Programmer to write a Python REST Web Service API and also Python GUI application for Raspberry Pi – Immediate Start

My company is building some hardware with an embedded Raspberry Pi (latest; model 2) at its core. The Pi essentially turns GPIO pins on or off (GPIO outputs) which is wired into a custom made circuit board (Pi Hat) which in turn controls our hardware. The Pi also listens for changes in certain GPIO input pins and performs actions once a change is detected – i.e. events attached to these input pins. We have the need for a programmer to write some software for the Pi: (i) A web service API using REST principles that runs on the Pi and serves as the interface to the GPIO output and input pins. (ii) A GUI application also in Python that the user will interact with via an LCD touch screen. As the user taps the buttons on the LCD screen the application will make HTTP GET/POST API calls to perform the various hardware functions. (iii) Complete and detailed instructions on how to install onto a new Pi that our assembly team can follow. Step-by-step as these will not necessarily be Linux experts. The API specification will cover about 12 different methods, each doing a particular task. The tasks are relatively simple, like sending a digital 1 or 0 to a GPIO pin, reading a pin’s value or taking a photograph (some of the Pi’s will have the camera installed). In time, desktop and mobile web applications will be built that will also interface with this API, which is why the API interfaces the hardware as opposed to the GUI doing GPIO directly. The Pi should be able to be rebooted (deliberately or otherwise!) and be operational when it comes back up – both the API and the GUI app – so this implies you will need to include with your instructions what commands need to be run or boot files configured at the operating system level. Be sensitive to any permissions required remembering this should boot and be fully operational without any human intervention. Think of it’s a being embedded inside the hardware (which it is) and deployed to distant locations. The GUI application should also auto-boot and not rely on the Linux X environment in any way. We want this solution to be fast, reliable and not allow the user to exit the application. Think self-service kiosk. This GUI application is the only interaction the user will have with the Pi. Administrators and support personnel will use SSH over Ethernet for system management and maintenance. We would like to be able to update both the API and the GUI application remotely. There may be a web service method for this, cron job to pull down the latest version, etc. We are open to suggestions on how best to achieve this. We are also open to suggestions on any methods, frameworks or toolkits we should adopt to achieve the following objectives: • GUI application can scale to either a 4” or 7” LCD touchscreen • Fast with no lag • Ultra reliable and stable – no out of memory exceptions, etc. • Remotely updateable • Uses industry best practices – REST for example and proven libraries • Not interested in Java, Mono, Lazarus, etc unless you can provide a compelling reason why we should. • First working alpha within a week We are not looking for the cheapest rate, rather a professional with excellent written English who can achieve all of our objectives above. Time zone, location is not important but do note we are on a tight timeline hence the first working alpha within 7 days. Please list your hourly rate, whether you have availability to meet our timeline and details of previous experience with similar projects. As a professional courtesy - please, no time wasters. If you cannot 100% put your hand on your heart and deliver our objectives then please do not apply. I trust you understand. You will have unlimited access to our technical product manager via IM (Hangouts, Skype, etc).