Hello,
I happened to have a similar LCD lying around, so decided to give it a try. I am only using the third and fourth segment though, as I do not have a 74HC595, and limited pins on the Arduino Uno.
It seems to work fine, and I'm planning to use this to display sensor output (e.g. temperature) in the future.
I have some questions on the transistor part though:
- Are the PNP transistors wired up correctly?
In fact, in this case, the transistors seem overkill; I did some current measurements, and current out of LCD pins 1 and 2 never seemed to exceed 15mA. It seems to work fine without transistors as well. Any feedback appreciated. - Is it necessary to put an additional resistor between the Arduino pins (12 and 13) and the PNP transistor bases? According to Arduino Forum, I should. Again, in this case it seems overkill, as the currents I measured at the base were in the order of 1mA.
Attached a Fritzing schematic and the full code.
Any feedback would be greatly appreciated!
LCDv2.ino (2.88 KB)
