Generic Calculator Shield for Arduino Photo-journal

[MarkHaysHarris777]

Greetings, well, the physical platform is taking shape. There are several 16x2 (similar) LCD displays to choose from, all well documented on the net. I have chosen the LMB162ABC (Topway) display containing green/yellow backlight LCD, controller, and multiplexer built-in. This is a 5v display, is well supported and can be written to with a standard library (probably the easiest option for most people to build up from, also has the most net support in terms of examples and trouble shooting). As usual there is a hi-res pic behind the thumb pic:



I have chosen to orient the display similar to the C series HP calcs; although, rather than 10x4 keyboard, this prototype will have 7x5, with the [ENTER] key vertical in the third column. Keyboard layouts will be coming later.

Again, this development prototype is designed to have the micro-controller beneath the keyboard back-plane attached via ribbon cable and headers. Optional 3v jumpers will be provided. Initially the 5v supply will come from the micro-controller, but a 7805 or 3v equivalent may be required. Also, contrast pot and optional back light jumper will be provided; full schematic will follow, with keyboard voltage divider and interrupt circuit.

Cheers,
marcus