From my first Digi-Key searches on segmented LCD displays, I couldn’t really find LCD displays less than $10 with as many segments as I wanted, i.e. around 10 segments. Likewise, I found out that LED displays ran around similar costs, $5 for 4 digits. But, now I search again, and the magic is in opening up the search criteria. Sure, I can’t find a 7-segment LCD display with as many digits as I like at the price point I want, but I found a 14-segment display with 8 digits and about $4 for one unit.
20191203/https://www.digikey.com/product-detail/en/lumex-opto-components-inc/LCD-S401C39TR/67-1792-ND/469781
And, circling back to modifying my previous expectations, I also found a good 4-digit, 7-segment LCD display, about $4 for one unit.
20191203/https://www.digikey.com/product-detail/en/varitronix/VIM-878-DP-RC-S-LV/153-1115-ND/1118605
The good news is that both of these display modules come in through-hole mounting. The bad news? Well, again, LCD displays are more complicated to drive than LED displays, but why exactly is that? It’s not just a question of multiplexed or individual segment drive. It’s also that LCD displays require an “alternating current” oscillating square waveform to drive, and if a DC voltage is applied, that will cause irreversible damage to the display. That means you can’t miss a beat if you are driving an LCD display directly via a Raspberry Pi. For an Arduino microcontroller, although this is easier to guarantee even if you are directly connecting to GPIO pins, one wrong programming move and you’ve damaged your LCD display.
Here is some good information I’ve found on how to drive an LCD display. Of course these search results are all very old as nothing has really changed in this field in decades. As it turns out, the reason why there is a preference for direct segment drive on simple low segment count LCD displays is that multiplexed LCD display drive is even more complicated than is the case with multiplexed LED displays.
20191203/DuckDuckGo how to drive segmented lcd display
20191203/https://forum.arduino.cc/index.php?topic=51464.0
20191203/https://web.archive.org/web/20070317082006/http://ww1.microchip.com/downloads/en/AppNotes/00658a.pdf
20191203/https://web.archive.org/web/20110914140715/http://www.atmel.com/dyn/resources/prod_documents/doc8103.pdf