Unstable code/arduino on DC wall-power?

Post here about your Arduino projects, get help - for Adafruit customers!

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
kramerica
 
Posts: 36
Joined: Thu Oct 08, 2009 6:43 pm

Unstable code/arduino on DC wall-power?

Post by kramerica »

Scenario: Arduino Duemilanove - with a program on it.
When connected to USB cable - it runs for days... (not sure how long it will run, but I have seen it run for 3+ days without issue)
If I remove the USB cable and plug in my adafruit 9V regulated DC wall-power adapter , the arduino powers up and runs for less than 10 hours and then I see 'crazy characters' on the LCD, and the arduino appears unresponsive.
I do not have both USB and DC connected at the same time.
I can post to code later if you think its helpful.
I only have a few things hooked to the arduino.
1.) a speaker + 2 LEDs - for notification and output state.
2.) a PIR sensor - to track motion
3.) an i2c - with a 16x2 LCD on SPI communication - to display information
4.) a reed sensor (old 2 wire security contact switch) - to track drum position.
5.) a powerswitch tail - to activate a small AC motor.

There doesn't appear to be a jumper or anything on the arduino that would tell it USB power or DC power - the documentation says that it auto determines it.

Power
The Arduino Duemilanove can be powered via the USB connection or with an external power supply. The power source is selected automatically.
External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector.
The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.

User avatar
liudr
 
Posts: 121
Joined: Sat Jan 15, 2011 11:08 pm

Re: Unstable code/arduino on DC wall-power?

Post by liudr »

How much current is the wall adapter rated? Have you tried another wall adapter yet?

User avatar
kramerica
 
Posts: 36
Joined: Thu Oct 08, 2009 6:43 pm

Re: Unstable code/arduino on DC wall-power?

Post by kramerica »

The module is: 9V up to 660mA of current draw.

I noticed the power cord was touching the wires going into the LCD - so I moved it away, and I was still getting scrambled characters on the LCD after about 12 hours?

I also had the LCD - in a Breadboard / with the I2c backpack in the breadboard. (each had male headers) I removed the breadboard completely... and it's been running since Friday night without issue? (over 48 hours)

User avatar
adafruit_support_bill
 
Posts: 88093
Joined: Sat Feb 07, 2009 10:11 am

Re: Unstable code/arduino on DC wall-power?

Post by adafruit_support_bill »

660mA should be more than enough. Sounds like it might have been a marginal connection in the breadboard. Not sure why it would care about how it was powered - unless maybe the marginal connection was where the power supply was patched in.

User avatar
jl-p
 
Posts: 1
Joined: Wed Aug 08, 2012 6:35 am

Re: Unstable code/arduino on DC wall-power?

Post by jl-p »

Hi kramerica.

Did you fixed the issue. because i have the same. if i use a usb wall plug my stable lab power suply or any other adapter my ultrasonic sensors are unstable.
with usb connected to my laptop / computer or tv. everything is perfect.

Kind regards

Johan

Locked
Please be positive and constructive with your questions and comments.

Return to “Arduino”