I wrote a major mode for writing HTML entities encoding braille unicode characters. Here it is.
(defvar braille-mode-hook nil)
(defvar braille-mode-map nil
"Keymap for Braille mode.")
(defun braille-insert-punc (char) char)
(defun braille-insert-num (char)
(read (concat
"(lambda nil (interactive)(braille-switch-to-numbers)(insert \""
char
"\"))")))
(defun braille-insert-alnum (char)
(read (concat
"(lambda nil (interactive)(braille-switch-to-alpha)(insert \""
char
"\"))")))
(defun braille-insert-ucase-alnum (char)
(read (concat
"(lambda nil (interactive)(insert \"⠄\")(funcall "
(prin1-to-string (braille-insert-alnum char))
"))")))
(defun braille-insert-ucase-alpha (char)
(read (concat "(lambda nil (interactive)(insert \"⠄\")(funcall "
(prin1-to-string (braille-insert-alpha char))
"))")))
(defun braille-insert-alpha (char) char)
(defun braille-switch-to-alpha ()
(unless (eq braille-character-mode 'braille-alpha)
(setq braille-character-mode 'braille-alpha)
(insert "⠖")))
(defun braille-switch-to-numbers ()
(unless (eq braille-character-mode 'braille-numbers)
(setq braille-character-mode 'braille-numbers)
(insert "⠼")))
(defvar braille-character-mode nil)
(unless nil
(setq braille-character-mode 'braille-alpha))
(unless nil
(setq braille-mode-map (make-sparse-keymap))
(define-key braille-mode-map "," (braille-insert-punc "⠂"))
(define-key braille-mode-map "'" (braille-insert-punc "⠄"))
(define-key braille-mode-map ":" (braille-insert-punc "⠒"))
(define-key braille-mode-map ";" (braille-insert-punc "⠆"))
(define-key braille-mode-map "!" (braille-insert-punc "⠖"))
(define-key braille-mode-map "-" (braille-insert-punc "⠤"))
(define-key braille-mode-map "?" (braille-insert-punc "⠦"))
(define-key braille-mode-map "." (braille-insert-punc "⠲"))
;; (define-key braille-mode-map "\"" (braille-insert-punc "⠐"))
;; (define-key braille-mode-map "\\" (braille-insert-punc "⠳"))
;; (define-key braille-mode-map "!" (braille-insert-punc "⠮"))
;; (define-key braille-mode-map "#" (braille-insert-punc "⠼"))
;; (define-key braille-mode-map "$" (braille-insert-punc "⠫"))
;; (define-key braille-mode-map "%" (braille-insert-punc "⠩"))
;; (define-key braille-mode-map "&" (braille-insert-punc "⠯"))
;; (define-key braille-mode-map "'" (braille-insert-punc "⠠"))
;; (define-key braille-mode-map "(" (braille-insert-punc "⠷"))
;; (define-key braille-mode-map ")" (braille-insert-punc "⠾"))
;; (define-key braille-mode-map "*" (braille-insert-punc "⠡"))
;; (define-key braille-mode-map "+" (braille-insert-punc "⠬"))
;; (define-key braille-mode-map "," (braille-insert-punc "⠄"))
;; (define-key braille-mode-map "-" (braille-insert-punc "⠤"))
;; (define-key braille-mode-map "." (braille-insert-punc "⠨"))
;; (define-key braille-mode-map "/" (braille-insert-punc "⠌"))
;; (define-key braille-mode-map ":" (braille-insert-punc "⠱"))
;; (define-key braille-mode-map ";" (braille-insert-punc "⠰"))
;; (define-key braille-mode-map "<" (braille-insert-punc "⠣"))
;; (define-key braille-mode-map "=" (braille-insert-punc "⠿"))
;; (define-key braille-mode-map ">" (braille-insert-punc "⠜"))
;; (define-key braille-mode-map "?" (braille-insert-punc "⠹"))
;; (define-key braille-mode-map "@" (braille-insert-punc "⠈"))
;; (define-key braille-mode-map "[" (braille-insert-punc "⠪"))
;; (define-key braille-mode-map "]" (braille-insert-punc "⠻"))
;; (define-key braille-mode-map "^" (braille-insert-punc "⠘"))
;; (define-key braille-mode-map "_" (braille-insert-punc "⠸"))
(define-key braille-mode-map "1" (braille-insert-num "⠁"))
(define-key braille-mode-map "2" (braille-insert-num "⠃"))
(define-key braille-mode-map "3" (braille-insert-num "⠉"))
(define-key braille-mode-map "4" (braille-insert-num "⠙"))
(define-key braille-mode-map "5" (braille-insert-num "⠑"))
(define-key braille-mode-map "6" (braille-insert-num "⠋"))
(define-key braille-mode-map "7" (braille-insert-num "⠛"))
(define-key braille-mode-map "8" (braille-insert-num "⠓"))
(define-key braille-mode-map "9" (braille-insert-num "⠊"))
(define-key braille-mode-map "0" (braille-insert-num "⠚"))
(define-key braille-mode-map "a" (braille-insert-alnum "⠁"))
(define-key braille-mode-map "b" (braille-insert-alnum "⠃"))
(define-key braille-mode-map "c" (braille-insert-alnum "⠉"))
(define-key braille-mode-map "d" (braille-insert-alnum "⠙"))
(define-key braille-mode-map "e" (braille-insert-alnum "⠑"))
(define-key braille-mode-map "f" (braille-insert-alnum "⠋"))
(define-key braille-mode-map "g" (braille-insert-alnum "⠛"))
(define-key braille-mode-map "h" (braille-insert-alnum "⠓"))
(define-key braille-mode-map "i" (braille-insert-alnum "⠊"))
(define-key braille-mode-map "j" (braille-insert-alnum "⠚"))
(define-key braille-mode-map "k" (braille-insert-alpha "⠅"))
(define-key braille-mode-map "l" (braille-insert-alpha "⠇"))
(define-key braille-mode-map "m" (braille-insert-alpha "⠍"))
(define-key braille-mode-map "n" (braille-insert-alpha "⠝"))
(define-key braille-mode-map "o" (braille-insert-alpha "⠕"))
(define-key braille-mode-map "p" (braille-insert-alpha "⠏"))
(define-key braille-mode-map "q" (braille-insert-alpha "⠟"))
(define-key braille-mode-map "r" (braille-insert-alpha "⠗"))
(define-key braille-mode-map "s" (braille-insert-alpha "⠎"))
(define-key braille-mode-map "t" (braille-insert-alpha "⠞"))
(define-key braille-mode-map "u" (braille-insert-alpha "⠥"))
(define-key braille-mode-map "v" (braille-insert-alpha "⠧"))
(define-key braille-mode-map "w" (braille-insert-alpha "⠺"))
(define-key braille-mode-map "x" (braille-insert-alpha "⠭"))
(define-key braille-mode-map "y" (braille-insert-alpha "⠽"))
(define-key braille-mode-map "z" (braille-insert-alpha "⠵"))
(define-key braille-mode-map "A" (braille-insert-ucase-alnum "⠁"))
(define-key braille-mode-map "B" (braille-insert-ucase-alnum "⠃"))
(define-key braille-mode-map "C" (braille-insert-ucase-alnum "⠉"))
(define-key braille-mode-map "D" (braille-insert-ucase-alnum "⠙"))
(define-key braille-mode-map "E" (braille-insert-ucase-alnum "⠑"))
(define-key braille-mode-map "F" (braille-insert-ucase-alnum "⠋"))
(define-key braille-mode-map "G" (braille-insert-ucase-alnum "⠛"))
(define-key braille-mode-map "H" (braille-insert-ucase-alnum "⠓"))
(define-key braille-mode-map "I" (braille-insert-ucase-alnum "⠊"))
(define-key braille-mode-map "J" (braille-insert-ucase-alnum "⠚"))
(define-key braille-mode-map "K" (braille-insert-ucase-alpha "⠅"))
(define-key braille-mode-map "L" (braille-insert-ucase-alpha "⠇"))
(define-key braille-mode-map "M" (braille-insert-ucase-alpha "⠍"))
(define-key braille-mode-map "N" (braille-insert-ucase-alpha "⠝"))
(define-key braille-mode-map "O" (braille-insert-ucase-alpha "⠕"))
(define-key braille-mode-map "P" (braille-insert-ucase-alpha "⠏"))
(define-key braille-mode-map "Q" (braille-insert-ucase-alpha "⠟"))
(define-key braille-mode-map "R" (braille-insert-ucase-alpha "⠗"))
(define-key braille-mode-map "S" (braille-insert-ucase-alpha "⠎"))
(define-key braille-mode-map "T" (braille-insert-ucase-alpha "⠞"))
(define-key braille-mode-map "U" (braille-insert-ucase-alpha "⠥"))
(define-key braille-mode-map "V" (braille-insert-ucase-alpha "⠧"))
(define-key braille-mode-map "W" (braille-insert-ucase-alpha "⠺"))
(define-key braille-mode-map "X" (braille-insert-ucase-alpha "⠭"))
(define-key braille-mode-map "Y" (braille-insert-ucase-alpha "⠽"))
(define-key braille-mode-map "Z" (braille-insert-ucase-alpha "⠵")))
(defun braille-mode ()
"Major mode for writing braille for use in a browser."
(interactive)
(kill-all-local-variables)
(make-local-variable 'braille-character-mode)
(setq braille-character-mode 'braille-alpha)
(setq mode-name "Braille")
(setq major-mode 'braille-mode)
(use-local-map braille-mode-map)
(run-hooks 'braille-mode-hook))
(provide 'braille)