Custom Retail Security System Development

I'm seeking an experienced hardware and software developer to create a bespoke security system for our retail store. The system should be composed of a hook-type device that, when unhooked from the product, emits a signal detectable by a wall-mounted receiver.

Hardware:
- Design a hook-type security device attachable to product.
- The device should emit a signal when unhooked, using custom RF technology.
- It needs to be small, battery-powered for easy attachment to clothing.

Signal Transmission & Detection:
- The device should only send a signal when unhooked.
- A wall-mounted receiver will detect the signal and trigger a notification to our system.
- The detection range should be adjustable, covering at least a few meters.

Ideal Freelancer Skills:
- Proficiency in custom RF circuit design.
- Extensive knowledge of embedded systems and IoT.
- Prior experience in designing retail security systems is a plus.