Greetings,
    I'm making an Arduino web server that displays various information, mostly power outage data, via HTTP. Then agents on smartphones call the site and parse the data. Such as a widget that will tell you if and how long the mains electric is out. (Had some water damage previously.)


    Being an unattended web server with a public dynamic IP address, it need DDNS. For this service, I use duckdns. After calling the API, I get the following error "HTTP/1.1 400 Illegal character 0x11 in state=URI in 'GET" I'm not quite sure what to make of it or where it comes from so I cannot correct the problem. I looked up the 0x11 character and it is not clear.


Example Program flow:
1. Hold button until 6 secs or yellow light.
2. Call DynamicDNS()
....2.1 Get public IP -> Fetches correct IP
....2.2 Call DDNS API to update the record. -> Error


I had to edit out api keys, domains, and public IP addresses. Any IPs included is already public knowledge.

Serial output:

valid static setup
DNS passed
IP:  192.168.1.114
GW:  192.168.1.1
DNS: 8.8.8.8
netmask: 255.255.255.0
Fetching Temps: pass
mode #1: reset dth11 and get rtc data
Fetching Temps: pass
mode #2
dns pass: myexternalip
IP IP: 78.47.139.102
<<< REQ1
.
.
.
.
.
>>> IP
status:0
HTTP/1.1 200 OK
Server: nginx/1.10.3
Date: Sun, 20 Aug 2017 16:57:58 GMT
Content-Type: text/plain
Content-Length: 12
Connection: close
Expires: Sun, 20 Aug 2017 16:57:57 GMT
Cache-Control: no-cache

50.[CORRECT PUBLIC IP*].51
...
dyn1:1

ip1:50.[AS ABOVE IP].51

dns pass: duckdns
DNS IP: 54.191.157.42
<<< REQ2
...
dyn2:1

>>> DNS
status:1
HTTP/1.1 400 Illegal character 0x11 in state=URI in 'GET /G\x11<<<\x04 HTTP/1.0\r\nX-Rea...: text/html\r\n\r\n>>>Amzn-Trace-Id: Ro...\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
Date: Sun, 20 Aug 2017 16:58:16 GMT
Content-Length: 0
Connection: close
Set-Cookie: [REMOVE]5uA8; Expires=Sun, 27 Aug 2017 16:5

Sketch: (Kind of long. Takes 80% Arduino Uno memory and prog space.)
https://pastebin.com/ZtjUfUrC


On a side note, this works with the api call:
char newIP[] = "123.123.123.123";
But I need to fetch the current IP and then assign it to a var before passing it to the API. Also, don't worry about the unoptimized code. I haven't got it working yet so I'll do that later.

Would anyone care to share some light on the error or solution?
    Thanks,

It depends on how long you want ot run it, but a pair of 18650s might be a good place to start, or 6xAAs NiMH.

I have limited space so please suggest small size but powerful batteries to run this system

I think you missed step (6); comment out every reference to the listen() method.

se utilizzo il pin 5 e 6 per comandare dei ventilatori, dal codice sotto posso modificare le uscite ? Ad esempio inserendo 10 e 11?  

LiquidCrystal lcd(7,6,5,4,3,2);

Hi Rob,

Thank you for the response. I have tried Dht11 DHT11; before with no luck (I am case sensitive).

Please note that revmike does not even include the instance (Dht11 DHT11). I added this in desperation.

I do notice that if I type DHT, the IDE sketch highlights it in red and if add 11 (Dht11) then it's back to black. Seems to me that Dht11 (Andy version) is not recognized(?)

My Library manager itemises Adafruits DHT11 before Dht11 (Andy's version). Maybe the IDE is selecting Adafruit DHT11 by default - before Andy's Dht11(?)

Other than that, the manufacturers claim 5%RH resolution and I tend to believe them. My 5 samples show variances of more than 40% and I do not believe these are original items - more likely rejects from Fong Kong knock-offs -  sold cheaply on the internet!

All the above is irrelevant, I'm going to throw this in and chalk it up as it is a waste of time.
Maybe I will order an A grade sample from the original manufacturers and retry!

Thank you for your time.