Help!!! for an iOS compatible smart watch!

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Hi friends, this is my first post here,i am Devang, i am trying to make a smart watch... that is

Open source(based on arduino)
Under 25$
Has an app on IOS(Will take care of that later this year !)
Anyone can make their own OS!

Story- So i have kept its name BIOMI , i wanted to design a perfect watch that has a low cost and could be
customised to everyone's need by themselves .

Work till now (hardware) - Till this moment, i have designed a 3D printed case for it ! It contains an arduino pro mini , a HM-10 bLE 4.0 bluetooth module, an rotary encoder and a large 1.8'' TFT colour LCD ! And also a 1000 mah lipo and a charger. So the hardware part has been finished!

Work till now(Software) - So here's the major setback! I am an 8th grader and till now the best Arduino project i have successfully made is a 4 digit passcode arduino locking system ! .
Because Atmega 328 only has 32 KB, i want to make a program( for now i call it THE CORE ) that automatically takes all the code from a folder in a SD card from my TFT module and lets me get upto potentially 128 GBs of programming space(just kidding- no need for 128 GB) . But the problem is i have no idea how to make it . Please help!
2) the actual program(OS) - So till now i have been able to use the bluetooth module to , i have been able to use the encoder and read its readings via serial and use the TFT to display bitmaps . So i have NO IDEA how to receive notifications from my iPhone to my arduino! Please help!

*Final questions
1)How do i make a code that will automatically get the other (OS) code from a SD card ?
2)How to receive notifications from my iPhone ? (via ANCS) I read a guys code, but its for a LCD and the library written by him cannot be changed to my needs .

I believe that phones also use a code similar to what i plan to make because IOS is always downloaded and takes on 2-3 GB on the phone's storage rather than the phone's processing chip!

But the problem is i have no idea how to make it . Please help!

Can't be done with an Arduino - unless you use an interpreter like bitlash but than one on steroids. Never seen such code here in the last 5 years so I think quite impossible.

but feel free to prove me wrong..

Ohh . Thanks for replying! So is there any other way i can extend the storage on the Atmega 328 ?

Check out the Teensy 3.1. 256K flash, 64K RAM, and I'm not sure how much EEPROM. Right now it's a bit pricey, but by the time you finish a project like this, it might be a good bit less expensive. Oh, and it's Arduino IDE compatible.

Ohh . Thanks for replying! I will check out the Teensy 3.1 and see if its available in India otherwise it might take upto 1 month to reach me from any other country.
In the mean time does anyone know how to get notifications from my iphone to my arduino via bluetooth ? ( ANCS )

robtillaart:
Can't be done with an Arduino - unless you use an interpreter like bitlash but than one on steroids. Never seen such code here in the last 5 years so I think quite impossible.

but feel free to prove me wrong..

Sir, i found that if i use bit lash , it will take 16Kb on the atmega chip, but in return it will help me because its codes are easier than the normal arduino codes and the BIGGEST advantage is that i can access the code from a SD card ! So the first question is solved ! All thanks to you !
I will test it later today.

Only problem now left is how to get notifications from my phone via bluetooth?

anybody ?

I'd give up your idea for iPhone connectivity. iOS wasn't built to interface with arduino natively. You would have to build an iOS app to communicate with your watch via Bluetooth since that's the only wireless module you have.