

the Arduino gave out a puff of smoke

That suggests that the 12V from the SLA was connected directly to one or more of the Arduino pins.

Pete

jremington · August 18, 2018, 9:04pm

I do plan on having the 12v SLA battery supply power to the Arduino

This is a bad idea if you plan to power more than 1-2 LEDs from the Arduino pins, as the internal regulator will overheat.

Use a separate step down regulator to supply either 7-9V to the RAW input, or 5V to Vcc.

srnet · August 18, 2018, 10:55pm

tunacheese:
sorry - here is how its hooked up

You sure about that ?

Where is the Arduino UNO getting its power from ?

PieterP · August 18, 2018, 11:50pm

Looks like this driver: https://artofcircuits.com/product/btn7960b-43a-h-bridge-motor-driver-module

The inductive load of the motor might produce some high-voltage spikes on the supply that could kill the regulator of the Arduino.

Pieter

Robin2 · August 19, 2018, 7:43am

tunacheese:
and the Arduino gave out a puff of smoke.

I was hoping you would tell us which part on your Uno board emitted the puff of smoke? Can you post a photo of the damaged board that shows the damage?

And are you using a genuine Uno or a clone?

...R

TomGeorge · August 19, 2018, 8:59am

tunacheese:
The PP3 (9v battery) is only being used temporally. I do plan on having the 12v SLA battery supply power to the Arduino and also the motor.

The first time, it all ran for a few minutes, and I was able to use the motor. The 2nd and third time, as soon as I connected the SLA battery to the motor, there was a spark on the battery terminals, and the Arduino gave out a puff of smoke.

Not sure what to do now, as it's wired the same as the examples I have found online.

Sounds like you have fried the motor driver.
Connect the battery to the driver with the UNO completely disconnected.
Does it spark?
Where is the fuse for the 12V battery, that SLA is capable of providing more then 50A in a burst if needed.
What is the spec/data of the motor?
Can you post a picture of your project so we can see your component layout please?
Thanks.. Tom...

tunacheese · August 19, 2018, 7:32pm

jremington:
This is a bad idea if you plan to power more than 1-2 LEDs from the Arduino pins, as the internal regulator will overheat.

Use a separate step down regulator to supply either 7-9V to the RAW input, or 5V to Vcc.

Oh. It was my understanding the DC in can take between 6-12v? Is the issue that a fully charged 12v SLA will read around 13v?

srnet:
You sure about that ?

Where is the Arduino UNO getting its power from ?

sorry - as per my initial post. It's being powered from a separate 9v PP3 battery.

PieterP:
Looks like this driver: https://artofcircuits.com/product/btn7960b-43a-h-bridge-motor-driver-module

The inductive load of the motor might produce some high-voltage spikes on the supply that could kill the regulator of the Arduino.

Pieter

But the Arduino has it's own power supply? (9v PP3 battery)

Robin2:
I was hoping you would tell us which part on your Uno board emitted the puff of smoke? Can you post a photo of the damaged board that shows the damage?

And are you using a genuine Uno or a clone?

...R

Ah - not sure where exactly the smoke came from. But the board doesn't seem to show any signs of damage. The board is an Elegoo UNO R3.

TomGeorge:
Sounds like you have fried the motor driver.
Connect the battery to the driver with the UNO completely disconnected.
Does it spark?
Where is the fuse for the 12V battery, that SLA is capable of providing more then 50A in a burst if needed.
What is the spec/data of the motor?
Can you post a picture of your project so we can see your component layout please?
Thanks.. Tom...

Well the Arduino is definately blown too as it no longer connects via USB. The lights don't come on and I can no longer upload to it. Adding power to the motor driver produces no sparks, but I am unable to see if it still works as I have no working Arduinos left (I have ordered some more though). I didn't have a fuse connecting to the battery - but will make sure to for the next build.

tunacheese · August 19, 2018, 7:42pm

Updated diagram

TomGeorge · August 19, 2018, 9:36pm

Hi,
With the battery connected and no UNO connected.

Measure the voltage across the Vcc and gnd pins that would usually connect to the UNO 5V and gnd.

Then measure the voltage between the gnd and each of the two input pins that would usually be connected to the UNO.

Thanks.. Tom...

tunacheese · August 20, 2018, 9:04am

TomGeorge:
Hi,
With the battery connected and no UNO connected.

Measure the voltage across the Vcc and gnd pins that would usually connect to the UNO 5V and gnd.

Then measure the voltage between the gnd and each of the two input pins that would usually be connected to the UNO.

Thanks.. Tom...

Will do when I get home from work. I should be expecting them all to read 0v, right? as the 5v for the Vcc and the PWM inputs comes from the UNO.

MarkT · August 20, 2018, 12:13pm

Is the 5V terminal on the motor driver board an output or an input? If its 5V output, connecting it
to the Arduno 5V would indeed risk frying it.

Experiment first with a multimeter and just the motor driver powered up without motor. What voltages
appear on the 5V and arduino signal pins?

Then power down, connect motor, power it up again and recheck - you can select the input

Then only if the 5V on the driver isn’t outputing 5V, can you consider connecting it to the Arduino
5V (after powering everything down).

I believe you should always apply motor power before Arduino power with motor drivers that take a 5V input, since most
of then will try to power the motor from the Arduino’s 5V in that circumstance and overload it
(not sure about this particular driver - read all the data carefully).

system · May 5, 2021, 6:39pm