Developing an IoT dash button prototype

Inspired by the Amazon Dash button, we want to develop a call system with dash buttons. The function of the dash button should be: - One click = data base entry on SQL server/cloud - Long click = delete last data base entry on SQL server/cloud - Battery low = data base entry on SQL server/cloud - receive feedback and indicate to button pressing person via LED (green/red LED) - WiFi based - connection for installation either via hotspot or acoustic (like Amazon Dash button) - Energy-saving (switch off when not in use, activate per click via DHCP) and using a battery - as small as possible (can be discussed for further development phase) - as cheap as possible (material costs <30 US$) Administration of multiple buttons in a database on the server must be possible. It must be possible to refer a "click" of a specific button to this unique button, e.g. via MAC. Housing design will be up to a different project. Only a working system that can be replicated qualifies for project acceptance. Further details on request.