Calculator

Final Devlog Before Approval

Calculator

Calculator running on CircuitPython firmware with a Feather RP2040 with DVI output, driven by a 5x4 matrix keypad.

Hardware

• Adafruit Feather RP2040 DVI
• 5x4 matrix keypad, diodes pointing toward the columns (cathode at column, anode at row)
• HDMI/DVI display — tested target is a 7” 1024x600 panel, driven at 800x480 (panel scales it down)

Keymap

x      ^      √      ÷
7      8      9      X
4      5      6      -
1      2      3      +
clear  0      .      sum

(√ and ÷ show as the real symbols on-screen via the custom font which a extraction of the baisic one to preserve memory)

Usage

Basic math — type a number, an operator, another number, then sum to evaluate. Chained expressions evaluate left to right
x as a variable

• x 3 sum → stores 3 into x (the screen shows x=3)
• x + 5 sum → substitutes the stored value of x into the expression
• Pressing x with nothing stored yet and using it in a calc shows an x undef error
  √ (root) — binary, first number is the degree, second is the radicand: 2 √ 9 sum → 3 (square root of 9). 3 √ 27 sum → cube root of 27.

clear

• single press → clears the current entry/expression only
• triple press within ~0.6s → also wipes the stored x value (shows mem cleared)

Case

I dint yet make the display part of the case as im planning to do tht after i get it (I did Make the hinge part tho as i needed to get the 15 mins to post this devlog)

Finished up the repo and ready for shipping !!!

finished code

Finished the pcb and designed the keypad half of the case il prolly design the display case after getting it

Finished the schematic and nearly dun w the pcb ish

Made a keymap and started making the pcb schematic

Uhm research and made a sorta BOM and i hve a sorta idea on how to proceed planning on running it on a lipoly battery and w a display w a dvi in