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Topic: Analog ports disturbed (Read 3104 times) previous topic - next topic

dc42

The wiring of the pot in the photo looks correct to me, assuming it is a normal pot with the wiper being the middle connection.
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afremont

#16
Mar 15, 2013, 01:06 am Last Edit: Mar 15, 2013, 01:09 am by afremont Reason: 1

The wiring of the pot in the photo looks correct to me, assuming it is a normal pot with the wiper being the middle connection.


Ok I'm blind, I magnified it and now I can see that the orange wiper wire extends beyond the power bus and into A1.  What about the red wire on the outer tab of the pot?  It "appears" to be connected to an empty bus strip I think.  Also I see a ground wire connecting the bottom negative bus to the top one, but I don't see a positive wire extending to the bottom bus.
Experience, it's what you get when you were expecting something else.

olimex

I found the problem. When I store a value from analogRead and then use it in analogWrite, all the other analog ports gets disturbed.

Do you have the same problem?

dc42

If analogWrite interferes with analogRead, this normally means that you have a common ground wire serving your input and output devices, and a dodgy connection in that ground wire.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

olimex

Yes you are right!!! Thank you so much!!!

But What should I do to solve the problem?

Grumpy_Mike

Make the contact secure soldering wires is a good idea.
Or route the grounds separately so they converge at one point on the arduino ground.

olimex

Now all the GNDs are converging at one pin next to the 5v, are you saying that i should wire them that the pmw Ground ends at the GND next to digital pins?  :smiley-fat:

dc42

Best is to use 2 ground pins on the Arduino. Use one to connect the ground side of your analog input devices (the pot, the temp sensor and the voltage divider). Use the other one to connect the ground side of your ourput devices (TIP121 and associated 12V supply), and power to the Arduino if it is not coming from USB.

Did you add that resistor in series with the TIP121 base?
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

olimex

Now i'm at school, when I get back home i will let you now!
:smiley-mr-green:
Yes i added it! Excuse me ignorance, but why Arduino needs it?

Grumpy_Mike

Quote
but why Arduino needs it?

To limit the base current to a safe level.

olimex

My Arduino burned up... I am literally crying. After one year and an half of service. I tried to upload blink sketch and it works but after a while the atmega328 starts to heat... I'am so sad  =(

retrolefty


My Arduino burned up... I am literally crying. After one year and an half of service. I tried to upload blink sketch and it works but after a while the atmega328 starts to heat... I'am so sad  =(


Well for about $5-6 you board can enjoy another year and half of service, that's pretty cheap entertainment.

Maybe you weren't storing your board away in a ESD bag or using a grounded wrist strap.  ;)

Lefty

dc42

Have you disconnected everything from the Arduino except the USB, and checked that nothing is shorting the underside of the circuit board?

If yes and the atmega328p is still heating up, then probably all you need to do to get it working again is purchase a new atmega328p-pu with bootloader already installed.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

olimex

I Will try! But the sketch Works! Maybe the Voltage regulator that doesn't pushes correct Voltage to to atmega?

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