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--- oak:tutorials:particle-function [2016/03/24 16:32]
jwhendy
+++ oak:tutorials:particle-function [2016/03/24 19:46]
jwhendy [Code]
@@ Line 1: / Line 1: @@
-**In progress!**
+===== Oak: using Particle.function() =====
-This is currently a copy of particle-variable to use as a template.
------
-===== Oak: using Particle.variable() =====
-[[http://digistump.com/wiki/_media/oak-rgb-led.png|{{http://digistump.com/wiki/_media/oak-rgb-led.png?400}}]]
 This tutorial is very similar to the one on [[http://digistump.com/wiki/oak/tutorials/particle-variable|Particle.variable()]]. This time, however we will be doing the reverse: //sending// data to the Oak. To accomplish this, we use ''Particle.function()''. As an example, we will send ''POST'' commands using ''curl'' to the Particle API which will control the color of an RGB led connected to the Oak.
@@ Line 24: / Line 16: @@
 |Resistor, 220 ohm| 3 | Red-Red-Brown|
-These are the same components used with the [[http://digistump.com/wiki/oak/tutorials/rgb-led#components_used|advanced LED tutorial]]. Feel free to substitute any resistor value between 100-1k ohms.
+These are the same components used with the [[http://digistump.com/wiki/oak/tutorials/rgb-led#components_used|RGB LED tutorial]]. Feel free to substitute any resistor value between 100-1k ohms.
 **Note:** You need to install [[https://curl.haxx.se/download.html|curl]] to push data to the Particle API.
@@ Line 195: / Line 187: @@
 Thankfully there are ways to split apart a ''String'' if you know the structure. There are several examples of various ways to pass multiple values to ''Particle.function()'' if you [[https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=pass%20multiple%20parameters%20to%20particle.function|search for them]]. We will use the one described [[https://community.particle.io/t/rest-api-arguments-is-there-a-better-way/960/2|here]].
+<code>
+// each color's brightness
+int bright_r = 0;
+int bright_g = 0;
+int bright_b = 0;
+// locations of the commas we'll find below
+int loc1 = 0;
+int loc2 = 0;
+int loc3 = 0;
+void setup()
+{
+  // just one function!
+  Particle.function("set", set_rgb);
+  // initialize each color pin as an output
+  pinMode(6, OUTPUT);
+  pinMode(7, OUTPUT);
+  pinMode(8, OUTPUT);
+}
+int set_rgb(String arg)
+{
+  // find the location of the first comma
+  // extract from 0 to the comma, storing the value
+  // as an integer
+  loc1 = arg.indexOf(",");
+  bright_r = arg.substring(0, loc1).toInt();
+  // find the next comma by searching starting at the last one
+  // extract from the last comma to this one
+  // store as an integer in bright_g
+  loc2 = arg.indexOf(",",loc1+1);
+  bright_g = arg.substring(loc1+1, loc2).toInt();
+  // repeat, taking the value between the last comma and this one
+  loc3 = arg.indexOf(",",loc2+1);
+  bright_b = arg.substring(loc2+1, loc3).toInt();
+  // write all three values to their respective color pins
+  analogWrite(6, bright_r);
+  analogWrite(7, bright_g);
+  analogWrite(8, bright_b);
+}
+void loop()
+{
+}
+</code>
+With only one function that can extract three values separated by commas, we can now pass an ''r,g,b'' formatted argument and have all three colors changed in one shot:
+<code>
+curl https://api.particle.io/v1/devices/id_goes_here/set \
+    -d access_token=token_goes_here
+    -d "args=1023,0,512"
+</code>
+That will turn on red all the way and blue halfway, creating a pinkish color. Play around with other value combinations and set some colors!
 ===== Conclusion =====
-And that's it for the basics of sending data with ''curl'' via particle.io! It's up to you what you send, and how you have the Oak respond to it. For one idea, check out the tutorial on using ''python'' to generate or collect data (say, from a local sensor) and send it to the Oak. The nice thing with these functions is that if you can do something on the Oak, you can make it happen when a command is sent with ''Particle.function()''; it's just a matter of slightly re-arranging your code.
+And that's it for the basics of sending data with ''curl'' via particle.io! We learned how to pass values, as well as to utilize one ''Particle.function()'' to set many values by sending them in a known format, combined with ''indexOf'' and ''substring()'' to separate them from one another.
+It's up to you what you send, and how you have the Oak respond to it. For one idea, check out the tutorial on using ''python'' to generate or collect data (say, from a local sensor) and send it to the Oak. The nice thing with these functions is that if you can do something on the Oak, you can make it happen when a command is sent with ''Particle.function()''; it's just a matter of slightly re-arranging your code.

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