Note 
The Thai alphabet has got several characters for a same phoneme. 
The transliteration is based on the Iso 11940 norm.
How to use 
To type directly with the computer keyboard:
 
-  Type = to change the consonant
 
- Type several times = to change the character of the same phoneme:
K= for ข ฃ ค ฅ ฆ 
s= for ซ ส ศ ษ 
C= for ฉ ช ฌ 
T= for ฐ ฑ ฒ ถ ท ธ 
P= for ผ พ ภ 
 
- Type d=, t=, l=, h= for ḍ   ṭ   ṇ   ḷ   ḥ 
 
- Type an apostrophe ' for the low tone, '' for the falling tone, ''' for the high tone, '''' for the risen tone
 
- Type -n for the final nasal
 
- Type ü or û or q for the vowel ụ
 
- Type aa, uu, ii, qq, for the long vowels and ee for æ
 
- Type a= for ạ; aa= for å; o= and o== for ị   ı 
 
- Type v= for ł
 
Download & install the font Noto Serif Thai 
Copy [Ctrl]+[C] & Paste [Ctrl]+[V]