Arduino + Bluetooth + App

We are looking to quickly prototype a combined hardware + app device.

Hardware Functionality:
The main element should be small a footprint device (like an Arduino nano).

Something like this may be suitable: https://www.robotshop.com/uk/bluno-nano-arduino-ble-bluetooth-microcontroller.html?gclid=CjwKCAjwuO3cBRAyEiwAzOxKsi6JeE-lbourj9Sxrs6h0CHLdVyzX2HUajsFoIc-pMNLN5d929sOGRoCBVoQAvD_BwE

An optosensor such as QRD 1114 should be attached to the Arduino pinout. When the optosensor signal goes high, the Bluetooth HID should send out a character chain (such as "A" for example) to be read by the app.

App:
For testing purposes, we need to incorporate a video player in an app. The app should have a listener thread running in the background to catch the Bluetooth output.

When a Bluetooth pulse is detected the media (film) plays for 5 seconds. If no Bluetooth signal is detected for 10 seconds the media pauses.

We hope this should be a fairly straightforward job for anybody with Arduino/Bluetooth experience and knows how to build a small app.

We are happy to consider proposals higher or lower than the price indicated.