This issue affects Wi-Fi enabled bttns manufactured before March 2015. All new bttns have a newer firmware that can handle most printable ASCII characters except comma and umlauts when using WPA/WPA2. See a list of allowed special characters at the end of this page.


The Wi-Fi chip used inside bttns manufactured and shipped between December 2014 and February 2015 cannot at the moment join a network that has spaces or special characters* in its SSID or password. Reason: The chip's own setup tool does not understand the characters.


Also bttns running March 2015 firmware have this issue with open networks (i.e. networks without password).


If you can, create a guest Wi-Fi network that has no spaces or special characters in its SSID/password to use with bttn. Another option is to use mobile data connection.


* What are special characters then?


- All characters that the setup form's GET action converts into percent-encoded format, including spaces. Letters, numbers and dashes ('-') do work.


Which special characters are supported in new firmware (March 2015)?

The following list contains tested special characters that work both in SSID and password fields. Currently known exceptions are umlauts (ä, ü, etc.) and comma (,).


Char Decimal Hexadecimal
space 32 20
! 33 21
" 34 22
# 35 23
$ 36 24
% 37 25
& 38 26
' 39 27
( 40 28
) 41 29
* 42 2A
+ 43 2B
, (not supported) 44 2C
- 45 2D
. 46 2E
/ 47 2F
: 58 3A
; 59 3B
< 60 3C
= 61 3D
> 62 3E
? 63 3F
@ 64 40
[ 91 5B
\ 92 5C
] 93 5D
^ 94 5E
_ 95 5F
` 96 60
{ 123 7B
| 124 7C
} 125 7D
~ 126 7E