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Topic: How to Power Arduino Externally ? (Read 10176 times) previous topic - next topic

Akshaysarraf

I looked a few links, but couldn't understand.

I tried doing it using a Power Adapter from my Old Modem, (I used Adapters of 9V 1A and 12V 500mA)

But It doesn't work. Neither any of the LED is glowing nor my Sketch is Starting.

But it works fine when I try to power it using a USB cable and connecting it to my laptop. What to do ? Please Suggest.

NOTE - I read it in some links, they says to measure the Voltage Readings across Vin and GND Pins of arduino. I don't have any devices to measure Voltage or Current.

I've tried these both adapters... Still not working

(I've Attached Both Images. Please Check)

JimboZA

#1
Dec 20, 2013, 07:37 am Last Edit: Dec 20, 2013, 07:41 am by JimboZA Reason: 1
You need to check that those adapters are "centre positive", assuming you have them plugged into the jack. Look here to see the symbols if you are not familiar with them. Edit: the polarity symbol should be "somewhere" on the adapter- I'm surprised it's not in the view you posted, but it ought to be somewhere.

Do those adapters actually work ?

PS.... you definitely need a multi-meter to do any Arduino work, it's very difficult if not impossible to diagnose problems and check connections otherwise.

Johannesburg hams call me: ZS6JMB on Highveld rep 145.7875 (-600 & 88.5 tone)
Dr Perry Cox: "Help me to help you, help me to help you...."
Your answer may already be here: https://forum.arduino.cc/index.php?topic=384198.0

UnoDueTre

Be very careful with modem power supplies as many of them output AC (at 9 to 12V) as opposed to DC which is what you want.
Look at the supply/adaptor and check for symbols as per the attached pic.

JimboZA

Hmmm good point: one of those pics shows ac-ac, the other is dc.
Johannesburg hams call me: ZS6JMB on Highveld rep 145.7875 (-600 & 88.5 tone)
Dr Perry Cox: "Help me to help you, help me to help you...."
Your answer may already be here: https://forum.arduino.cc/index.php?topic=384198.0

Akshaysarraf

Ok Sir, I'll Buy a Multimeter and will Get back to you.... with My readings.

UnoDueTre

Also look at the polarity on the connector (as JimboZA mentioned).


Akshaysarraf

I Bought a Multimeter and measured the Voltage output of my Adapter. It turns out to be 10.58

Now After Connecting it to my Arduino I Measure the Voltage across GND and Vin it also comes the same.
Still My Arduino doesn't start.

Please Help!!


UnoDueTre

Check on the output of the regulator, it should be around 5V.
Which Arduino do you have?

Akshaysarraf

Voltage across Voltage Regulator is 4.77
I have a Basic Arduino with ATMEGA328 chip. (also known as Arduino Duemilanove, I guess).
Sir, What to do next ?   So that I can turn it ON using my Adapter ?

JimboZA

Sounds to me that if you get the voltage you put in out at Vin, and you're also getting 5v out where you should be, the Arduino is damaged somewhere or other.
Johannesburg hams call me: ZS6JMB on Highveld rep 145.7875 (-600 & 88.5 tone)
Dr Perry Cox: "Help me to help you, help me to help you...."
Your answer may already be here: https://forum.arduino.cc/index.php?topic=384198.0

UnoDueTre

Did you measure the voltage between the regulators output and ground or across the regulator (input and output)?
The correct way is to measure between the regulators output and ground.

Once you have confirmed that the polarity is correct and that you have around 5V on the output of the regulator, then quickly switch on.
I'm not familiar with the Duemilanove, but I'm guessing that it also has a power on led.
Check to see that the led comes on, if it does great, then measure again on the output of the regulator to make sure the voltage has not dropped.

If the led does not come on, immediately disconnect the power.
Either way, please report back.

Akshaysarraf

Earlier I checked across INPUT and OUTPUT of Voltage Regulator. It was 4.77
Now, I Checked across COMMON and OUTPUT it is coming 5.12
And My arduino has a POWER LED, It Turns on when I use My USB Cable along with my LAPTOP to power.

UnoDueTre

OK , those voltages look good.
Have you loaded a simple sketch onto the Arduino like Blink? (this will allow you to quickly determine if it's working with the new power supply).
Now disconnect the USB cable  and try to connect the power supply, looking at the power led and the Blinking led.



Akshaysarraf

Sir, It already had a loaded Sketch, everything runs fine When I Power with USB Cable. But as soon as I Use Power Adapter it doesn't starts. Not Even the Power LED turns on.

UnoDueTre

Try to have the multimeter connected at a point on the power supply and quickly measure as you turn the Arduino on.
Please ensure that you are measuring the output of the power supply.
Report back the voltage that you get.

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