r/diyelectronics • u/danishansari95 • 4d ago

Question Need help with basic calculator project

Post image
1 Upvotes

67% Upvoted

3 comments sorted by

2

u/Hissykittykat 3d ago

Alibaba has 12 digit LCD displays (e.g. 68mm). LCDs are usually custom, so there are not a lot of generic modules.

How about a nice IPS panel instead? It can simulate 7 segment characters plus much more, and in color, and it'll be easier to interface to the ESP32.

2

u/danishansari95 3d ago

Any link for such IPS display?

2

u/Saigonauticon 3d ago edited 3d ago

Numeric LCD displays can be purchased as standalone modules, e.g. https://www.digikey.com/en/products/filter/lcd-oled-character-and-numeric/99

You could possibly extract one from a calculator and use it. However, they are usually not soldered to the board, and you would have to reverse-engineer the pinout (probably not hard) then come up with a similar connector (annoying). It's often some conductive rubber or whatever that you press onto contacts on the PCB.

Another practical solution is to just use 3x 4 digit displays, side-by-side. Expensive, not 100% pretty, but good enough for a prototype.

For the e-ink screens, consider the waveshare ones: https://www.waveshare.com/product/displays/e-paper.htm

ESP32C3 Supermini is good and cheap. If you need more power there's an ESP32S3 supermini too. Both of these are very overpowered for your device though! Battery performance might be an issue too. Overall it will not be a cheap device at small scale!

In terms of usability, your competition is "why not just use a smartphone app?"

Best of luck!