A 7-segment Alphabet with a Unique Pattern for Every ASCII Character -- Dave Keenan, 29-Sep-2018 Below is a complete reversible mapping from ASCII to 7-segment. It includes 7-segment glyphs for all non-printing characters except null, with the idea that this mapping could also be used for a chording keyboard, with 7 keys arranged like the segments of a 7-segment display. But for normal output, non-printing characters would not be shown. It could also be used in a manner similar to braille or seikoo. This mapping obeys the following principles: 1. No two ASCII characters have the same shape. 2. The decimal digits have their standard shapes. 3. The other hexadecimal digits have their standard shapes as uppercase A C E and lowercase b d f. 4. We don't assume a decimal point will be available. 5. No shape strongly resembles a character it doesn't represent. 6. These pairs must be mirror images of each other: <> () [] {} /\ bd pq. 7. These pairs must be inversions of each other: nu mw NU MW `, ^v bp dq ft. 8. The mw shapes must appear larger than the nu shapes. Some emergent rules (or mnemonics) turn out to be: 9. Where, in a conventional font, an upper/lower case pair have much the same shape, and cannot be distinguished by height in the 7-segment font, i.e. fF kK pP mM sS wW zZ, then in the 7-segment font, the most exploded one is the uppercase. 10. The patterns for the non-printing characters that have their own key on a conventional keyboard, namely Esc, Tab, Delete (del), Backspace (bs), Return/Enter (cr), Page-down (ff) and Space (sp), are such that they can be typed on a 7-segment chording keyboard with one finger, and are located in the same relative position that they are on a conventional keyboard. See the keyboard diagram at the end of the article. 11. Control characters sometimes have glyphs that are the mirror image of the corresponding printable character, either lowercase: ^c ^f ^t ^y or uppercase: ^J ^K ^R ^V. Others have glyphs that are the corresponding character (upper or lower case or both) with one or more segments missing: ^Aa ^b ^Dd ^Ee ^Gg ^p ^q ^Ss ^Z If you choose not to distinguish upper and lower case letters on output, to improve readability, the preferred glyph for each letter is indicated by a caret below it. These correspond to: AbCdEfGhiJkLMnopqrStuvWXyZ. Also for readability, Ss and Zz may be displayed using the same glyphs as 5 and 2 respectively. _ _ _ _ _ _ _ | _ | |_ _| | | |_ | | _| _| | | | | | _| | | _ | | |_| | | | _ | 00 45 34 4C 16 68 47 25 02 60 3C 17 46 42 2B 05 ^A ^B ^C ^D ^E ^F ^G ^J ^K ^N ^O _ _ _ _ _ | | | | | | | _| | | _| |_| | | | | | | | _| _| |_| _| | | _ |_ |_ | |_ | _ 32 26 27 2C 4E 1D 2E 14 4A 7A 1A 21 12 19 11 28 ^P ^Q ^R ^S ^T ^U ^V ^W ^X ^Y ^Z ^\ ^] ^^ ^_ _ _ _ | | | | | _ | |_| | _| |_ |_| |_ _ _| | _ | | _ | |_| |_ _| | _| _ | 44 0A 22 36 49 24 7E 20 5A 6C 63 70 0C 40 08 52 ! " # $ % & ' ( ) * + , - . / _ _ _ _ _ _ _ _ _ _ _ _ _ | | | _| _| |_| |_ |_ | |_| |_| |_ _ _| _| |_| | |_ _| | _| |_| | |_| _| _ _| _ | 3F 06 5B 4F 66 6D 7D 07 7F 6F 09 0D 61 48 43 53 0 1 2 3 4 5 6 7 8 9 : ; < = > ? _ _ _ _ _ _ _ _ _ _ _ _ _ _ |_| | | | | |_ _ | |_| | | | | | | | | |_| | | |_ |_ |_| |_ | |_| | | _| |_| | | |_ | | | | _| 5D 77 3B 39 1F 79 51 3D 76 0F 1E 35 38 15 37 2F @ A B C D E F G H I J K L M N O ^ ^ ^ ^ ^ ^ ^ _ _ _ _ _ _ _ _ _ _ | |_| | | | | | | | | | | _| |_| | | |_ | | | | _ | _| | |_| |_ _ | | | |_ _ | _ |_ 13 6B 33 2D 31 3E 3A 2A 57 72 1B 29 64 0B 23 18 P Q R S T U V W X Y Z [ \ ] ^ _ ^ ^ ^ ^ _ _ _ _ _ _ _ | _| |_ _ _| |_| |_ |_ |_ | |_ | _ _ _ |_| |_| |_ |_| |_ | | | | | _| | | | | | | | |_| 03 5F 7C 58 5E 7B 71 65 74 10 0E 75 30 55 54 5C ` a b c d e f g h i j k l m n o ^ ^ ^ ^ ^ ^ ^ ^ _ _ _ _ _ _ _ _ |_| |_| _ _ |_ |_| |_| _| |_| _ |_ _| _ | | | _| |_ |_| _ | | _| |_ _ | _ 73 67 50 4D 78 1C 62 6A 56 6E 59 69 04 4B 01 41 p q r s t u v w x y z { | } ~ ^ ^ ^ ^ ^ ^ ^ __0_ _01_ 5 1 20 02 |__6_| |_40_| 4 2 10 04 |__3_| |_08_| bit nums bit values The diagram below shows a 7-key chording keyboard with its keys arranged like the segments of a 7-segment display. One finger can press 1, 2 or 3 keys at once. The diagram shows the finger placements for the 25 characters that can be typed with one finger, and the 8 characters that can be typed with two fingers diametrically-opposed. There are another 64 characters that can be typed with 2 fingers. Only the following 30 characters require 3 fingers: ^K ^N ^U ^V ^Y & 0 6 8 9 @ A B D G K M N O Q U V W X a e k m w y %-------C---:---I-------^\ | | | | | esc ~ ` | | | | | " ' <--del--> bs " | | | | | tab cr | | | | | #---l---+ - ff---1---# | | | | | r sp | | | | | ^W i c---=---^C | ^W | | | | | _ . , | | | | | ^\-------C---:---I-------% -- Dave Keenan, 29-Sep-2018