0

Arduino Uno possible issue
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Arduino Uno possible issue

by cgray9 on Wed Jun 26, 2013 7:14 pm

I just got my arduino uno starter kit in and was following the book, and it seems like the pins 5,6, and 7 wont hardly light up an LED, I checked the voltages coming out and they are about 5V but the currents are nearly non existent. I know the circuit i set up works because when all i do is change the power wire to pin 3 or 4 the LED shines nice and bright. Is this supposed to be like this or is there something wrong with the board?
cgray9
 
Posts: 3
Joined: Wed Jun 26, 2013 7:11 pm

Re: Arduino Uno possible issue

by adafruit_support_bill on Thu Jun 27, 2013 6:22 am

Be sure to set the pinMode to OUTPUT. Otherwise it will default to INPUT. When in INPUT mode, a digitalWrite HIGH just enables the internal pullup resistor and it will not source significant current.
http://arduino.cc/en/Reference/pinMode

adafruit_support_bill
 
Posts: 81608
Joined: Sat Feb 07, 2009 10:11 am

Re: Arduino Uno possible issue

by cgray9 on Thu Jun 27, 2013 6:37 am

I did make sure that they were on HIGH, when it's on HIGH it is only outputting about 0.2mA instead of the 13mA the working pins are outputting, also the voltage is only about 4.6V on the pins that aren't working while the voltage from the working ones is reading about 4.96V.
cgray9
 
Posts: 3
Joined: Wed Jun 26, 2013 7:11 pm

Re: Arduino Uno possible issue

by adafruit_support_bill on Thu Jun 27, 2013 7:17 am

I did make sure that they were on HIGH

But did you make sure they were in OUTPUT mode? You need to call pinMode to set the pin mode to OUTPUT.
http://arduino.cc/en/Reference/pinMode

adafruit_support_bill
 
Posts: 81608
Joined: Sat Feb 07, 2009 10:11 am

Re: Arduino Uno possible issue

by cgray9 on Thu Jun 27, 2013 3:22 pm

It was the output issue, when I read the reply early this morning I was thinking it was the HIGH or LOW, and i just kinda assumed since i was getting some voltage and current it was set as output. Thank you.
cgray9
 
Posts: 3
Joined: Wed Jun 26, 2013 7:11 pm

Please be positive and constructive with your questions and comments.