I had a number of design goals making this project:
- I wanted it to be simple, mostly use parts I had on hand (to avoid the "why do you need to buy more parts? You have so many parts!" discussion)
- I wanted it to be cheap: where I didn't have parts, I wanted to buy as few as possible
- I wanted it to be fast and easy to use: if it wasn't as convenient as a remote control (or not as functional), it wouldn't get used
I had an ESP-01 module already on hand, and I wanted to use it - I didn't want to have to buy another ESP module with more GPIO available or anything like that. I knew I would need IR LEDs, and figured I'd have to buy a mosfet since they can consume up to 100mA. I had 3.3v linear regulators and disposable USB cables on hand already, along with some 22 gauge solid-core hookup wire.
If I'm going to use my phone for 1 remote, I may as well use it for all of them - so I wanted to make it multi-protocol so I could handle different brands - even among my small collection of A/V equipment, I have different required modulation frequencies, bit timings, etc.
My build log details more of my thought process, but these were some of my considerations in designing - I could have rolled my own circuit board and gone way more in depth on this project (and considered it), but simple design and fast iteration won out.