I am working on a will-call system where I can push a button in an app and light up one of 300 led lights in order to find a specific customers bag of merchandise. So far I can light one led using arduino/blue tooth/iphone. How do I get to choosing one of 300 leds using arduinos/signal/ipad, ect.
Welcome to the forum
Easy using WS2812 addressable LEDs (NeoPixels) and it only takes one Arduino pin
And a suitable PSU.
The leds have to be single, not in a strip. One light, one bag times 300. Maybe 300 arduinos and 300 individual led lights with one control app.
No problem with individual WS2812s but it may be interesting to connect them. What sort of shape will they be in and how far apart ?
Individual (non-strip) WS2812. You can also buy the chips with your own LEDs.
Or, you can use Shift Registers to address almost unlimited number of LEDs. This requires 3 output pins (data, clock, latch) but the programming is simpler and it only requires one bit of memory per LED (38 bytes for 300 LEDs) for on-off control whereas WS2812s support 3 colors and dimming so they need 24-bits per LED (3 bytes per LED).
I've got a project with 48 addressable LEDs using six daisy-chained MAX6968 chips, which are shift-register addressed (3 connections to the Arduino) and they have built-in current limiting so the LEDs don't need a series resistor.
That's the question.
In addition, do you want RGB or single colour LEDs?
WS2812/ "NeoPixel"s are RGB with a substantial range of colours. Each "pixel" draws between 1 mA when dark and 55 mA full white. They are wired in a chain connected from one to the next. They are available as strips or ready-wired chains.
If you only want single colour LEDs, on or off, a MAX7219 can drive 64 LEDs in a matrix with 16 wires and several can be wired together to be controlled by just three I/O pins. Five of them could drive 320 LEDs, available in the form of these modules:
Modules are cheap - ignore the matrix provided; wire your own matrices.
If the LEDs are supposed to travel with their bags placed in no particular place -
Lots of ESP01's and a ESP-Now network; easy, but no phone app.
Lots of ESP01's and as many Blynk_IoT accounts; more complicated, but 'app-ready'.
That would be a serious problem!
Good application for ESP01s which can run from two alkaline "AA" cells. 300 would probably cost not much more than $1000. 
Are these bags stored in fixed locations, e.g. on shelves or in "pigeon holes"? Or in a jumbled pile?
If they are stored in large pigeon holes, for example in a 50x6 grid, you could maybe reduce down the number of LEDs by only having LEDs for the columns and rows. You would light the leds for the column and row in the grid where the customer's bag is located.
If they are in a jumbled pile, LEDs are not going to work: they may not be visible. You could look at RF tags. You can get handheld readers which will help you find a particular tab by beeping faster as you get closer to the tag. Readers like these are not cheap!
If you must have 300 LEDs and need to keep costs down, then another idea would be to use charlieplexing. With 18 Arduino pins, you can light one of up to 306 single-colour LEDs.
They will all be hanging on individual hangers next to each other attached to bags. I need to get a bag/light to associate with an individual customer with several items being put into the bag throughout the day. Once the customer arrives I want to light up their bag for quick access. Currently we dig through bags in alphabetical order trying to find a customers bag which isn’t always in the correct place. I appreciate all the suggestions.
Imagine a restaurant pager letting you know your table is ready type of concept with one led showing me which bag my customers stuff is in.
Oh, so my guess was correct?
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