Arduino, Using Cable or WiFi (ESP8266) or Use ESP8266 Alone Despite how simple it is to set up, Thingspeak has a few obstacles that I encountered and, based on responses, other users appear to be having trouble with as well. This project works well, but I probably wouldn't use an

Arduino and an ESP8266 together again because it is too much. The Arduino can do a lot of things that the ESP8266 can also do, especially if all it needs to do is gather data from sensors. Check out the "ESP8266 only" step of this project or one of my more recent ones, like this one.

Arduino WS5100 EthernetShield Thingspeak Account Sensors (such as DHT11 and BMP180) Internet connection

ESP8266-01 (or other ESP8266 I wanted to use my Arduino to gather weather data and put it on a website in the form of nice graphs so I could keep an eye on it from far away. I could just use an Arduino as a web server, but if I want to do more than send numbers to a webpage, the Arduino will soon run out of memory. There are

services that can take your data and make it public: Pachube, which changed its name to Xively, is well-known, but there is a waiting list for their free accounts right now. I really do have a Pachube account that became a Xively account, but I never got any results from it.

http://2lemetry.com http://exosite.com https://www.carriots.com https://www.grovestreams.com https://thingspeak.com http://openenergymonitor.org I chose "Thingspeak." I won't go into too much detail about the signup process or creating a channel or anything else because it's pretty straightforward and easy to understand. After you sign up, you basically make a channel and add fields to it where sensors will send their data later. Under the API tab, you'll find an API that you'll need to add to your programme later. I talk about a simple connection with an ethernet cable and a wireless connection. Step 1: Hurdles and Solutions Hurdle 1 Where do I look for a programme? Wouldn't it be nice to have an example that works? In the upper right corner, there is a "Support" button that takes you to "Tutorials."

"Updating a ThingSpeak Channel with an Arduino and an Ethernet Shield"

Sounds great, so you download that programme to your IDE, add the API key, and then compile it. Darn, it doesn't compile, and you try to fix it (which is certainly possible) until you don't know what's needed. The programme still seems to think that everyone will use the 022 or 023 IDE. There is a link to a Github page, but that will give you a programme to tweet, which is not what you want, at least not right now. Solution

https://github.com/iobridge/ThingSpeak-Arduino-Exa... That programme reads the A0 port and sends that information to "Field1" in your datastream. Ok, so you try that. You put a variable resistor like an LDR or NTC on port A0, add your API to the programme, and run it. That works fine, but I didn't just want to read a value from an analogue port. I also had a DHT11 Moisture Temperature sensor and a BMP180 Pressure & Temperature sensor. I didn't think it would be too hard. Hurdle 2 I made sure the Thingspeak programme had the right libraries, added the objects, and read the sensors into a variable. Thingspeak, on the other hand, wants you to send strings, but the sensors return floats.

Most variables can be turned into strings with the simple "string" function, but floats are a bit trickier. You have to use the "dtostrf" command, which I think stands for "double-to-string-function," to work with floats. When I tried to find information about that function on the Internet, I quickly found endless discussions about how "stupid" it was, and people who asked questions were often told, "Why would you need that? Serial.print will do that for you." Yeah, that's true, but I don't want to print. I need it because Thingspeak wants it. Solution To use the dtostrf command, you must set up a buffer space where the string

It's important to have bufferspace. I got it to work with "7" or even "5", but when I added a second sensor that needs this function, my datastream would crash or I would get the strangest results. I also thought I could switch between using the same bufferspace for each sensor, but that didn't work either, so now I have a bufferspace for each sensor. Now, I'm no expert in C, so if there's a better way to do this, I'd love to hear it, but this is what I did and it worked. Hurdle3 Once I knew how to convert strings, I was able to add the data to the datastream. The Thingspeak example programme only shows this for one field, but it's easy to see that you need to add the strings and use the right number of plus signs and ampersands. Solution

updateThingSpeak("field1="+temp+"&field2="+humid+"&field3="+pres+" &field4="+temp2 Step 2: Connecting with Ethernetshield The BMP180 is like the BMP085, but it has been updated. The BMP180 can use the libraries from the BMP085. There are two versions of the library for AdaFruit. I chose version 1 because it was easier to use. Version 2 also needs the "Sensor" library to be installed.

In the code, I also include an extra float:'m,' which gives the pressure in "mmHg." Since I haven't used it yet, there is no string conversion and it isn't added to the datastream, but adding it should now be as easy as adding 1 and 1. Step 3: Connect to Thingspeak Using an ESP8266 WiFi Module The internet connection shown before was made with a cable. But the Arduino can be connected to a cheap WiFi module called the ESP 8266. A cheap WiFi module is the ESP8266. Remember that it requires 3.3 Volt. Some models, on the other hand, say they can work with 5 Volts. I added two circuits that can be used to change the voltage. The ESP8266 needs its own source of 3.3 V because the current from the Arduino just isn't enough. There is a lot of information about how to connect the module, but I want to talk about the software needed to connect to Thingspeak. For debugging, the SoftSerial library is added. Once the programme is running, it is not really necessary. All of the print statements to the Software serial port are the same. I use 3 analogue values instead of an example with the BMP108 and DHT11 because that would require libraries. This makes it easier to understand how to use the ESP8266. Once you know that, adding other sensors is easy. Just make sure that everything is turned into a string. NOTE AT+CIOBAUD is no longer supported in the latest version of the ESP8266 firmware, which is why it returns ERROR.

AT+IPR is the command to use instead. See www.esp8266.com/viewtopic.php?f=13&t=718 for more information. More note It seems that some people have been having trouble lately because they connected the ESP8266 to the software serial instead of the hardware serial. This programme needs an ESP connected to a serial port. Step 4: Using Just the ESP8266 If you see gibberish on this page, it's because there was a full step here, but our thought it would be better to replace it with gibberish, even though I had already saved it. I will try it again. In the last step, I used an ESP8266 to send to Thingspeak the sensor values that an Arduino read. But you can also do it without using an Arduino at all. I connected a DHT11 to pin 2 of my ESP8266-01 and ran the following programme. I can't take all the credit for the programme. I think Jeroen Beemster came up with it first. This idea is not about how to programme the ESP8266. There are plenty of other places to learn that. If you already have a USB-TTL module at 3.3 Volt, you don't have to worry about voltages. If all you have is a 5V USB- TTL module, you can still use it, but you have to put a voltage divider between the module's Tx and the ESP8266's Rx. Never ever give the ESP8266 5 volts. Note: The Adafruit DHT library has a mistake that usually doesn't show up when using an Arduino, but can when using an ESP8266, especially if the programme is a bit larger. Changes you need to make to the cpp file are shown in the picture. It's mostly just comments on two lines.