Unusual tuner idea?

[Mgt280y]

To most this is probably a pointless project but potentially a easy and useful one for me
Would it be possible to make a small stomp box that could recognise a single note, I play the sax so tuning up is done on a single note + Octave, could I make a pedal with 3 LEDs and a true bypass switch, thinking #1 led flat #2 led tune #3 led sharp and it would only need to recognise one note
Is this achievable and would it be accurate
Thanks dan

[Phoenix]

It's achievable yes, but with significant effort. The question is whether it's worth the investment of time and materials for something that has no "tone" as such, when there are a great many very cheap offerings available that do exactly this already available on the market, that will most likely be more accurate than any simple DIY approach. Sure, you may be able to out-do the commercial offerings with significant effort, but if you need that sort of accuracy, even strobe tuners are becoming quite affordable, and you're not likely to top one of those.