We are always running out of essential food and drink in our house, despite having plenty of opportunities buy replacements, because we are over-tired parents. The obvious solutions here are: 1. Wait for an affordable and functional 'smart-fridge' (maybe a long wait), or 2. Use a list app on a smartphone to record what we need and refer to it when out shopping. The problem with this second solution is that it never actually works - my phone is never nearby when I open the fridge door to see there is no milk left - and by the time I have found my phone I will have forgotten about the milk.
So what I want is something permanently there on the fridge and I can just press a button to say we need milk, or cheese, or beer or whatever. This will then update a shopping list that can viewed on a smartphone online or via an app. All of this could of course be done with a touch screen tablet stuck to the fridge door, but this would be relatively expensive and wasteful (both in terms of technology and power) for what is a very specific task. To keep the costs low (and also to have fun and learn lots of new things) I want to build it (both the hardware and software) from scratch.
My initial plan is to use an Arduino (compatible) board and touch screen TFT shield: this is mainly because this makes it easy to construct and mount, and they can be bought very cheaply (A Mega clone and 4" touch shield for about £10 ($15) from China). WiFi connectivity will use the super-cheap ESP8266 module. Connectivity to optional peripherals - a barcode scanner and load cells - will use ultra-cheap and low power nRF24l01 modules. Power will come from a thin Li-ion cell.