This tutorial demonstrates how to use the Arduino to read in the analog input and update a ThingSpeak Channel by sending an HTTP POST via the Arduino Ethernet Shield or the Arduino Ethernet (all-in-one). The analog input can be the output of a sensor, like a light sensor or temperature sensor.
This Arduino sketch takes the value of Analog Pin 0 and updates Field 1 of a ThingSpeak Channel using the ThingSpeak API.
How to Change the Sketch
- Enter the Write API Key in this sketch you got under your individuelle “ThingSpeak Settings”
- The Arduino + Ethernet Shield does not have DNS by default, so you need to send data using an IP address. ThingSpeak has an API address dedicated for its API --> use this in your Sketch.
byte server[] = { 184, 106, 153, 149 }; // ThingSpeak IP Address: 184.106.15
- Watchdog Timer: Included in the sketch is a watchdog timer for the Ethernet Shield. When 5 failed transactions are detected in a row, the Arduino re-initializes the Ethernet Shield (soft-reset). This will not solve every lockup, but it will make the setup more stable.
- You can update multiple fields inside of a ThingSpeak Channel by adding on more fields in the update request. Here’s an example:
updateThingSpeak("field1="+analogPin0+"&field2="+analogPin1);
- The function “updateThingSpeak” is expecting a “String” as its input. So, if you use a “long” variable type, you need to convert the “long” into a “String” before passing it into “updateThingSpeak”.
Definition: long sensorValue = 6;
Loop: updateThingSpeak("field1="+String(sensorValue, DEC));
weitere Infos
- Testsketch für Thingspeak Sketch (Mai 2015)
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