Building a Philips Hue Bulb Controller

For this assignment, we were tasked with building an Arduino-based device capable of connecting to and manipulating a Philips Hue Bulb via its Zigbee radio control hub. This assignment was our class’ foray into HTTP protocols – the week prior, we had completed this assignment in the command line of our computers.

I intended for my device to have 4 features – an on/off button, and three sensors which could control the hue, saturation, and brightness values of the bulb respectively. Initially, I intended on using three rotary encoders to manipulate these values, but I ended up using three potentiometers as I discovered that my rotary encoders were broken. Unfortunately, I documented poorly for this assignment, but I will do my best to communicate the two biggest problems I ran into in trying to complete this assignment:

  1. Putting the Cart Before the Horse in Wiring

Once I developed what I believed to be functional code based on an amalgamation of Tom Igoe’s Hue Control examples, I soldered my rotary encoders and wired them to my breadboard with my prototype on/off button. This was a mistake because in testing the inevitable bugs that ensued from my untested code, I was unable to discern which issue to solve first: the noise from my rotary encoders that made their values useless or my inability to send any HTTP put requests to the hue hub.

I ended up deconstructing my circuit and adapting my code to a switch to test if my put request code worked – first by turning the bulb on and off, then by having the bulb change between two colors in response to my switch being flipped. After realizing that it did, I scrapped the idea of working with my (poorly soldered) rotary encoders and decided to switch to working with a potentiometer. Before continuing, I wrote code that tested if I could manipulate the hue bulb’s brightness characteristics with one potentiometer, tested it, and made sure it worked.

2. Integrating Multiple Sensors Poorly

I spent the brunt of my time trying to integrate my on/off switch, and my potentiometers as separately read entities in the concatenated string HTTP put request that determines the condition of the hue bulb.

Test of one potentiometer for brightness, one on/off button prototype

First, I realized that my switch code was providing too much feedback, or “pinging” the hue hub too frequently, particularly in conjunction with the strings coming from my one potentiometer. I ended up changing the code and hardware to that of an “on/off” push button.

Second, in including two other variable changing potentiometers I somehow disrupted my code in a way that represented the potentiometers’ values in Arduino’s console log but did not put request their values to the hue hub – I have left the code that I used to confirm that my potentiometer values were sent in my final code file.

Had I pre-written conditions within each loop that debounced the put requests from the respective sensors I would have saved myself a lot of time in the integration of my sensor code into one file.

I still have not understood what aspects of my code have prevented me from cleanly and consistently manipulating different hue variables with all of my potentiometers. I will meet with Tom Igoe and update my blog to reflect this understanding.

What I’d Want to Do Moving Forward With This Project:

I would like to implement the following:

  1. Make the LED in my on/off push button work to represent if the bulb I’ve connected to is on or off- I ran out of time and could not figure out how to write the code that would accomplish this.
  2. Add a feedback screen – though I would not have had time to add it to this project while I was working on it, I had ordered one and it came too late for me to even attempt to integrate.
  3. Try and make my hue-bulb connection feedback faster, and more consistent. Even though I included debounce code in Millis, and took out much of the delays in my code my device had a noticeably slow “influence” on the bulb, I believe in part because I was still overwhelming the hue hub with my put requests.

Final Product:

Circuit Diagram

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