I just decided to take the plunge and get started with arduino so this post will be riddled with newbie-ness. Last week I received an Arduino UNO R3, a basic LCD (https://www.sparkfun.com/products/9054
), and some other stuff to play with including temp/humidity sensor and barometric pressure sensor. I tried a few of the basic sketches, then felt confident enough to play with the LCD. "Hello World" worked just fine and I played with a few others. I hooked up the temp/humidity sensor (DHT22) and that worked easily and perfectly. I've had it outputting to the LCD with no problems. I added the barometric pressure sensor (BMP085, from Adafruit) and got that working too.
I decided to switch from USB power to a 9v battery. It was fine at first, but when I picked it up (arduino, battery, and breadboard) the text became garbled -- output to serial still worked fine and the sensor data was ok. I assumed I shorted something by picking it up, but i can't find where. I used some canned air on it, but it didn't help. I disassembled/re-assembled with no sensors and I can't get the standard "Hello World" sketch to work.
The text is a mix of english, japanese, and symbols. the counter can be seen , but in the wrong place, by 12 seconds, the LCD blanks for a while, but then turns back on with different characters. Of note, the text did change a little after using the canned air so i suspect that helped. But i have no clue what i did. i've been searching high and low since last night and haven't found anything that helped. ANy ideas would be great.