Forth Calculator

• https://hackaday.io/contest/195949-2024-business-card-contest
• https://hackaday.com/2024/05/07/the-2024-business-card-challenge-starts-now/
• roughly 3.5 in (90 mm) by 2 in (50 mm).

Rows are input ports with pull up resistors and interrupts, columns are open drain output ports.

    C0       C1       C2       C3       C4
+--------+--------+--------+--------+--------+
| Pi     | 1/x    | x^2    | LOG    | LN     |
|        | y^x    | SQRT   | 10^x   | e^x    |  R0
| A      | B      | C      | D      | E      |
| 0x20   | 0x21 ! | 0x22 " | 0x23 # | 0x24 $ |
+--------+--------+--------+--------+--------+
| STOx   | RCLx   | SIN    | COS    | TAN    |
| CEIL   | FLOOR  | ASIN   | ACOS   | ATAN   |  R1
|        |        | SL     | SR     | F      |
| 0x25 % | 0x26 & | 0x27 ' | 0x28 ( | 0x29 ) |
+--------+--------+--------+--------+--------+
| ENTER  | SWAP   | NEG    | EXP    | BS     |
| DROP   | ROT    | ABS    | F>S    | CLx    |  R2
|        |        |        | S>F    |        |
| 0x2A * | 0x2B + | 0x2C , | 0x2D _ | 0x2E . |
+--------+--------+--------+--------+--------+
| CLOCK  | 7      | 8      | 9      | /      |
|        | FLOAT  | DEC    | HEX    | BIN    |  R3
|        |        |        |        |        |
| 0x2F / | 0x30 0 | 0x31 1 | 0x32 2 | 0x33 3 |
+--------+--------+--------+--------+--------+
| CALC   | 4      | 5      | 6      | *      |
|        | FIX    | ENG    | SCI    | PREC   |  R4
|        |        |        |        |        |
| 0x34 4 | 0x35 5 | 0x36 6 | 0x37 7 | 0x38 8 |
+--------+--------+--------+--------+--------+
| f      | 1      | 2      | 3      | -      |
|        | p      | n      | u      | m      |  R5
|        | XOR    | AND    | NOT    | OR     |
| 0x39 9 | 0x3A : | 0x3B ; | 0x3C < | 0x3D = |
+--------+--------+--------+--------+--------+
| ON/OFF | 0      | .      |        | +      |
|        | k      | M      | G      | T      |  R6
|        | 1'S    | 2'S    | UNSGN  |        |
| 0x3E > | 0x3F ? | 0x40 @ | 0x41 A | 0x42 B |
+--------+--------+--------+--------+--------+

BOM

• Perfboard square grid of 0.1 inches, pads on both sides (plate-through holes), 2" x 3.5", $3
• SBC
  • STM32WB55 Dongle, part of P-NUCLEO-WB55, DigiKey 497-18384-ND
  • STM32F405
• OLED display
  • 128x32 pixels if it should fit into 2" x 3.5"
  • 128x64 pixels, Adafruit FeatherWing OLED - 128x64 OLED
• 35 pcs push buttons, fit in 0.4" grid
  • Würth 430473035826, DigiKey #732-7021-1-ND, data sheet, $0.5
  • TE Connectivity ALCOSWITCH Switches 1825910-6, $0.15
  • C&K PTS 647 SN50 SMTR2 LFS, DigiKey #PTS647SN50SMTR2LFSCT-ND, smaller 4.5 x 4.5 mm, $0.2
• Wires
• USB Connector e.g.
  • Adafruit USB Micro-B Breakout Board, DigiKey 1528-1383-ND, from $1 up
  • Adafruit Micro-Lipo Charger for LiPo/LiIon Batt w/MicroUSB Jack, $7
  • Adafruit Micro-Lipo Charger for LiPo/LiIon Batt w/USB Type C Jack, $7
• I2C Connector

-- Peter Schmid - 2024-05-24