(Catch up on the pi-dial series of blog posts.)
In addition to controlling the volume of my receiver’s Zone 2, I want to be able to use a second rotary encoder to change the input. For example, I may want to change it from the Phono input that I use to listen to records to the Tuner input to listen to the radio.
The Denon AVR-3806 that I own has twelve total inputs, of which I’ve customized a few of the names. If I print out the list using the
denonavr library, I see:
All inputs: ['8K', 'AUX', 'AppleTV', 'Bluetooth', 'HEOS Music', 'Phono', 'Retropie', 'SOURCE', 'TV Audio', 'Tuner', 'UBP-X700', 'Vinyl', 'Xbox One']
I’m using Python, so iterating through the list and / or slicing it to get to a specific position in the list shouldn’t be hard. Shouldn’t being the key word.
Spoiler: It was anything but.
If I attempted to iterate through the list, whenever the list position was equal to 8K, Bluetooth, or Source, the list would stop. It didn’t matter if I tried to move up or down the list. Now shame on me for not blogging about this earlier as it’s been almost two months since I worked on this particular piece, because I think there was another position in the list that did something similar. But of course I don’t have great notes or even a lot of commits to go back and look through.
I’m still very much a novice at coding, so I did what most newbies do. I wrote multiple if / else statements to try and figure out how to get around this limitation. I was 100% sure it was my code. Nothing I did worked, even as I wrote very procedural code to step through the list. I was on vacation the week I worked on this and spent literally the entire week trying to get this to work.
I finally broke down and asked my wife for help. In about five minutes she ripped up my if / else statements and wrote a methodthat passed a variable on whether the rotary encoder was turning up or down. And then she ran into the problem where the list would get stuck on positions 0, 3, and 7 (8k, Bluetooth, and Source) as you can see in the code’s comments. A couple hours later she was able to work around it. This was a fun way to spend a Friday night together!
Neither of us have any idea why those inputs caused the issue, but she was able to write a method to work around it.
The good news is that it wasn’t necessarily my code, the bad news is that I still have so much to learn about the best way to write my code.
The better news? The code is done! I have one program that monitors the current input and volume and displays it on the LCD and I have another program that can change the inputs and the volume.
Next up: 3D printing the enclosure.