Data logger can function without a display, but I realized that having one will make it much more understandable and easier to use. I shopped around for small graphic LCD with white backlight and black text. What I got was Zolen ZLE12864A LCD module from eBay seller in China. Although units with these exact colors were not listed after some discussion I got what I was looking for. Seller was able to look up exact LCD module for me with 3.3V logic level voltage. There is decent datasheet with setup commands and dimensional drawing as well. It has ST7565P controller – although cheap it does not have any font memory built it. Size of PCB will most likely define size of data logger.

It did take some months to arrive as I did not pay for express shipping. Manufacturing looks very clean and nice. First impression of LCD itself was not so great, though. Regardless of tweaking it has some vertical and horizontal shadows around displayed text and appearance changes a bit depending on viewing angle. But after a while I got used to it. If they look somewhat cheap that’s because they are. I got five for just $6 per item. They will be good enough for initial data logger prototypes. Main bottleneck might be code space and memory needed to operate them.