I have a circuit with a DH22 sensor, DS18b20 and an LCD screen (I can provide a wiring schematic if needed). Both are digital. My power supply is a switching 9v 1amp.
My problem is that when the Arduino first starts the display works fine. After some hours it starts to display random characters. I think the screen is still getting written to since the characters do change. EDIT I happened to be looking at the monitor and it seems like one of the LCD write statements writes garbage then one by one the other ones fail.
If the LCD screen is showing garbage and I hook the Arduino up to my laptop it shows the correct values on the serial monitor. I also noticed that when I did this the LCD started showing the correct characters again. EDIT Seems like the Arduino just reset when I opened the serial monitor.
Based on what I found on here and Google it seems like it is a noise issue. I tried the following:
Adding .1 uf ceramic capacitor in parallel on both power inputs for the LCD and on each sensor
Twisting power wire together
Any suggestions?
I can make a circuit diagram if needed (if needed can you recommend a site or software to draw one?).
conniemac:
I have a circuit with a DH22 sensor, DS18b20 and an LCD screen (I can provide a wiring schematic if needed).
Always!
conniemac:
Both are digital. My power supply is a switching 9v 1amp.
Both what are digital? You should not power the Arduino via "Vin" or the "barrel jack" for serious projects as the on-board regulator is unable to supply much current; if you have a proper (regulated) switching power supply at 5 V, such as a "phone charger", use that to power the Arduino via the USB jack or the "5V" terminal.
conniemac:
My problem is that when the Arduino first starts the display works fine. After some hours it starts to display random characters. I think the screen is still getting written to since the characters do change. EDIT I happened to be looking at the monitor and it seems like one of the LCD write statements writes garbage then one by one the other ones fail.
Sounds like overheating of the regulator.
conniemac:
If the LCD screen is showing garbage and I hook the Arduino up to my laptop it shows the correct values on the serial monitor. I also noticed that when I did this the LCD started showing the correct characters again.
Sounds like overheating of the regulator. You have not explained what LCD you are using. The backlight may be drawing so much current that the regulator overheats and shuts down. See above re supplying power.
conniemac: EDIT Seems like the Arduino just reset when I opened the serial monitor.
That's how it works.
conniemac:
I can make a circuit diagram if needed (if needed can you recommend a site or software to draw one?).
I have used www.circuitlab.com - it is not too tedious. Some use "Fritzing" but people here object to having the "layout" pictures posted, an actual schematic is OK.