[UPDATED] ESP8266 WiFi Sensor - temperature and humidity

---

[Update] 10.06.2015:

• Added Server Arguments. It is now possible to change the variables via the WebUI (pimatic server IP, device name, etc)
• (Basic AP Mode coded but currently not working because of EEPROM.h bug and wifi.mode switch error. )
• still hard coded variables -> WiFi SSID, WiFi Password, and mDNS Name

[Update] 03.06.2015:

As the memory limitations of the lua script got out of hand I moved the whole project to C Code via esp8266Arduino. It’s basically the same but with some improvements:

• adaptive WebUI based on Bootstrap (scales to Windows size)
• mDNS Support: Device will be found as http://<device-name>.local in your network. No need to remember the IP Address anymore. E.g. http://kitchen.local or http://bedroom.local
• Uptime Timer
• Current Temperature and Humidity avaible on WebUI

Code avaible at esp8266-pimatic-Arduino.

Screenshot Wide:

Screenshot Small:

ToDo:

• As of now the Configuration Page is Work in Progress and you have to edit some varibles in the .ino file while I’m currently cleaning up the code.
• SoftAP Mode when no credentials are given and EEPROM usage as DB --> final firmware without need to edit any .ino-file, just burn it (like the lua firmware) and configure everything else via WebUI

HowTo:

• Install the Arduino IDE and head over to https://github.com/esp8266/Arduino to get help with the Setup.
• Prepare your Hardware http://www.arduinesp.com/wifiwebserver (this is far more complicated …)

Don’t hesitate to post or pm me if you have suggestions or problems.

[Original Post]:

Hi,
I just wanted to share a simple lua script to send DHT22 temperature and humidity data to a pimatic server instance via HTTP PATCH over WiFi.

If anyone finds some bugs or has some improvements, feel free to leave me a note. At the moment it is limited to one esp8266 but I will update the code if I get my hands on more of them.

esp8266-pimatic

additional info:

WebUI:

Hardware:

ESP8266:
The esp8266-01 (costs about 3€) is working without any additional controller. So you dont need to attach an arduino. It has built in WiFi and has two GPIO Pins to use.

Power Source:
The power consumption is about 215 mAh when it sends data over WiFi. This is just for sending packages so in between it should only use like 10 uAh or something like that (source). Therefore it is possible to run the esp8266 with two AA batteries á 1,5V (could be dangerous because of the irregular drain curve; better use rechargeable ones á 1,2V and three of them) or like me with a mobile USB battery pack . Here you need an additional Step-Down Voltage Regulator (e.g. AMS1117-3.3) to get from 5V to 3,3V. (!) It’s important to note that the esp8266 only accepts 1,7V - 3,6V and is easily destroyed by providing a voltage too high.
So battery life drastically depends on how often you want to send the data to pimatic. I only have a mobile battery pack (10400 mAh) which is way overpowered. Don’t quote me for this but I think three AAA rechargeable batteries or less would easily last over a year.

DHT22:
Standard DHT22 Sensor you can get for ~4€. Don’t forget to add an resistor (4.7K) between VCC and DATA (schematic).

UART-Adapter:
USB Adapter to set up the esp8266 (flashing, serial console, …)

Software:

Firmware:
I’m using the nodemcu firmware for the esp8266 as it is really simple to write code in lua.

HowTo for flashing:
There are really great tutorials out there and therefore I will just link to them.

Flashing the firmware
Nodemcu Github (API documentary etc)

IDE:
ESPlorer. Easy to use IDE for ESP8266 and built in Terminal (JAVA based).

Just as a side note. If your are using the UART adapter as a power source it could randomly crash as it does not provide enough mAh in wifi mode. It really is only good enough to flash the device. In testing phase it is really great to have an breadboard with a power supply (e.g. YwRobot; but it is not needed).

Changelog:

• 07.05.2015
  – Added WebUI to configure ESP8266 from within the browser (screenshot above)
  – no reflashes needed to change pimatic Server IP or Device PIN, …
  – added base64 code, just enter “username password” as credentials; no encoding required; the esp8266 will encode the credentials for you
  – avaible options: Credentials, Pimatic Server IP, Data Send Interval, Data PIN, Device connected (DHT22 or DS18B20)
  – shows current configurations
  – way bigger code. Therefore you must compile all files except init.lua (either with node.compile("<file>.lua") or with ESplorer)

Bugs:

• Changing the Interval will reset the esp8266. You have to reenter your Configurations.
• DS18B20 is untested, but should work out of the box

@okadesde great, do you need an arduino for that?
what kind of esp8266 are you using?
could you describe the wiring?
is it running on battery?

Yeah no problem. Will update the post with more detailed info.

@okadesde Thanks for sharing!
I’ve done something similar for the DS18B20 temperature sensor and used your setup as basis.

It’s on github: https://github.com/georg90/esp8266-pimatic

Also some pictures for wiring etc.
As I have 12v running outside, I used an old usb charger to get from 12v -> 5v and a step down adapter for 5v -> 3.3v

hey guys, keep up the good work!!
I like what you’re doing

Very good and interesting i will try this as well (and hope to be able to use interruption to monitor gas and electricity consumption).
Thanks for having shared that!

Excellent. I am looking forward to checking this out.

@georg90 : I try to get the ESP01 running with an DS18B20. From the ESP point of view it looks good. I have following log:

NodeMCU 0.9.5 build 20150213  powered by Lua 5.1.4
Setting up WIFI...
> IP unavaiable, Waiting...
Config done, IP is 192.168.1.26
Total DS18B20 sensors: 0
Temperature: 23.6875?C
23.6875
Content-Length: 47
Sending data ...
Closing connection
Got disconnection...
Total DS18B20 sensors: 0
Temperature: 23.625?C
23.625
Content-Length: 46
Sending data ...
Closing connection
Got disconnection...

However my pimatic don’t get the data.

my config of main.lua:

lasttemp=-999
-- GPIO2
pin = 4
contentLength = 0
-- user:password (pimatic) in BASE64; ex. "dXNlcjpwYXNzd29yZA=="
base64login = "the value of "secret" inside config.json"
-- pimatic server IP
pimaticServer = "192.168.1.5"
pimaticPort = "8081"
-- Pimatic variable which should be updated
variableName = "aqua-wifi-temp"
-- send data every X seconds
interval = 30

in pimatic I have defind a new variable: $esp01-aqua-wifi-temp
its value is always 0. where is my mistake? how to debug?

I’m having problems flashing them from windows, any one else got that problem?
Havent tried fron linux yet.

@Tomasz said:

its value is always 0. where is my mistake? how to debug?

Hi!
I will switch to a DHT22 soon, since it will provide Humidity as well

Edit you value in pimatic manually to something weird like -999 Does it get updated to 0?

I didn’t try the secret from the pimatic config for the base64login I simply put my User:Password on this website to get the encoded version: https://www.base64encode.org

Probably that’s it?

@georg90

OK, thanks. My base64login was wrong. I have used the value that I got from https://www.base64encode.org and now it works.

The DS18B20 is perfect for me, I want to measure water temperature with an waterproof sensor.

@georg90 Great idea. I added the DS18B20 library to my code too ^^.

Updated my code with a WebUI to easily configure the es8266 without the need to reflash it everytime. It was quite a hassle with several of these clients in my network to connect and reflash them everytime just to change the interval measurements or the IP of the pimatic server.

Have fun ^^. I greatly appreciate any help with the code as mine is not very clean. But for now it works and won’t crash ^^.

@okadesde Haha, I was developing the same^^ I really like your GUI! Do you password protect it?

Now I’m very busy in life, so I’ll give it a try when I have time.

@georg90 thanks ^^. I thought about implementing password protection but it would be too difficult to secure it probably. And too much for the esp8266 (https). But I would gladly accept any ideas ^^. For now I’m concentrating on the reset bug which is far more annoying ^^.

I will check options for a easy password solution.
What reset bug? My node is not sending anymore…will flash your software once I get some free time

I couldn’t get the tmr.alarm() function to reset itself to run with a new interval. I enclosed it in a while true loop and a break point in tmr.alarm() to check for a new interval but this didn’t work (don’t know why, just got cryptical outputs and a restart).
Therefore I included a check for changes in response.lua which writes the new interval in time.lua and restarts the whole esp8266 with node.restart(). But this has the affect that all other settings must be typed in again.

It is a very interesting project.

So I try this code to an esp8266 (esp-01)
I use esplorer from windows but i have an error “not enough memory” when I save to esp the main.lua
All the others files doesn’t have problems…

Can anyone help with this problem?

@Panos Thanks for the reminder. You have to compile all the files except the init.lua. Then its far more resource friendly and should run without memory issues. Will add this info to the main post.

@okadesde I have send to esp only the main.lua. ( no others *.lua )
But i can not compile it … same error "not enough memory"
May be I am doing something wrong…

@Panos You need all .lua-files on the esp. Please transfer: base64.lua, dht22.lua, ds18b20.lua, init.lua, main.lua, response.lua, temperature.lua and time.lua.
Yes, I randomly had these compiler problems too. Just format the whole esp and transfer and compile the files step by step. Would be nice to just flash a .bin image with everything preinstalled but couldn’t find a way to do it.