Or a suitable diode can be placed in series between pin D10 and where the 4.7k resistor attaches to the line to the transistor base. If the diode's orientation is correct, it will prevent short circuit of pin D10, when it is set to OUTPUT and HIGH. In this case however, you will only be able to turn the backlight ON with pin D10 in INPUT mode, backlight OFF with pinD10 in OUTPUT mode (either HIGH or LOW). You will have no intensity control.Refer to the following corrected schematic - note that the free end of the diode should have been labeled as connected to Arduino pin D10, rather than labeled with a cryptic BT.
EDIT: ok now i know that there is a version before v1.0, and since mine does not have printed 1.0, I am in doubt....
Did not have time to read the entire thread, but it seems that the schematic can work without changing the hardware. Did anyone already try to not set pin D10 to high (as this would be an issue), but has anyone tried to program the pin as an INPUT with the internal pullup activated? That might draw enough current to close the transistor without blowing up the Arduino pin.
Hello, i've just received this one i don't know why. How can i use it completly with Arduino Uno ?Pictures and programs requested !Thanks a lot my international friendship from Marseille France. Regards Morel Philippe. firstname.lastname@example.org
Just never put pin 10 into OUTPUT mode and you'll be fine.
Hello Eric,Thank you for your inquiry.I've seen this post 2 years ago, but It has been fixed at that time.You could control the backlight with "D10" directly.Best Regards,Grey--DFRobot Tech Support
I think it should have come out to a via, such that if you wanted to you could either solder blob or install a jumper to tie it to whatever pin you want.
That would be nice. But that could add to the board cost, will add to the documentation cost, and might not be appreciated by the target audience who generally seems to want a plug-and-play solution. Setting jumpers or soldering wires runs counter to that expectation.